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PICList Thread
'guitar tuner, PIC & MIDI (was:Freq.counter)'
1995\07\07@152636 by Uwe Schueler

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>... David's guitar tuner project .....

how about amplifying,low-pass filtering ( 3rd order), and clipping
the guitar signal with a cheapo 324 quad-opa. Generate the desired
reference freq. with the RTCC. Make a software-PLL style frequency-
comparator ( edge-triggered RS-flip-flop )which is set by ref.-timing
and reset by input signal . Connect a 'sharp' LED to the Fin>Fref port and
a 'flat' LED to the Fref>Fin port. As the input freq. comes up/
down towards the ref.freq. the flat/sharp LED will dim.
Just a quick idea; don't know if it makes sense.
Another idea, not mine , saw it on Frankfurt Musik fair about 10yrs ago:
A guy fed a bright LED with a microcontroller generated reference
frequency  and used the stroboscobe effect to visually tune the strings
without making noise - nice !

>It would be interesting to also pursue the generation of MIDI from a
>guitar signal ....

and from other real world events.  In my free-time ( not much) I currently
work on such a project : a microphone is placed at each end of a 1m plastic
tube. If you hit the tube with e.g. a drum-stick the mikes generate pulses
with a runtime delay. A 16C54 along with a 324 opamp digitizes these pulses
( MIDI key velocity ) and calculates a MIDI-note-# from the trigger delays.

I 'll put schematics, layouts + code related to MIDI, musicelectronics, PICs
and other controllers on my ftp site as soon as possible ( late summer ?)
Will be announced here and on MIDI.boards

P.S.
I too have some code that sends MIDI. MIDI IN is tough.
a 20MHz PIC with HW-interrupt could do it. Somebody tried it ?
Anybody else doing MIDI with PICs ?
Uwe Sch"uler    __\     /__ ein genie
Physiologie      --\,,,/--  das sich nicht geniert
Gmelinstr.5        /" "\    ist wie ein rentier
D-72076 T"ubingen  \_V_/    das sich nicht rentiert
Tel: (49) 70 71 29 - 30 72  Fax: - 30 73

1995\07\07@153926 by Lou Sortman

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> Another idea, not mine , saw it on Frankfurt Musik fair about 10yrs ago:
> A guy fed a bright LED with a microcontroller generated reference
> frequency  and used the stroboscobe effect to visually tune the strings
> without making noise - nice !

Oh man, I've gotta try it!

1995\07\07@162149 by Mike Brothers

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On Fri, 7 Jul 1995, Lou Sortman wrote:

> > Another idea, not mine , saw it on Frankfurt Musik fair about 10yrs ago:
> > A guy fed a bright LED with a microcontroller generated reference
> > frequency  and used the stroboscobe effect to visually tune the strings
> > without making noise - nice !
>
> Oh man, I've gotta try it!
>
Must have to darken the room to tune??  Anyone have any ideas, helpful
hints to get this to work?  Seems that it would be a rather stright
forward project!

spam_OUTelectronTakeThisOuTspamwln.com

1995\07\07@190930 by David B. Thomas

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Your suggestion for dealing with the harmonics is great.  But my tuner
attempts to determine by itself which string is being tuned.  I suppose
with expensive programmable filters you could detect the pitch, then dial
in the filter real quick to protect against the harmonics, which
intensify with time.  But if you put in a filter sufficient to chop the
harmonics of the low E string (86 Hz or so) you'd never pick up the high
E two octaves up.

My hackbuddy and I have decided to return to this project and see if we
can get it to work.  The idea will be: count on the fundamental being
strong for the first several cycles (seems to be safe), then start
ignoring any transitions that aren't close to the expected timings.  For
example, if you're tuning the 110 Hz A string, you'd initially get a 110
cycle square wave.  Then as the vibrations decay, you'd start seening
double, triple, or some oddball combination.  If I remember right, the
second harmonic is the most prominent and can be isolated.  But I'll have
to look again.  Anyway, it might be as simple as ignoring every odd
pulse, once the expected pitch is established.  Owell I'll try it and
post the results!

ps: about the code I've offered to put up... I was going to make it
available via ftp this morning but I forgot to move the files.  I'll do
it tomorrow when I'm dialed in from home.

David
--
Their address sums up their attitude: One Microsoft Way
       http://www.rt66.com/dthomas/

1995\07\07@192632 by David B. Thomas

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Lou> > A guy fed a bright LED with a microcontroller generated reference
Lou> > frequency  and used the stroboscobe effect to visually tune the
Lou> > strings without making noise - nice !

Lou> Oh man, I've gotta try it!

Mike> Must have to darken the room to tune??  Anyone have any ideas,
Mike> helpful hints to get this to work?

Real men use xenon flash tubes.

David
--
Their address sums up their attitude: One Microsoft Way
       http://www.rt66.com/dthomas/

1995\07\08@111432 by CRSO.pic

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David, here are a few suggestions for a solution to your problem with
harmonics:

1)  Use a dual speed PLL to initially lock onto the strong fundamental
   in 'fast' tracking mode and then automatically switch to 'slow' mode
   to stay locked onto the decaying fundamental (decrease capture
   range). The 'fast' speed would be optimized to lock onto the
   fundamental quickly and the 'slow' speed would be fast enough to
   track tuning variations but too slow to 'jump' over to a harmonic.
   The fundamental could then be measured by coupling the vco to the
   pic.

2)  Use zero crossing detection. It has the unique property of allways
   digitizing the lowest frequency, even if its not the strongest.
   A well designed front end, and possibly threshold tracking to
   maintain sensitivity could be used to extend its range.

3)  Use a switched capacitor filter with external clock input configured
   as a 'comb' filter. Lock on to the fundamental and feed it into the
   filter's clock, thereby attenuating its harmonics. Something
   creative would need to be done here to aquire the fundamental in the
   first place.

4)  Use the pic to implement an FIR or IIR filter.

5)  Use the pic to integrate its measurement of frequency and then use
   that to detect the rate-of-change. If the rate of change (slope)
   exceeds a pre-set value then we know the detection circuitry has
   switched from the fundamental to a harmonic. At that point in time
   divide the new frequency measurement by the fundamental to calculate
   the harmonic factor and use that factor in subsequent calculations.
   This idea would work best if the signal were processed first by a
   PLL to lock onto a single spectral component. In fact, you could use
   the lock detection circuitry of the PLL to detect when the
   switchover to a harminic occurs.

6)  Can you tell if a note is sharp or flat from its harmonic as well as
   from its fundamental? If so, then use a PLL front end to purify the
   spectrum (one frequency at a time) and do your function on the VCO
   signal.

7)  Use an analog input and implement a PLL in pic firmware, using a
   combination of the above ideas.

I really know absolutely nothing about music, but I hope these ideas are
usefull, or stimulate the formulation of new ones.

Regards, Dana Frank Raymond - Foxtrot Systems Ltd.
Internet: .....dana.raymondKILLspamspam@spam@canrem.com. Compuserve: 73362,3052

1995\07\08@221133 by David B. Thomas

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On Sat, 8 Jul 1995, Dana Raymond wrote:

> 1)  Use a dual speed PLL to initially lock onto the strong fundamental

Would it really stay locked to the weak fundamental?

> 2)  Use zero crossing detection. It has the unique property of allways
>     digitizing the lowest frequency, even if its not the strongest.

It can't be that easy, can it?  I'm already amplifying and heavily clipping
the signal.  Isn't that the same thing?  Maybe I need to read up on zero
crossing detection.

> 3)  Use a switched capacitor filter [...]

Impractical but clever.

> 4)  Use the pic to implement an FIR or IIR filter.

What are these?

> 5)  Use the pic to integrate its measurement of frequency and then use
>     that to detect the rate-of-change.

What I was planning was simpler.  Once the harmonic kicks in I'll be able
to recognize it because transitions will suddenly arrive way too early.
I can simply discard transitions that aren't within a few percent of
where I expect to find them.

> 6)  Can you tell if a note is sharp or flat from its harmonic as well as
>     from its fundamental? If so, then use a PLL front end to purify the
>     spectrum (one frequency at a time) and do your function on the VCO
>     signal.

How does one "purify a spectrum" with a PLL?  What does that mean?  But
yes of course it is possible to track changes in a harmonic as readily as
the fundamental.

> 7)  Use an analog input and implement a PLL in pic firmware, using a
>     combination of the above ideas.

I've done this for another project and it worked *very* well.  However I
was able to isolate the fundamentals with analog filters ahead of time.

Thanks for all your cool suggestions.

David
--
Their address sums up their attitude: One Microsoft Way
       http://www.rt66.com/dthomas/

1995\07\10@111741 by Tim Braun

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> From @uga.cc.uga.edu:owner-piclistspamKILLspamMITVMA.MIT.EDU Fri Jul  7 14:28:45 1995
> From: Uwe Schueler <.....uwe.schuelerKILLspamspam.....UNI-TUEBINGEN.DE>
> Subject:      Re: guitar tuner, PIC & MIDI (was:Freq.counter)
>
> >... David's guitar tuner project .....
>
> how about amplifying,low-pass filtering ( 3rd order), and clipping
> the guitar signal with a cheapo 324 quad-opa. Generate the desired
> reference freq. with the RTCC. Make a software-PLL style frequency-
> comparator ( edge-triggered RS-flip-flop )which is set by ref.-timing
> and reset by input signal . Connect a 'sharp' LED to the Fin>Fref port and
> a 'flat' LED to the Fref>Fin port. As the input freq. comes up/
> down towards the ref.freq. the flat/sharp LED will dim.
> Just a quick idea; don't know if it makes sense.

This has some possibilities.  But you need to guess the reference freq.
from early edge crossings to get the correct string.  Help me out now,
what would the algorithm look like in pseudo-code?

wait for an edge crossing.
start a timer.
next edge crossing is 1/2 period.
estimate string, get reference period, set up reference period in RTCC.
loop
 wait for an edge or RTCC timeout.
 if edge
  set sharp LED. ;; you'd want to re-sync the RTCC?
 if RTCC
  set flat LED.  ;; you'd have to re-sync the RTCC to the next edge?
 if (too many RTCC's with no edge)
  break, restart

So when you're close to 'in-tune', both LED's would be on?

> >It would be interesting to also pursue the generation of MIDI from a
> >guitar signal ....
>
> and from other real world events.  In my free-time ( not much) I currently
> work on such a project : a microphone is placed at each end of a 1m plastic
> tube. If you hit the tube with e.g. a drum-stick the mikes generate pulses
> with a runtime delay. A 16C54 along with a 324 opamp digitizes these pulses
> ( MIDI key velocity ) and calculates a MIDI-note-# from the trigger delays.

This sounds like a really fun midi-trigger.  I'd like to get a hold of
some of your results.  Are you digitizing Mike output with RC discharge
time?

> I 'll put schematics, layouts + code related to MIDI, musicelectronics, PICs
> and other controllers on my ftp site as soon as possible ( late summer ?)
> Will be announced here and on MIDI.boards

I'll look forward to this.

> P.S.
> I too have some code that sends MIDI. MIDI IN is tough.
> a 20MHz PIC with HW-interrupt could do it. Somebody tried it ?

32 usecs/bit doesn't leave much time.  Setting up an 'hc11 is quite
a bit easier.

> Anybody else doing MIDI with PICs ?

Not yet, but when my (non-existent) free time allows ..

> Uwe Sch"uler    __\     /__ ein genie

Tim Braun                             |
Continental Healthcare Systems Canada | Voice: 204-942-2992 ext 228
1900-155 Carlton St                   | FAX:   204-942-3001
Winnipeg, Manitoba, Canada R3C 3H8    | Email: EraseMEtimspam_OUTspamTakeThisOuTchs.mb.ca

1995\07\10@114056 by David B. Thomas

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On Mon, 10 Jul 1995, Tim Braun wrote:

> This has some possibilities.  But you need to guess the reference freq.
> from early edge crossings to get the correct string.  Help me out now,
> what would the algorithm look like in pseudo-code?
>
> wait for an edge crossing.
> start a timer.
> next edge crossing is 1/2 period.

Are you sure you can assume 50% duty cycle?  Depending on the DC level
when you clip, the 1/2 cycle transitions will hopefully be near the
middle but you can't count on the exact timing.  I time from one
low-to-high transition to the next to unask this question.

The rest of your algorithm looks good.  What I do is wait for the edge,
then peek at the RTCC and look up the count in a table.  See
http://www.rt66.com/dthomas/pic/pic.html if you want to see my tuner so
far.

David
--
Their address sums up their attitude: One Microsoft Way
       http://www.rt66.com/dthomas/

1995\07\10@132711 by Sun St Louis

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I may have mailed this incorrectly.  If not, sorry for the duplicates. . .

{Quote hidden}

Please help my confusion - it seems to me that we are trying to over engineer
what could be an easy solution.

Wouldn't the normal tuning process be:
1.  "Pluck" the string.
2.  Listen for it being sharp or flat.
3.  Tune the string.
4.  Re-pluck the string.

If this is the case, why worry about decaying harmonics?  Just count
the number of zero crossings in 100 msec & compair to a table of expected
values.  If it is high or low out-of-range discard it & try again.

Even if you tune on the fly ( i.e. pluck-listen-tune as a single process); I
would think you could still get a good frequency sample after 2 sec.  I could
be wrong here - I've never tried it.

I don't know much about guitars.  But I think the difference between the
1st string (low E) and the 6th (high E) is 2 octaves.  With a string way out-
of-tune, I think it is possible to tune to the frequency of another string.
Taking a string this far out-of-tune would be undetectable by your circuit.
You may want to consider using 8 LEDs: 1 per string, plus a high and low
indication.  This would let you know which string the circuit thought you
were tuning.


Jon Poland
Sun Microsystems Inc.
St. Louis, MO
(314) 569-4716
@spam@jon.polandKILLspamspamcentral.sun.com

1995\07\10@175326 by David B. Thomas

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On Mon, 10 Jul 1995, Jon Poland SE Sun St Louis wrote:

> Please help my confusion - it seems to me that we are trying to over engineer
> what could be an easy solution.
>
> Wouldn't the normal tuning process be:
> 1.  "Pluck" the string.
> 2.  Listen for it being sharp or flat.
> 3.  Tune the string.
> 4.  Re-pluck the string.

No.  The way guitar players generally tune is to hit the string once,
good and hard, then adjust the peg as the string is decaying.  That
way you can adjust a continuous pitch until it's right.  If you try to
tune with only "that was too high" type information, it takes way too
many tries.  Being off by even a few cents is enough to make the
instrument sound sour.

> Even if you tune on the fly ( i.e. pluck-listen-tune as a single process); I
> would think you could still get a good frequency sample after 2 sec.  I could
> be wrong here - I've never tried it.

2 sec. is enough time to know if you're right or not, but it's not
enough time to bring the string in.

> I don't know much about guitars.  But I think the difference between the
> 1st string (low E) and the 6th (high E) is 2 octaves.

<nod>

> With a string way out-
> of-tune, I think it is possible to tune to the frequency of another string.

Guitarists are smarter than this.  Very few guitar players have any
trouble at all getting it close, even very close, by ear.  The tuner
is just used for fine tuning.  Also, guitars tend to drift some but
not a lot.  A guitar that was packed up a month ago is unlikely to be
so far out of tune that an autodetect mechanism would identify the
wrong string.  And most musicians wouldn't fall for it even then.

Still, your idea of providing a display that shows which string was
detected is a good one, provided you can afford to add it in your
particular application.

David
--
Their address sums up their attitude: One Microsoft Way
       http://www.rt66.com/dthomas/

1995\07\11@130232 by CRSO.pic

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-> > 1)  Use a dual speed PLL to initially lock onto the strong
-> Would it really stay locked to the weak fundamental?

Yes, I believe so. A PLL CAN track a signal outside its capture range if
it has been locked onto it in the first place and its loop
characteristic are such that it resists change that is too fast (a
change from the fundamental to a harmonic can be considered a fast
change). When the harmonic comes into the capture range (close enough in
frequency and strong enough compared to the fundamental) the PLL won't
move to it because its loop characteristics inhibit fast change.

-> It can't be that easy, can it?  I'm already amplifying and heavily

No, you're right, I goofed. I'm still trying to find the reference in
"The Art of Electronics" that got me confused on that one (An excellent
reference BTW. I highly recommend it).

-> > 4)  Use the pic to implement an FIR or IIR filter.
->
-> What are these?

Digital filters. You need a very fast CPU with an analog front end.

-> How does one "purify a spectrum" with a PLL?  What does that mean?
-> But yes of course it is possible to track changes in a harmonic as
-> readily as the fundamental.

What I mean by that is that A PLL will lock onto one spectral component
(frequency) if it is coherent, stays within the tracking range, and
doesn't change too fast (slew rate). If you take a standard audio range
PLL and pluck a guitar string the PLL's oscillator will be one
frequency; The base note (terminology correct?), and the phase should be
shifted at around 90 degrees from the fundamental. The PLL will either
stay locked onto the fundamental or switch abruptly to a harmonic if
that harmonic is strong enough.

By measureing the PLL's oscillator frequency, you arn't getting a lot of
noise due to harmonics. Its only one frequency, changing over time.

Good luck with your project.

Regards, Dana Frank Raymond - Foxtrot Systems Ltd.
Internet: KILLspamdana.raymondKILLspamspamcanrem.com. Compuserve: 73362,3052

1995\07\11@143601 by David B. Thomas

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On Tue, 11 Jul 1995, Dana Raymond wrote:

> Yes, I believe so. A PLL CAN track a signal outside its capture range if
> it has been locked onto it in the first place and its loop
> characteristic are such that it resists change that is too fast (a
> change from the fundamental to a harmonic can be considered a fast
> change).

Okay yeah this makes sense.  I just need to make the loop fast enough to
lock onto the fundamental before the harmonic gets too strong (500 ms
response is plenty good enough) but slow enough that the almost-instant
switch to the harmonic doesn't -- scuse the pun -- phase it.

I'd really like to try this approach.  What would be some audio PLLs to
use?  Perhaps a 565?  567?  Or are there more modern, better ones?  I've
worked extensively with RF type PLLs (gotta whole drawer full of motorola
chips) but never worked with audio PLLs.

Incidentally, for anybody wanting to use a PIC to tune an RF circuit, I
highly recommend the MC145170 chip.  It's cheap (about $8), readily
available (Hamilton Hallmark, Newark), and miraculous.  Programmed with 3
wire interface.  Reference modulus can be any number from 4(?) to 32767.
Programmable divider from 40 to 65535.  Can be programmed to be
single-ended or dual-ended.  Ref. output available.  Sign of loop can be
inverted by programming.  Can directly synthesize up to 160 mc.  XTAL ref.
osc. on-board.  16 pin package.  I've used these with PICs and they work
great.

David
--
Their address sums up their attitude: One Microsoft Way
       http://www.rt66.com/dthomas/

1995\07\12@104408 by Doug Sellner

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All one needs is an audible tone refference to tune the guitar.  As the two
tones get closer they cause a 'RING' which allows a semi skilled musician
to tune-a-fish.

Doug Sellner
Beach Tech
4131 Vincent Avenue South
Minneapolis MN 55410

Voice (612) 924-9193 x 521
Fax   (612) 926-1145

Internet: RemoveMEdsellnerTakeThisOuTspamembay.com

1995\07\12@113047 by Tim Braun

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> Date:         Tue, 11 Jul 1995 21:46:25 -0500
> From: Doug Sellner <spamBeGonenewsspamBeGonespamEMBAY.COM>
> Subject:      Re: guitar tuner, PIC & MIDI (was:Freq.counter)

> All one needs is an audible tone refference to tune the guitar.  As the two
> tones get closer they cause a 'RING' which allows a semi skilled musician
> to tune-a-fish.

Using 'beating' to tune a guitar is fine and good when you can hear the
guitar and reference ...

There are many commercial tuning devices on the market, any which
I've looked inside are based on microcontroller technology.  This is
a great application for a PIC.

> Doug Sellner

> Internet: TakeThisOuTdsellnerEraseMEspamspam_OUTembay.com

Tim Braun                             |
Continental Healthcare Systems Canada | Voice: 204-942-2992 ext 228
1900-155 Carlton St                   | FAX:   204-942-3001
Winnipeg, Manitoba, Canada R3C 3H8    | Email: RemoveMEtimspamTakeThisOuTchs.mb.ca

1995\07\12@114547 by David B. Thomas

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On Tue, 11 Jul 1995, Doug Sellner wrote:

> All one needs is an audible tone refference to tune the guitar.  As the two
> tones get closer they cause a 'RING' which allows a semi skilled musician
> to tune-a-fish.

Yeah that "ring" is called beating.  It's the difference between the two
frequencies.  And you are right that lots of musicians use this technique
all the time and it works great.

However, a lot of musicians prefer to use electronic tuners, at least in
some situations.  Particularly, stage musicians like to have them.
You're playing and a string breaks -- you finish the song, then hit a
foot pedal and suddenly your tuner (with visual indicator) is in circuit
and your amp is not.  You tune up without bothering the audience, then
you're back in business.  Or, let's say another band is playing, and your
band is up next.  You probably couldn't hear yourself to tune, perhaps even
with a headset.

I personally am very accustomed to relying on my ears, a lot more than
electronic measuring devices.  I've never tried to play an instrument on
stage that I didn't first check with my ears.  But a lot of pro musicians
do this sort of thing all the time.

David
--
Their address sums up their attitude: One Microsoft Way
       http://www.rt66.com/dthomas/

1995\07\14@043548 by Chris Madden

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       Check out the "comp.dsp" newsgroup for a similar discussion.

       Chris Madden
       maddencEraseMEspam.....itd1.ul.ie

1995\07\15@143142 by Tim Braun

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Well, I've had this response on my desk-top for a few days,
better get it away, though some of the comments I make here
have been made already.

{Quote hidden}

Being a guitarist, and having used a tuner, and having attempted to design
a tuner, once, I'll share a bit of my experience.  I don't think we're over-
engineering yet.

> Wouldn't the normal tuning process be:
> 1.  "Pluck" the string.
> 2.  Listen for it being sharp or flat.
> 3.  Tune the string.
> 4.  Re-pluck the string.

Guitarists pluck the string and adjust the tuning while it sounds, and I for
one would not consider it useful to have to stop the string and re-pluck
to check the adjusted frequency.

> If this is the case, why worry about decaying harmonics?  Just count
> the number of zero crossings in 100 msec & compair to a table of expected
> values.  If it is high or low out-of-range discard it & try again.

The upper harmonics do decay quite quickly.  The first and second harmonic
can be a problem.

> Even if you tune on the fly ( i.e. pluck-listen-tune as a single process); I
> would think you could still get a good frequency sample after 2 sec.  I could
> be wrong here - I've never tried it.

I normally don't get a useful tuning measurement out of my commercial tuner
until about 1/2 second after the string is plucked.  If you can't get a
good frequency sample for 2-5 seconds/pluck, it is really laborious to
tune.

{Quote hidden}

The two E strings are indeed 2 octaves apart.  You can indeed tune a string
down to the next one, if you try.  The harmonics on a given pluck on a string
won't let you simply count zero crossings, as you can pluck to generate
harmonics or not.  The zero crossings should be harmonically related, though.

The low E is about 82.41 Hz, the A is about 110.0 Hz, the high B is
247.2 Hz, high E is 329.6 Hz.   Referenced to A-440Hz.  It's very useful
to be able to adjust the reference of a tuner.  Acoustic pianos are out
most of the time in most places.

Tim Braun                             |
Continental Healthcare Systems Canada | Voice: 204-942-2992 ext 228
1900-155 Carlton St                   | FAX:   204-942-3001
Winnipeg, Manitoba, Canada R3C 3H8    | Email: RemoveMEtimTakeThisOuTspamspamchs.mb.ca

'PIC & DSP'
1995\07\19@170636 by Rodger Richey

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    Microchip will be offering two new devices in the PIC17CXX family with
    the 8x8 hardware multiply that executes in a single instruction cycle.
    Some of the features of these devices are:

              PIC17C44
    ----------------------------------
     58 single word instructions
     DC - 25MHz clock input
     8K words of program memory
     454 bytes of data memory
     supports external memory (64Kx16)
     8x8 hardware multiplier
     33 I/O pins
     2 capture inputs
     2 PWM outputs
     4 timer modules
     USART
     Watchdog Timer

    The PIC17C43 offers the same features of the PIC17C44 except that is has 4K
    of program memory space.

    Rodger Richey
    Microchip Technology Inc.


______________________________ Reply Separator _________________________________
Subject: PIC & DSP
Author:  Dana Raymond <EraseMEdana.raymondspamspamspamBeGonecanrem.com> at Internet_Exchange
Date:    7/19/95 3:15 PM


Just a little note along the lines of FFT and DSP:

Microchip's application note AN542 implements FFT functions on a 17C42
PIC.

Also, I've heard from Microchip that they plan on offering a PIC with an
8X8 single instruction cycle hardware multiply. I wasn't given any more
detail, but such a chip would be suitable in low end DSP applications.

Regards, Dana Frank Raymond - Foxtrot Systems Ltd.
Internet: RemoveMEdana.raymondKILLspamspamcanrem.com. Compuserve: 73362,3052


'I2C, PIC & PC Parallel Port'
1996\12\18@120223 by arry P. Thomas WA0GWA
flavicon
face
I'm working on some PIC devices and intend to use some I2C code to code up
the slave routines.  I found routines to let me use PC parallel port as
master to test my slave devices but the references I found all use some sort
of hardware on the PC port such as a 74LS05 to aid in the bidirectional I2C
implimentation. Since some of the parallax products seem to use I2C to talk
between the PC and the target system without any extra hardware at the PC
end, I was wondering if anybody had any info on how to do this.  The
hardware is simple enough, I just was trying to avoid a trip to the city to
get the parts for the I2C PC port interface.

Thanks
Larry
-----------------------------------------------------------------------
Larry P. Thomas wa0gwa              voice : 1 913 888-0282
Krell Technologies                    fax : 1 913 782-9359
8960 Bond                           pager : 1 816 989-HELP
Overland Park, KS 66214-1764       e-mail : lpthomasSTOPspamspamspam_OUTwinning-edge.com
                                      www : http://www.krell.com
-----------------------------------------------------------------------

1996\12\18@231526 by Steve Hardy

flavicon
face
> From: "Larry P. Thomas WA0GWA" <spamBeGonelpthomasSTOPspamspamEraseMEWINNING-EDGE.COM>
> I'm working on some PIC devices and intend to use some I2C code to code up
> the slave routines.  I found routines to let me use PC parallel port as
> master to test my slave devices but the references I found all use some sort
> of hardware on the PC port such as a 74LS05 to aid in the bidirectional I2C
> implimentation. Since some of the parallax products seem to use I2C to talk
> between the PC and the target system without any extra hardware at the PC
> end, I was wondering if anybody had any info on how to do this.  The
> hardware is simple enough, I just was trying to avoid a trip to the city to
> get the parts for the I2C PC port interface.

Since I2C requires open collector drivers, you may be able to get away
with using a diode (cathode to the output) to simulate one.  This is a
bit bodgy since the diode drop (0.6V) may put you over the guaranteed
logic low level.  Try dusting off your old OA91 germanium diodes (0.4V)
or dismantle an old SMPS for its Schottky diodes (0.4V or less).  The
100 Amp stud-mount types are best - throw away the heatsinks though
'cause you won't be a-needin'em.

Otherwise, use a couple of small NPN's (2n2222) in common emitter/open
collector mode - use resistor in base drive and invert the output
levels from 'standard' I2C, because the transistors will act as
inverters.

The only other components required are 2 x 4k7 pullup resistors (and
obviously connections to two input lines on the printer port).

Regards,
SJH
Canberra, Australia

1996\12\19@020627 by nigelg

flavicon
picon face
In message  <KILLspam2.2.32.19961218170201.00958f9cspamBeGonespamwinning-edge.com>> EraseMEPICLISTspamEraseMEMITVMA.MIT.EDU writes:
> I'm working on some PIC devices and intend to use some I2C code to code up
> the slave routines.  I found routines to let me use PC parallel port as
> master to test my slave devices but the references I found all use some sort
> of hardware on the PC port such as a 74LS05 to aid in the bidirectional I2C
> implimentation. Since some of the parallax products seem to use I2C to talk
> between the PC and the target system without any extra hardware at the PC
> end, I was wondering if anybody had any info on how to do this.  The
> hardware is simple enough, I just was trying to avoid a trip to the city to
> get the parts for the I2C PC port interface.

I wouldn't have thought this possible, the SDA line has both input and output
on the same pin, and needs to connect to both an input and an output on the
PC port. The usual way of doing this is an open collector buffer (74LS07 etc.)
but a transistor and two resistors would do just as well. It might even be
possible to use just a single diode, cathode to output pin, anode to input
pin, and connect the input pin to the bus, make sure the output pin is high
when reading the bus. I've not tried it, but I don't see why it wouldn't work.

BTW, what parallax products use I2C to talk to the target system?.

Nigel.

       /--------------------------------------------------------------\
       | Nigel Goodwin   | Internet : @spam@nigelg@spam@spamspam_OUTlpilsley.demon.co.uk     |
       | Lower Pilsley   | Web Page : http://www.lpilsley.demon.co.uk |
       | Chesterfield    |                                            |
       | England         |                                            |
       \--------------------------------------------------------------/

1996\12\19@021250 by Werner Terreblanche

flavicon
face
> From: "Larry P. Thomas WA0GWA" <spamBeGonelpthomasspamKILLspamWINNING-EDGE.COM>
> I'm working on some PIC devices and intend to use some I2C code to
> code up the slave routines.  I found routines to let me use PC
> parallel port as master to test my slave devices but the references
> I found all use some sort of hardware on the PC port such as a
> 74LS05 to aid in the bidirectional I2C implimentation. Since some of
> the parallax products seem to use I2C to talk between the PC and the
> target system without any extra hardware at the PC end, I was
> wondering if anybody had any info on how to do this.  The hardware
> is simple enough, I just was trying to avoid a trip to the city to
> get the parts for the I2C PC port interface.

I haven't really checked what protocol the Parralax products use, but
I'm convinced it is not I2C.  The problem is that I2C requires a
bidirectional line for the SDA which can also be pulled low when the
slave device does an acknowledge.  That is why all implementations of
I2C on the PC parallel port usually require a little bit of external
hardware.

It is definetely possible to implement your own  serial protocol directly on
the parallel port because there are 5 input and many output pins on the PC
parallel port which you can interface to directly.  The outputs of
the PC printer port is given below.  The signals marked with a - are
inverted.  The ones who's direction are marked OUT, actually mean
that you can use them as inputs from your PC side.


FUNCTION        DIR     PRINTER 25 Way
-STROBE                    IN   1       1
-DATA 1                    IN   2       2
+DATA 2                    IN   3       3
+DATA 3                    IN   4       4
+ DATA 4                        IN      5       5
+ DATA 5        IN      6       6
+ DATA 6        IN      7       7
+ DATA 7        IN      8       8
+ DATA 8        IN      9       9
- SELECT                           IN   36      17
- AUTO LF       IN      14      14
- INIT                     IN   31      16
-ACK                       OUT  10      10
+BUSY                      OUT  11      11
+PAPER END      OUT     12      12
+SELECT                    OUT  13      13
-FAULT                     OUT  32      15
GND             19-30   18-25

I can recommend you try and get the IBM Parallel Port FAQ. This
FAQ is an excellent guide towards interfacing with the IBM PC
Parallel Printer Port.  It overcomes some of the IBM documentation
errors and has been compiled from a cross correlatation of various
sources including schematics to get a consistent and workable picture.
It all contains information about hardware pinouts, differences
between various types of adapted cards and lots of information about
the setting of the software registers etc. It was compiled by Zhahai
Stewart  <.....zstewartspam_OUTspamnyx10.cs.du.edu>

You can get it via email from <TakeThisOuTparport.....spamTakeThisOuThisys.com.>

There is a plain text version as well as an
HTML version of the FAQ available on the net. The plain ASCII version
is available at: <URL:ftp://ftp.rmii.com/pub2/hisys/parport>

Hypertext version:

  <URL:www.paranoia.com/~filipg/HTML/LINK/PORTS/F_PARALLEL1.html>
and
   <URL:http://rainbow.rmii.com/~hisys/parport.html>

More information on the Parallel Port available: Some more information on
hardware/software interfacing using the PC parallel (printer) port is
available from :

  <URL:http://purcell.ecn.purdue.edu/~epics/HW_SW_INT/slide1.html>

Additional information about the Parallel Port can be obtained from :

<URL:ftp://ftp.ee.ualberta.ca/pub/cookbook/comp/ibm/pport094.doc.Z>

And also at: <URL:ftp://ftp.armory.com/pub/user/rstevew> Look for the
files *lpt.faq; ibmlpt.faq, tomlpt.faq, and krislpt.faq

I hope that all these URL's are still valid, and that this info will
help.

Good luck
Werner

--
Werner Terreblanche     http://www.aztec.co.za/users/werner
TakeThisOuTwterrebKILLspamspamspamplessey.co.za (work)  OR  .....wernerspamRemoveMEaztec.co.za  (home)
Plessey SA, PO Box 30451, Tokai 7966, Cape Town, South Africa
Tel +27 21 7102251   Fax +27 21 721278   Cell +27 837255164
------------------------------------------------------------

1996\12\19@203036 by John Payson

picon face
> It is definetely possible to implement your own  serial protocol directly on
> the parallel port because there are 5 input and many output pins on the PC
> parallel port which you can interface to directly.  The outputs of
> the PC printer port is given below.  The signals marked with a - are
> inverted.  The ones who's direction are marked OUT, actually mean
> that you can use them as inputs from your PC side.

Note that [I'll have to see if the 'parallel port FAQ' documents this] on
most parallel-port cards, including the originals, the strobe, select,
auto-lf, and init outputs may all be used as open-collector bidirectional
signals (so the total is five dedicated inputs, eight dedicated outputs,
and four bidirectional).  This can be extremely convenient, esp. for the
RB7 'programming data' signal.  **BUT** some parallel ports, most notably
Toshiba laptops, do NOT support this.  If using these pins in a design
makes things easier, go ahead and do it (it will work on 99% of the PC's
out there) but be sure to DOCUMENT it and provide a workaround.

1996\12\20@130610 by Dwayne Reid

flavicon
face
>Otherwise, use a couple of small NPN's (2n2222) in common emitter/open
>collector mode - use resistor in base drive and invert the output
>levels from 'standard' I2C, because the transistors will act as
>inverters.

I missed the original question describing the problem.  Since a PIC can
drive I2C buss lines directly (by writing a 0 to the port pin and
controlling the appropriate TRIS bit to simulate an open collector (drain)
output), I'm assuming that you want to use something like a printer port to
drive I2C.

This is easy: first use a couple of 4K7 resistors as pullups from the port
pins to VCC to ensure that Vout HI goes all the way to 5V (early printer
ports use TTL output drivers).  To eliminate the forward drop of ordinary
silicon diodes, use a hi gain sgnal transistor (2n2222, 2n4401, 2n3904, etc)
and a 10K - 22K resistor connected as follows:  one side of resistor to VCC,
other side to base; emitter to Port o/p pin; collector to I2C buss line.
Repeat for the other buss line.  The basis for this is that the base
resistor holds the transistor in saturation for about 0.1 to 0.2 Vdc drop.
When the Port pin goes lo, so does the buss.  When the Port pin is hi, the
transistor base is at the same potential as the emitter and the transistor
is turned off.  Any other device pulling the buss lo does not affect the
Port pin.  BTW: you still need the 2 4K7 pullup resistors on the I2C buss lines.

This avoids the problems of both diode drop and signal inversion.

Dwayne

1996\12\21@003117 by John Payson

picon face
> I missed the original question describing the problem.  Since a PIC can
> drive I2C buss lines directly (by writing a 0 to the port pin and
> controlling the appropriate TRIS bit to simulate an open collector (drain)
> output), I'm assuming that you want to use something like a printer port to
> drive I2C.
>
> This is easy: first use a couple of 4K7 resistors as pullups from the port
> pins to VCC to ensure that Vout HI goes all the way to 5V (early printer
> ports use TTL output drivers).  To eliminate the forward drop of ordinary
> silicon diodes, use a hi gain sgnal transistor (2n2222, 2n4401, 2n3904, etc)
> and a 10K - 22K resistor connected as follows:  one side of resistor to VCC,
> other side to base; emitter to Port o/p pin; collector to I2C buss line.
> Repeat for the other buss line.

Hmm... one technique I've sometimes used which would seem apropos here is
to hook two inputs on the printer port up to the I2C bus, and connect them
also, through 4.7K resistors, to two printer port outputs.  Adding two
pullups between those outputs and +5 might not be a bad idea, but I've never
had to do that.

An alternative, which will work on 99% of PC's, is to simply use two of the
control output pins directly (pullups are probably a good idea here).  On
a standard parallel card, the control outputs are all open-collector and so
may be used bidirectionally.  Unfortunately, this does not work on Toshiba
laptops and it may fail on other machines as well.


'Please help me, my EPIC & my project!'
1997\03\20@233759 by Robert Russell
flavicon
face
I am the proud new owner of Sirius microSystems' PIC-MDS development
system and an EPIC pocket programmer.  I have run into one little snag
however: the EPIC has stopped working.  I think I may have inadvertantly
diddled with the variable resistor on the board - the one that is clearly
marked "DND" (Do Not Diddle) in some piece of documentation that I either
don't have or have overlooked in my haste.  You see, I have only a week
or two to finish my project, otherwise I would spend a little more time
investigating.
BTW: there is also an empty outline labelled R2 in parallel with the
potentiometer (this might just be a spot for the bonus resistor, I think
it was always empty on my board).

Thanks,
        Rob Russell
        RemoveMErussel4spamspamBeGoneserver.uwindsor.ca


'PIC & phone'
1997\04\02@090201 by Fabrice POPINEAU
flavicon
face
Hi,

Not directly related to PICs, but I'm building a phone transmitter
with a 16C84.

My problem: I'd like to phone somebody and to detect when the
callee has lift the receiver. Idea anybody ?

Thanks,


--
Fabrice POPINEAU
------------------------
e-mail:         spamBeGonepopineau@spam@spamspam_OUTese-metz.fr    |  "God is real ...
       TakeThisOuTFabrice.POPINEAUspamspamsupelec.fr     |
voice-mail:   +33 (0) 387764715         |          ... unless integer ?"
surface-mail: Supelec, 2 rue E. Belin,  |
             F-57078 Metz Cedex 3      |

1997\04\02@093943 by gplummer

flavicon
face
> Hi,
>
> Not directly related to PICs, but I'm building a phone transmitter
> with a 16C84.
>
> My problem: I'd like to phone somebody and to detect when the
> callee has lift the receiver. Idea anybody ?
>
> Thanks,

> Fabrice POPINEAU

Hi,

If i've understood you're requirements:

Firstly, you'll need a line interface which depends on the country of
use and you may well have to gain approval to attach to the local
phone system.

Secondly, use a dtmf encoder (Most major semis do 'em, look on web
for circuits) to dial which will easily interface to PIC's.

Thirdly, you'll need some filters to detect tones. ie engaged tone,
ringing tone. If you detect ringing tone and then it disappears
someone's answered. Better system will look for engaged tone and give
up for a while and retry later.

Regards,
Greg Plummer

1997\04\02@102506 by gplummer

flavicon
face
> Hi,
>
> Not directly related to PICs, but I'm building a phone transmitter
> with a 16C84.
>
> My problem: I'd like to phone somebody and to detect when the
> callee has lift the receiver. Idea anybody ?
>
> Thanks,
>
> Fabrice POPINEAU
>
Hi,

If i've understood you're requirements:

Firstly, you'll need a line interface which depends on the country
of  use and you may well have to gain approval to attach to the
local phone system.

Secondly, use a dtmf encoder (Most major semis do 'em, look on web
for circuits) to dial which will easily interface to PIC's.

Thirdly, you'll need some filters to detect tones. ie engaged tone,
ringing tone. If you detect ringing tone and then it disappears
someone's answered. Better system will look for engaged tone and
give up for a while and retry later.

Regards,
Greg Plummer

1997\04\03@183356 by gjenkins

flavicon
face
Fabrice POPINEAU wrote:
>
> Hi,
>
> Not directly related to PICs, but I'm building a phone transmitter
> with a 16C84.
>
> My problem: I'd like to phone somebody and to detect when the
> callee has lift the receiver. Idea anybody ?
>
> Thanks,
>
> --

The CML FX623 Call Progress Tone Decoder does it all for you.

Geoff


'PIC & LCD'
1997\05\29@090914 by Eric Martens
flavicon
face
Hello Guys

I have a little problem, it is not the normal stuff for this mailing list
so
i'll try
to keep it as short as possible I have two very nice LCD's in my
possession, one 2
x 32 characters and one 4 x 32 characters. I'm designing an audio control
center and i want to use one of these two LCD's. Preferable the 4 x 32
characters. I'm using a PIC 16C62 to control the audio center. I'm first my
gathering al the datasheets of the components i'm using. But i don't have
the datasheets of the LCD's. I can't remember where i got the LCD's from
and there is no manufactures name on them. On the back of the 4 x 32 LCD
there are two numbers: M3214 and F1632 separated by a slash (/). I don't
now if this rings a bell with any of you ???

The only thing i know for sure is that both the LCD's use the same
controller or better said controllers. the 4 x 32 has 8 of them and the 2 x
32 has 4 of them. The Controller i'm talking about is the D7227G from NEC
in Japan. From the number of controllers on the LCD's and the shape of the
characters i conclude that it is a 16 character controller consisting of 16
x 5  kolom drivers and 8 row drivers (7 for the characters and one to
underline the characters).

Does anyone reconize these LCD's ? Do you know the processor ? I'm
interested in character tables, datasheets, end so on. Any help would be
much appriciated. I have tried it with NEC in Japan but like all other
japanese manufactures they don't reply to your questions if your not a bulk
user.

I hope someone can help me otherwise i'll be forced to buy new LCD's and in
that size there not cheap !!!!


Greetings Eric Martens

***************************
*  Eric Martens           *
*  emarEraseMEspamknoware.nl  *
**************************

1997\05\29@104713 by Wayne Bennett

flavicon
picon face
Can't really help that much but the M3214 sounds like a Seiko Instruments
model number.  I've just spent about two weeks on the net trying to find
data sheets on LCD modules and haven't had hugh amounts of luck, try farnell
you might get lucky.

The 4x32 display sounds similar to one a friend was using, I'll check with
him and get back as soon as I can, email be if you don't hear back in the
near future.

Sorry I could be more helpful.
        _/       _/      _/_/_/_/
       _/       _/      _/     _/
      _/       _/      _/     _/
     _/  _/   _/      _/_/_/_/
    _/ _/ _/ _/      _/      _/
   _/_/   _/_/      _/      _/
  _/       _/  _/  _/_/_/_/

Wayne Bennett
Griffith University
Brisbane Australia
RemoveMEw.bennettEraseMEspamspam_OUTsct.gu.edu.au

'PIC & LCD LCD interfaces'
1997\05\29@154715 by wft

face
flavicon
face
Most LCD interfaces are virtually the same.  Try getting data at the
following locations:
http://www.hantronix.com:80/
http://www.ieeinc.com/
http://www.lukin.com.hk:80/SII/lcd.htm


hope these help

Gus
--
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
WFT Electronics    @spam@wftRemoveMEspamEraseMEfrii.com   http://www.frii.com/~wft
Gus Calabrese      303 321-1119......voicemail
Lola Montes        1799 Uinta Street   Denver, CO 80220
EMERGENCY:   791 High Street     Estes Park, CO  80517
if no success with EraseMEwftspam@spam@frii.com, try .... @spam@wftspam_OUTspam.....bigfoot.com

1997\05\30@054432 by Paykar Chamani

flavicon
face
part 0 2051 bytes
There is an interesting web site to check :
www.paranoia.com/~filipg/HTML/LINK/F_Tech_LCD.html
I hope it will be helpful for you.

{Original Message removed}


'PIC & EPROM'
1997\09\30@081919 by courche
flavicon
face
Hello,

My name is christophe, i'm french

For the moment i use PIC with the PIC basic by Forest Electronic dev.

Now i want to devellop with C or other compiler directy to PIC.

I seach a method to program PIC without use of internal EPROM. I seach a
method to produce the code into an EEPROM like 28C64 and PIC can execute
the prog whitch burns into the EEPROM... I d'ont whant to use 10 PIC to
debug final program and wait for the EPROM eraser after my 10 PIC was
burned !.

The solution with the EEPROM or serial eprom is just a idea... Have you got
other idea or other methods to devellop without PIC simulator or PIC
internal EPROM ?

Thanks for your help...

Christophe

1997\09\30@115541 by Mike Keitz

picon face
On Tue, 30 Sep 1997 14:01:44 +0200 courche <spamBeGonecourcheEraseMEspamCHEZ.COM> writes:

>I seach a method to program PIC without use of internal EPROM. I seach
>a
>method to produce the code into an EEPROM like 28C64 and PIC can
>execute
>the prog whitch burns into the EEPROM... I d'ont whant to use 10 PIC
>to
>debug final program and wait for the EPROM eraser after my 10 PIC was
>burned !.

Only the PIC17Cxx chips can execute from external program memory.  The
vastly more popular and less expensive 16XX line doesn't.  You can use a
PIC16F84, which has internal EEPROM program memory so it can be reused
immediately.  Put your first few projects in with 16F84's to become
familiar with direct to PIC programming.

This works fine until you need the extra pins or features of some other
PIC16CXX.  The other PIC16's have EPROM program memory, which must be
erased with UV light.  I've found it effective to cycle 3 erasable PICs
through programming and erasing.  One PIC is in the circuit while the
other 2 are in the UV eraser.  Set the timer on the eraser to slightly
longer the minimum time it takes to make a PIC "blank".  With a good new
eraser this is about 3 minutes.  When you need to try a new program, take
the PIC out of the circuit and put it in the eraser, take out the PIC
which has been in the eraser the longest (which has been erased twice so
it is reasonably reliably blank) and use it.  When the erase cycle is
done the other PIC in the eraser has been erased fully, the one just put
there only once.  This way you have access to a blank PIC about every 3
minutes.  Obviously, "pipelining" more PICs in the eraser could speed up
the process even more but 3 minutes is about right.


'PIC & EPROM'
1997\10\01@102618 by mikesmith_ozNOSP*M
flavicon
face
> On Tue, 30 Sep 1997 14:01:44 +0200 courche <courchespamBeGonespamCHEZ.COM>
> writes:
>
> >I seach a method to program PIC without use of internal EPROM. I seach
> >a
> >method to produce the code into an EEPROM like 28C64 and PIC can
> >execute
> >the prog whitch burns into the EEPROM... I d'ont whant to use 10 PIC
> >to
> >debug final program and wait for the EPROM eraser after my 10 PIC was
> >burned !.

If you don't have a real 'need for speed' then use an interpreter -
the interpreter lives in the on-chip eprom, and interprets the serial
io eeprom.  There's a C one of these available - my www browser is
not available, or I'd tell you where to look, but start at the ormix
site.
MikeS
<mikesmith_ozNOSP*M.relaymail.net>
(remove the you know what before replying)

'ICEPIC & ICE in general'
1997\10\08@201813 by Andy Shaw

flavicon
face
Hi Folks,
I've just got hold of an ICEPIC and a really nice tool it is. It certainly
speeds up my development process (no more program chip, test,
fix erase program cycles). Anyway just a few thoughts am I the
only one that finds the mplab watch windows a real pain why only
one var per window and why can't you treat a byte as an 8 bit
signed value! The native ICEPIC tool is much nicer for this sort of
thing (though I really like the conditional break stuff), but I use the
Picstart plus and I don't see any way to drive that without using
mplab. Anyone know if this is possible.

Oh one final thing. Having used this I'm curious as to how it works.
I can see that the daughter board has two chips, one seems to be
some sort of PIC core the other the IO devices. But how are the
internal parts of the device exposed, what sort of operations are
supported. Anyone know?

Andy

1997\10\08@204708 by Andy Kunz

flavicon
face
>Oh one final thing. Having used this I'm curious as to how it works.
>I can see that the daughter board has two chips, one seems to be
>some sort of PIC core the other the IO devices. But how are the
>internal parts of the device exposed, what sort of operations are
>supported. Anyone know?

That's all "non-disclosable" information.  You can gain a good
understanding, though, by studying how you connect different chips
(6x/7x/8x, etc) from a family (16C01/16C02) if you study the Tech-Tools
catalog a little bit.

Andy

==================================================================
Andy Kunz - Montana Design - 409 S 6th St - Phillipsburg, NJ 08865
         Hardware & Software for Industry & R/C Hobbies
       "Go fast, turn right, and keep the wet side down!"
==================================================================

1997\10\09@014305 by tjaart

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Andy Shaw wrote:
>
> Hi Folks,
> Oh one final thing. Having used this I'm curious as to how it works.
> I can see that the daughter board has two chips, one seems to be
> some sort of PIC core the other the IO devices. But how are the
> internal parts of the device exposed, what sort of operations are
> supported. Anyone know?
>
> Andy

As I have it, _all_ the PICs have bond-out connections on the silicon.
To make a bond-out PIC, Mchip connects up the pads, put it in an
expensive carrier and then charge you 20 times the price.

--
Friendly Regards

Tjaart van der Walt
RemoveMEtjaart@spam@spamspamBeGonewasp.co.za
_____________________________________________________________
| WASP International http://www.wasp.co.za/~tjaart/index.html |
|       R&D Engineer : GSM peripheral services development    |
|   Vehicle tracking | Telemetry systems | GSM data transfer  |
|    Voice : +27-(0)11-622-8686 | Fax : +27-(0)11-622-8973    |
|              WGS-84 : 26010.52'S 28006.19'E                 |
|_____________________________________________________________|

1997\10\09@095643 by Darrel Johansen

picon face
Andy Shaw wrote:
>

> I've just got hold of an ICEPIC and a really nice tool it is. It certainly
> speeds up my development process (no more program chip, test,
> fix erase program cycles). Anyway just a few thoughts am I the
> only one that finds the mplab watch windows a real pain why only
> one var per window and why can't you treat a byte as an 8 bit
> signed value!

When the watch window has the focus, press the "Insert" key (or pull
down the system menu --the top left button on the watch window) to add
additional variables.

Darrel

1997\10\09@142317 by jorgegf

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Hi

...
> only one that finds the mplab watch windows a real pain why only
> one var per window and why can't you treat a byte as an 8 bit
> signed value! The native ICEPIC tool is much nicer for this sort of
> thing (though I really like the conditional break stuff), but I use the
...
>
> Andy
...

       One var per window ???. Only if its the release you are using. Just
downloaded mplab 3.30 and a tutorial and as simply as they say around
page 13, and I quote [ 7. Enter the variable "Countdown" and click OK
[...] If you want to add another variable to the watch window ... ].
       To me it worked well with the tree variables of the "tutor.asm" file
used in this example.
If yoy are running an older release it might be interesting to check
Microship's web site http://www.microship.com.


       best regards

       Jorge F

1997\10\09@182616 by Christof

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On  9 Oct 97 at 18:25, Jorge Ferreira wrote:

>         One var per window ???. Only if its the release you are using. Just
> downloaded mplab 3.30 and a tutorial and as simply as they say around
> page 13, and I quote [ 7. Enter the variable "Countdown" and click OK
> [...] If you want to add another variable to the watch window ... ].

True! >INS< let you select additional variables. MPLAB helps you select
variable names as you start typing initial letters.

> Microship's web site http://www.microship.com.

That's an interesting WEB site!! If you don't succeed use ...MICROCHIP.COM

Christof   ;-)
>
>


'PIC & Motorola's OPTOBUS'
1997\12\15@221433 by Pablo
picon face
Hi,

I'm working on a new project where I need to link to PICs via fiber
or plastc fibre. I get some information on OPTOBUS by Motorola and on
TAXI Chip by HP.
Actually I've all the appropiate information for the development. But
I would like to know if anybody on the list have some experiences on
this subjects. I'll appreciate any kind of comments.

Thanks in advance.

Pablo Mochcovsky

1997\12\16@104155 by Mcorio

picon face
In a message dated 97-12-15 23:38:28 EST, you write:

<<
I'm working on a new project where I need to link to PICs via fiber
or plastc fibre. I get some information on OPTOBUS by Motorola and on
TAXI Chip by HP.
Actually I've all the appropiate information for the development. But
I would like to know if anybody on the list have some experiences on
this subjects. I'll appreciate any kind of comments.

Thanks in advance.

Pablo Mochcovsky
 >>

TAXI Chip is an AMD part and runs at approx 50MHz (if I remember correct).
This is likely to be way too fast (or at least overkill) for the PIC.

Mark A. Corio
Rochester MicroSystems, Inc.
200 Buell Road, Suite 9
Rochester, NY  14624
Tel: 716-328-5850
Fax: 716-328-1144
http://www.frontiernet.net/~rmi/
****** Designing Electronics for Research and Industry ******

1997\12\16@161447 by paulh

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face
[I sent this once before, but the posting went to listserv, rather than
piclist.  My apologies if this goes out twice.  I've trimmed the quoted
text for try 2.]

I'm using IF-D91 photodiodes and IF-E91B LEDs made by "Industrial Fiber
Optics".  They mate with standard 1000 micrometer plastic fiber cable.
The LED's and photodiodes have built in lens and connector housings.  You
cut the fiber with a hot knife and stick it into the LED and tighten the
nut, no other hardware required, no polishing required.

These parts work fine at slow speed like 9600 baud, with just current
limiting and pull-up resistors.  That's all I need.  They'll go somewhat
faster, but not anywhere near 50Mhz.

I'm using duplex fiber, which is 2 fibers stuck together like zip cord.
I've run some out to my hottub (http://www.hamjudo.com/cgi-bin/hottub).
This will let me do fancier stuff without the risk of electrocution.
(I'll get around to updating the write up eventually.)

I got the fiber, photodiodes and LEDs from Circuit Specialists Inc.
(http://www.cir.com). Digikey also sells the stuff except for the duplex
fiber (http://www.digikey.com).  In quantity 10, Circuit Specialists
charged me $2.40/meter for the duplex fiber, $3.02 for each photodiode and
$2.37 each for the LEDs.  The hot knife was $19.95 (it is a soldering iron
handle which holds Xacto blades).

I'd like to send power down the fiber too.  Anyone know where to get solar
cells designed to work with fiber?  It seems easy to get a lot of light
energy into the fiber, but much more complex to get that back out at the 3
or so volts that a LC PIC needs.

--
.....paulh@spam@spamEraseMEhamjudo.com  http://www.hamjudo.com
The April 97 WebSight magazine describes me as "(presumably) normal".


'PIC & X10 generation questions'
1998\01\02@135933 by n/a
flavicon
face
I've taken some interest in working on sending and receiving
X10 signals. That is 120KHz frequency pulses over 60Hz carrier.

Does anyone have any references or pointers to sample code?
(Doesn't have to be X10 just frequency generation and reading)

Also what PIC would you recommend?

--
Thanks
Neil Cherry


'Pic & JOb'
1998\05\08@112015 by Haile, Sam
flavicon
face
Hi All

can someone find a job with... pic programming knowledge only... or
learning to program pic is not meant for job just for fun


sam

1998\05\08@174328 by Bill Cornutt

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face
----------
> Hi All
>
> can someone find a job with... pic programming knowledge only... or
> learning to program pic is not meant for job just for fun
>
>
> sam
>


Sam,

Your question in interesting.

Programming is the art of solving problems using strict rules.
Every language and microprocessor has slightly different rules.
So Your question may be stated as "If I only learn one set of rules,
can I get a job?"

I am interested in art.  I have limited myself to using green
watercolor and painting the leaves of flowers.  Needless to
say, even though my paintings are true reproductions of
various green leaves, I have not sold many paintings.

With programming, not only do you need to know the rules, but you
need to be able to solve problems.  To learn the rules of a
language you need to write programs.  And with every program you
will get better.  And with solving problems, the same applies.  You
need to write programs and solve the problems as they come up.

School is a great way to learn.  The courses have been designed to
guide you through the learning process and the instructor is there
to help you when you have a problem.  Also your class mates will
be a help when you sit around and talk to them.  But it is up to you
to learn.  Don't just complete the assignments, try to make them
the best you can.  And write programs on your own that are not
assigned in class.  Program, program, program.....

The pic is not the best place to start.  It is complicated and there
is nothing more flustratting then to spend days trying and not
accomplish anything.  I would suggest that if you have no
experience programming, that you start with Qbasic.  Qbasic will
allow you to start out with simple programs and as your skill
increases, you can use the more advance features and build on
your knowledge.

I have not answered all of your questions, but others will have
advice also.

Bill C   .....billRemoveMEspamcornutt.com

1998\05\08@180221 by Calvin

flavicon
face
Ha!

Is this a joke, or what?

Calvin

-----Original Message-----
From: Haile, Sam <.....shaileSTOPspamspam@spam@ESEC1.ESSEX.AC.UK>
To: PICLISTEraseMEspam@spam@MITVMA.MIT.EDU <RemoveMEPICLISTspamspamBeGoneMITVMA.MIT.EDU>
Date: Viernes 8 de Mayo de 1998 10:13 AM
Subject: Pic & JOb


>Hi All
>
>can someone find a job with... pic programming knowledge only... or
>learning to program pic is not meant for job just for fun
>
>
>sam
>

1998\05\08@184849 by William Chops Westfield

face picon face
> can someone find a job with... pic programming knowledge only... or
> learning to program pic is not meant for job just for fu

"pic programming knowlege only" is not enough to get a job, IMHO.

First of all, "programming knowlege only" is pretty limitting.  In
general, it is more important to understand the problem you are solving
with your "program" than the programming itself.  This is why you can
find people with PHd's in computer science who are useless; unless you
happen to need something that exactly coincides with their thesis and
the environment they produced it in.  Since a PIC itself is so tiny and
pointless (unlike a desktop PC, for example), you have to know a fair
amount about the sort of things it can connect to.

Secondly, knowlege about a single particular architecture is limitting.
If you have a thorough knowlege of the PIC architecture(s) and
programming, you should have picked up enough about OTHER architectures
and languages to claim better than "PIC only."  If not, perhaps there is
something wrong with you.

There are probably some short term or "consulting" niches for someone
who doesn't do anything except PIC programming.  Probably NOT something
long term "that pays better than McDonalds" (over a long timeframe), or
with much of a "career growth path."

All those negatives aside, the "hands on hardware" knowlege of a typical
crop of "computer science BS's" is pretty abysmal, and the person who
built an 16C84 "LED blinker" will get the job offer over the otherwise
equal person who didn't, at least from me.

This is also, IMHO, what makes this such a good mailing list.  The scope
of discussion goes far enough beyond the PIC itself to make it almost
"well rounded"...

BillW

1998\05\08@191158 by Wynn Rostek

flavicon
face
>> Hi All
>>
>> can someone find a job with... pic programming knowledge only... or
>> learning to program pic is not meant for job just for fun

Sam,

PIC's are not just for fun, they are used in thousands of products.

As for getting a job knowing only how to program PIC's, I would have to say
that your chances are very slim.

If you would bear with me for a moment, I'd like to give you a different
slant on your question.  Medical knowledge spans a fairly wide range.  On
the low end, a boy scout may get a merit badge in first aid.  There are
paramedics, nurses, medical researchers, family doctors, surgens, and brain
surgens.

Brain surgens make a lot of money, and you don't see too many out of work
brain surgens.  On the other hand, I have not seen too many jobs that
required a merit badge in first aid.

Knowing how to program a single family of processors is like a merit badge.
You gain useful knowledge, but you are not likely to get a job because of it.

I have programmed in over a dozen high level languages, and I've programmed
in assembly language for over 20 processors.  The language is like a kind
of wood.  You can build a book shelf out of pine, or oak, or walnut.  Each
type of wood is a little different, and you have to handle them a little
different, but it is still a book shelf.  An employer cares a lot more
about about your knowledge of how to build a book shelf or a set of
cabinets than how much you know about a certain type of wood.

At least here in the United States, you can make a reasonable living with a
two year degree in computer programming.  You will make a little less than
twice as much with a four year degree, so if you can make it through
calculus and physics, it's worth it in the long run.

Just my two cents worth.  By the way, I have a BSCS in computer
architecture and I've been programming for 20 years.  I've also done
digital and analog design, and have a fairly broad background in RF. I also
made a living writing magazine articles for a while.  Just to let you know
how I've formed my opinions.

Wynn

1998\05\08@192227 by Mark S.

flavicon
face
This makes me feel good - I am a "average" pic programmer, though i have
done lots of programming (databases mostly). However, I am quite good with
electronics, that's my main passion.


{Quote hidden}

1998\05\08@213917 by robert bowman

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BillW said

>All those negatives aside, the "hands on hardware" knowledge of a typical
>crop of "computer science BS's" is pretty abysmal

one thing to beware: once your organization finds out you can actual get a
custom LCD to work or something, you will be writing drivers for the rest of
your life. kiss those sexy GUI jobs goodbye. personally, I figure a couple
of buttons is all the interface a sane user needs.

1998\05\11@122529 by Keith Howell

flavicon
face
Sam,

This posting has provoked far more responses than perhaps it requires.

I'll assume from the grammar and the surname that English is not
your first language, and allow for that.

> can someone find a job with pic programming knowledge only
> or [is] learning to program pic is not meant for job just for fun [?]

Well, all I do is program the PIC16C65 all day but if this were the only
skill I had then it would be hard to get any other job.

Skills cross-pollinate and blossom in novel ways.
Appreciating both hardware and software allows you
to design each with the other in mind.
My technical authoring skills allow me to prepare
project proposals and technical reports well.
A hobby interest in astronomy and satellites got me a job
offer with a company writing satellite mission control
software.

Regarding fluent English, this is essential if you wish to work
with English-speaking engineers. I certainly would find it
extremely hard to work in say France without being fluent in French.

Regarding spelling, an occasional slip of the finger is forgivable,
but when people repeatedly mis-spell the same word it is obvious they
don't know how to spell it. Acceptable for those learning a language,
but not for native speakers. If someone is not able to spell in their
own language, or is too sloppy to care about details, then I would
not employ them to produce good quality work. The comment about
mis-spelt variable names holds true.

Learn as many skills as your ability allows.
Each is a potential meal ticket!

"The roots of education are bitter, but the fruits are sweet"
- some ancient greek philospher.

1998\05\13@110835 by lilel

flavicon
face
Kieth wrote:


> Skills cross-pollinate and blossom in novel ways.
> Appreciating both hardware and software allows you
> to design each with the other in mind.
> My technical authoring skills allow me to prepare
> project proposals and technical reports well.
> A hobby interest in astronomy and satellites got me a job
> offer with a company writing satellite mission control
> software.

Like kieth, I program PICs day in and day out, but I could not do my
job without other skills:

Mountain climbing skills got me a job fixing alarm systems on top of
tall, tall storage tanks.  With a few ropes and a voltmeter I could
climb much more safely and efficiently than the other techs.

Experience in HVAC controls got me a lot of knowledge in heat
transfer and eventually led  to a job with an appliance company
making things that heat food.

Playing around with PICS making LED blinkies and other simple
circuits led to job programming them.  "CAN YOU PROGRAM
MICROPORCESSORS?" they asked.  "YUP!" I said, gulping.  "THEN HERE"S
YOUR BENCH!" they said.  "Oh SH___" I thought, expletive deleted,
"Now I'll have to do this for real!"


Best Regards,

Lawrence Lile

1998\05\13@221953 by ape

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This reminds me of the lessons of my computer teacher years ago.  He
would
drill it into our heads in the first week that programming within itself
is absolutely
worthless.  One of the examples he used was to ask us, "If you knew how
to
program, could you write a chess program if you don't even know how to
play
chess?" (he gave other examples).

I personally haven't done programming of any sort in years.  I instead
went back
to school, got my 2 year electronics degree, got some experience, and am
now
getting back into programming.  My specialty is programming MCU's to
replace
preexisting circuits into a much smaller and cheaper package.  But I
have to
understand the electronics that I'm replacing.

Lawrence Lile wrote:

{Quote hidden}

1998\05\13@234911 by Chuck Rice

flavicon
face
At 9:21 AM -0700 5/11/98, Keith Howell wrote:

> If someone is not able to spell in their
> own language, or is too sloppy to care about details, then I would
> not employ them to produce good quality work. The comment about
> mis-spelt variable names holds true.


This has not been my experience. There are many types of engineers.
In my experience, the creative spellers also tend to be creative
engineers. The spelling 'bean counters' also make good engineers,
but of a different type. I have found that it is good to have both
types on staff.

By being prejudice against one type or the other, you cut yourself
off. You can hire a minimum wage worker to edit and respell the
poor spelling engineers work, but you cannot hire a minimum wage
design engineer to create for the good speller.

Sometimes you can find the all around perfect person, but they are
few and far between.

As a job applicant, you should put your best foot forward and
spell check your work and go the extra mile. But as an employer,
you should keep an open mind and judge on the employees worth
to the company.  -Chuck-

__________________________________________________________________________
Chuck Rice                                     <spamBeGoneChuckKILLspamspam@spam@WildRice.com>

'Pic & JOb '
1998\05\15@104406 by lilel

flavicon
face
My best technician came from Nigreria.  Can't spell worth a durn or
write a legible sentence either.

Writing code makes you a good speller -but only in Assembly language
or C, not English or Swahili!




{Quote hidden}

Best Regards,

Lawrence Lile


'Pic & EEPROM PROGRAMMER'
1998\08\17@192021 by Jazz
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part 0 730 bytes
<META content=text/html;charset=iso-8859-1 http-equiv=Content-Type>
<META content='"MSHTML 4.72.3110.7"' name=GENERATOR>
</HEAD>
<BODY bgColor=#ffffff>
<DIV><FONT color=#000000 size=2><A
href="http://www.geocities.com/SiliconValley/Grid/3119/index.html">www.geocities.com/SiliconValley/Grid/3119/index.html</A></FONT></DIV>
<DIV><FONT color=#000000 size=2></FONT>&nbsp;</DIV>
<DIV><FONT size=2>this is a neat programmer worth a look </FONT></DIV>
<DIV><FONT size=2></FONT>&nbsp;</DIV>
<DIV>&nbsp;</DIV></BODY></HTML>

</x-html>

1998\08\17@192021 by Jazz

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part 0 730 bytes
<META content=text/html;charset=iso-8859-1 http-equiv=Content-Type>
<META content='"MSHTML 4.72.3110.7"' name=GENERATOR>
</HEAD>
<BODY bgColor=#ffffff>
<DIV><FONT color=#000000 size=2><A
href="http://www.geocities.com/SiliconValley/Grid/3119/index.html">www.geocities.com/SiliconValley/Grid/3119/index.html</A></FONT></DIV>
<DIV><FONT color=#000000 size=2></FONT>&nbsp;</DIV>
<DIV><FONT size=2>this is a neat programmer worth a look </FONT></DIV>
<DIV><FONT size=2></FONT>&nbsp;</DIV>
<DIV>&nbsp;</DIV></BODY></HTML>

</x-html>

1998\08\18@040119 by Jim Robertson

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<x-rich>At 01:19 18/08/97 +0200, you wrote:

>>>>

<excerpt>www.geocities.com/SiliconValley/Grid/3119/index.html
this is a neat programmer worth a look

</excerpt><<<<<<<<


Well it may be but the claim "The only Pic Programmer Which handles all
Microchip devices" sucks given it's current state of development and the
more extensive support available with other 3rd party programmers and the
PROMATE.


Jim



--------------------------------------------------------

Jim Robertson

NEWFOUND ELECTRONICS

Email: newfoundspam_OUTspam@spam@pipeline.com.au

http://www.pipeline.com.au/users/newfound

--------------------------------------------------------

</x-rich>

1998\08\18@115927 by Frans Gunawan

flavicon
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>From:         Jim Robertson <spamBeGonenewfound@spam@spamPIPELINE.COM.AU>
>Subject:      Re: Pic & EEPROM PROGRAMMER
>To:           RemoveMEPICLISTEraseMEspamKILLspamMITVMA.MIT.EDU
>
>At 01:19 18/08/97 +0200, you wrote:

>>>>

<excerpt>www.geocities.com/SiliconValley/Grid/3119/index.html
>this is a neat programmer worth a look

</excerpt><<<<<<<<


>Well it may be but the claim "The only Pic Programmer Which handles all
>Microchip devices" sucks given it's current state of development and the
>more extensive support available with other 3rd party programmers and the
>PROMATE.

yeah, I think you should delete the word 'the only' and 'Microchip devices'.
Don't you that Microchip has EPROM&EEPROM? Does your prog support that?
Don't you know that there are many 3rd party can do that?

http://www.poboxes.com/f
f


'PIC & SMS GSM'
1998\11\03@073611 by cacciavite
flavicon
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Hi PICer,

I have been a request to send an SMS GSM when certain phisical fact happens
(alarms, door switch , ecc).

This seems a perfect application for PIC, but I am now more confused about
the best and cheap way to comunicate to the cellular phone.

Do you know what is the best and cheap GSM telephone suited for this kind of
application??

Thanks for your suggestion.

Ciao

Leonardo

1998\11\03@082811 by tjaart

flavicon
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cacciavite@bigfoot.com wrote:
>
> Hi PICer,
>
> I have been a request to send an SMS GSM when certain phisical fact happens
> (alarms, door switch , ecc).
>
> This seems a perfect application for PIC, but I am now more confused about
> the best and cheap way to comunicate to the cellular phone.
>
> Do you know what is the best and cheap GSM telephone suited for this kind of
> application??
>
> Thanks for your suggestion.

There are five ways to do it :
1) Open up a phone, hack the communication bus, and connect a PIC.
  Advantages : You can get a phone from your corner store
  Disadvantages : You violate the full type approval (FTA) required
  to operate on any GSM network. A phone is also way unstable,
  because it was designed to be switched off/on every day.
  This is guaranteed to get you into trouble.

2) Get a GSM modem with FTA and CE. Connect this to your PIC.
  Advantages : You get FTA, the full command set, and support.
  The modem is also cheaper than a phone. Some modems (like
  ours - grin) are designed to stay switched on. A PIC12C508
  on the board does some general housekeeping to protect you
  from runaway situations. You can use the modem's power
  supply (6V 1A) to power your application. You also get an
  application to help you get going with SMS. Mounting the
  device is also easier if you have real mounting holes!
  Disadvantages : You can't buy one in the corner store.

3) Buy a ready product with FTA, CE and system/database software
  that can do for you what you want.
  Advantages : We already have a proven GSM based product that
  has 4 inputs, 2 relay outputs, and 3 open collector outputs.
  (It's driven by a PIC16C77) You don't need any development.
  Disadvantages : You can't buy one in the corner store.

4) Buy a GSM development platform.
  Advantages : You get processor time to add your own functionality.
  Disadvantages : The development system is very expensive. There
  is an extremely steep learning curve. You are on your own with FTA.

5) Buy a GSM engine and connect it to your PIC.
  Advantages : You could save a few bucks per unit if you buy
  in bulk.
  Disadvantages : You have to get FTA (US$100 000 per design).
  You also have to buy a pile of them at a time to get any
  discount. You have to go through a steep learning curve to
  get your PCB design to work OK, and to pass CE.

We can help you with options 2,3, and 5 (>100k quantity).

For quantities 1-1000 option 2) is easier and cheaper to start off.
For quantities 1000-50000 option 3) may be better.
For quantities >50000, option 5 is best.

If you want to have a look at the modem, go to
http://www.wasp.co.za/~tjaart/gcomspecs.html

If you want more info on the ready-made product in Europe, you
could also have a look on our swedish partner's web page at
http://www.cellpt.com/

--
Friendly Regards          /"\
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|--------------------------------------------------|
|                WASP International                |
|R&D Engineer : GSM peripheral services development|
|--------------------------------------------------|
|SMS .....tjaartspamRemoveMEsms.wasp.co.za  (160 chars max)|
|     http://www.wasp.co.za/~tjaart/index.html     |
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|--------------------------------------------------|

1998\11\03@185554 by Tim Modra

flavicon
face
Have been playing with this recently, primarily sending over temperature
alarms to GSM phones via SMS messaging.  This can be implemented at the most
basic level with a DS1820, PIC, 232 driver and a modem.  I've included LCD
for entry of nos. to send message to and temperature limits.

Have a search for +SMS +"TAP protocol".

Also, many pagers use this same protocol.

Any other info required, get me off list timspam@spam@modra.com.au


Tim Modra

{Original Message removed}

1998\11\03@193551 by Dennis Plunkett

flavicon
face
At 10:51 4/11/98 +1100, you wrote:
>Have been playing with this recently, primarily sending over temperature
>alarms to GSM phones via SMS messaging.  This can be implemented at the most
>basic level with a DS1820, PIC, 232 driver and a modem.  I've included LCD
>for entry of nos. to send message to and temperature limits.
>
>Have a search for +SMS +"TAP protocol".
>
>Also, many pagers use this same protocol.
>
>Any other info required, get me off list EraseMEtimRemoveMEspamSTOPspammodra.com.au
>
>
>Tim Modra
>
>{Original Message removed}

'R: Re: PIC & SMS GSM'
1998\11\04@062224 by Leonardo De Palo

flavicon
face
Hi, Tjaart

many thanks for your more exaustive answer. I have send EMAIL to your
colleague for pricing.


Ciao


Leonardo De Palo

-----Messaggio originale-----
Da: Tjaart van der Walt <RemoveMEtjaartKILLspamspamTakeThisOuTwasp.co.za>
A: spamBeGonePICLISTspam@spam@MITVMA.MIT.EDU <RemoveMEPICLISTspam_OUTspamMITVMA.MIT.EDU>
Data: marted“ 3 novembre 1998 14.28
Oggetto: Re: PIC & SMS GSM


cacciavitespamspambigfoot.com wrote:
>
> Hi PICer,
>
> I have been a request to send an SMS GSM when certain phisical fact
happens
> (alarms, door switch , ecc).
>
> This seems a perfect application for PIC, but I am now more confused about
> the best and cheap way to comunicate to the cellular phone.
>
> Do you know what is the best and cheap GSM telephone suited for this kind
of
> application??
>
> Thanks for your suggestion.

There are five ways to do it :
1) Open up a phone, hack the communication bus, and connect a PIC.
  Advantages : You can get a phone from your corner store
  Disadvantages : You violate the full type approval (FTA) required
  to operate on any GSM network. A phone is also way unstable,
  because it was designed to be switched off/on every day.
  This is guaranteed to get you into trouble.

2) Get a GSM modem with FTA and CE. Connect this to your PIC.
  Advantages : You get FTA, the full command set, and support.
  The modem is also cheaper than a phone. Some modems (like
  ours - grin) are designed to stay switched on. A PIC12C508
  on the board does some general housekeeping to protect you
  from runaway situations. You can use the modem's power
  supply (6V 1A) to power your application. You also get an
  application to help you get going with SMS. Mounting the
  device is also easier if you have real mounting holes!
  Disadvantages : You can't buy one in the corner store.

3) Buy a ready product with FTA, CE and system/database software
  that can do for you what you want.
  Advantages : We already have a proven GSM based product that
  has 4 inputs, 2 relay outputs, and 3 open collector outputs.
  (It's driven by a PIC16C77) You don't need any development.
  Disadvantages : You can't buy one in the corner store.

4) Buy a GSM development platform.
  Advantages : You get processor time to add your own functionality.
  Disadvantages : The development system is very expensive. There
  is an extremely steep learning curve. You are on your own with FTA.

5) Buy a GSM engine and connect it to your PIC.
  Advantages : You could save a few bucks per unit if you buy
  in bulk.
  Disadvantages : You have to get FTA (US$100 000 per design).
  You also have to buy a pile of them at a time to get any
  discount. You have to go through a steep learning curve to
  get your PCB design to work OK, and to pass CE.

We can help you with options 2,3, and 5 (>100k quantity).

For quantities 1-1000 option 2) is easier and cheaper to start off.
For quantities 1000-50000 option 3) may be better.
For quantities >50000, option 5 is best.

If you want to have a look at the modem, go to
http://www.wasp.co.za/~tjaart/gcomspecs.html

If you want more info on the ready-made product in Europe, you
could also have a look on our swedish partner's web page at
http://www.cellpt.com/

--
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|--------------------------------------------------|
|                WASP International                |
|R&D Engineer : GSM peripheral services development|
|--------------------------------------------------|
|SMS tjaartspam_OUTspamsms.wasp.co.za  (160 chars max)|
|     http://www.wasp.co.za/~tjaart/index.html     |
|Voice: +27-(0)11-622-8686  Fax: +27-(0)11-622-8973|
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|--------------------------------------------------|

'PIC & SMS GSM'
1998\11\04@063243 by Dr. Imre Bartfai

flavicon
face
On Wed, 4 Nov 1998, Dennis Plunkett wrote:

> At 10:51 4/11/98 +1100, you wrote:
> >Have been playing with this recently, primarily sending over temperature
> >alarms to GSM phones via SMS messaging.  This can be implemented at the most
> >basic level with a DS1820, PIC, 232 driver and a modem.  I've included LCD
> >for entry of nos. to send message to and temperature limits.
> >
> >Have a search for +SMS +"TAP protocol".
> >
> >Also, many pagers use this same protocol.
> >
> >Any other info required, get me off list RemoveMEtimKILLspamspam@spam@modra.com.au
> >
> >
> >Tim Modra
> >
> >{Original Message removed}


'PIC & DMX Lighting control ??'
1999\01\11@120448 by Glenville T. Sawyer
flavicon
face
Hi there,
               is anyone currently working on / with PIC systems to receive
/ send DMX data
for theatre etc etc lighting control ??

I would like to swap notes / ideas  and "PIC" your brains on this.

Trying to start from scratch, need some info on such areas as.....

Decoding the incoming packets, Zero-crossing detection (for direct
Opto-Triac control)
and other questions.


I look forward to your replies.


   Glenville T. Sawyer

1999\01\11@134817 by Roy Turner

flavicon
face
Take a look at the:

   http://www.qsl.net/n5tle/

This link describes a DMX512 dimmer reciever. The output is a set of
analog voltages proportional to the recieved value (such as would be
input to a dimmer pack). This project seems to solve the first part of
your request.

Next, try:

   http://www.mindspring.com/~jlittle/picstuff.html

This describes a MIDI controlled lamp dimmer. From what is presented on
the page, much of this project is untested. However, it would be a
starting point for building a PIC based dimmer.

It would seem that by merging the two projects you could build a DMX
dimmer.

This is something I've wanted to do, but have never been able to find
the time for. If you do something, I'd be interested in hearing about
it.

Good Luck,

Roy

--
Roy Turner                      Email: rturnerspamBeGonespam.....fa.disney.com
Walt Disney Feature Animation   Phone: (818) 526-3334
500 S. Buena Vista St.
Burbank, CA 91521-8950

1999\01\11@163533 by gregnash

flavicon
face
part 0 1234 bytes content-type:text/x-vcard; charset=us-ascii; (decoded 7bit)

Roy Turner wrote:

> Take a look at the:

>     http://www.mindspring.com/~jlittle/picstuff.html
>
> This describes a MIDI controlled lamp dimmer. From what is presented on
> the page, much of this project is untested. However, it would be a
> starting point for building a PIC based dimmer.

There are various kits / magazine projects around for controlling lights
without DMX, including "music color" style dimmers.

keep us all posted...
--
      ______
,----/      \----,  Greg Nash  KILLspamgnashspam.....namoicotton.com.au
 \   |      |   /   Namoi Cotton, PO Box 58, Wee Waa 2388
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1999\01\12@163503 by Harold Hallikainen

picon face
On Tue, 12 Jan 1999 03:34:05 +1030 "Glenville T. Sawyer"
<RemoveMEvk5zcfRemoveMEspamEraseMEGSAWYER.MTX.NET> writes:
>Hi there,
>                is anyone currently working on / with PIC systems to
>receive / send DMX data
>for theatre etc etc lighting control ??

       YES!

>
>I would like to swap notes / ideas  and "PIC" your brains on this.

       I can swap IDEAS, but not code, since I wrote it for my client...
To see descriptions of some PIC based DMX products, see the following
products at http://www.dovesystems.com  : StarPort, TechMaster, Shoebox
dimmer, DMX decoder

>
>Trying to start from scratch, need some info on such areas as.....
>
> Decoding the incoming packets,

       With a 16c74a, I use the UART break detect to detect a start of
packet.  I then use a state machine to figure out where I am in the
packet.  The channels I'm interested in are stored to internal RAM (for
devices that don't need all 512 channels) or a Dallas RamPort external
RAM when we DO need all 512 channels.


Zero-crossing detection (for direct
>Opto-Triac control) and other questions.

       I detected zero-crossing by connecting the INT pin to one side of
the power transformer secondary (with center tap grounded) through a 10K
resistor.  The INT is set to generate an interrupt on a negative
transition, generating an interrupt a little before zero crossing.  I
then use a timer to figure out where the positive zero crossing is.  I
think in my next design I'll add a diode between the FW center tap
rectifier output and the filter capacitor.  A pull-down resistor will
result in full-wave rectified but unfiltered DC at the anode of the added
diode.  I can then add the 10K to the INT pin.  This will result in a
negative edge just prior to BOTH the negative and positive zero-crossing.
This will make it easier to get a low DC component in the dimmer output,
since we won't have to use a timer to predict where the positive zero
crossing is.

>




Harold


Harold Hallikainen
KILLspamharoldspamspamBeGonehallikainen.com
Hallikainen & Friends, Inc.
See the FCC Rules at http://hallikainen.com/FccRules and comments filed
in LPFM proceeding at http://hallikainen.com/lpfm

___________________________________________________________________
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1999\01\12@212751 by tsk3000

picon face
Changing the topic a bit here...

Has anyone here tried to transmit DMX-512 wirelessly via IR or RF or
the like?  I am curious if this is possible... DMX-512 data is
transmitted so fast that it would seem difficult or impossible to
transmit it with one of these methods...  Has anyone attempted
this?  Has it already been done?  Just wondering...

Cheers,
--
~Keith
tsk3000spamspamProdigy.Net
ICQ UIN 15590177
http://pages.prodigy.net/tsk3000/

'PIC & DMX Lighting control wireless'
1999\01\12@235546 by gregnash

flavicon
face
part 0 1091 bytes content-type:text/x-vcard; charset=us-ascii; (decoded 7bit)

In short, IR will be much easier.

Keith Burzinski wrote:

>
> Has anyone here tried to transmit DMX-512 wirelessly via IR or RF or
> the like?  I am curious if this is possible... DMX-512 data is
> transmitted so fast that it would seem difficult or impossible to
> transmit it with one of these methods...



--
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   \/|\    /|\/     home phone 02 6793 5276  fax 02 6793 5319
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1999\01\13@000554 by gregnash

flavicon
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part 0 1334 bytes content-type:text/x-vcard; charset=us-ascii; (decoded 7bit)

Rather than running logical DMX over a different physical link, you could
use a DMX-like protocol of your own design at a lower speed.  You would have
to be happy with not transmitting every real DMX packet, but to avoid
information loss, you could buffer the entire data set.  ie receive real DMX
into memory at high speed and keep it up to date, transfer to another buffer
by slower wireless means, then transmit from that buffer at full speed with
high refresh.

You would see some delay creep into the control, depending how much slower
the wireless part was.



--
      ______
,----/      \----,  Greg Nash  @spam@gnashSTOPspamspam@spam@namoicotton.com.au
 \   |      |   /   Namoi Cotton, PO Box 58, Wee Waa 2388
  \  \ o  o /  /    work phone 02 6790 3011  fax 02 6790 3087
   \/|\    /|\/     home phone 02 6793 5276  fax 02 6793 5319
     | \  / |       mobile 0417 253742
     |  \ \_|       Private GregNashspamBeGonespamspamBeGonepastornet.net.au
     |  |\_/|
     oooooooo       http://www.geocities.com/Nashville/Opry/8450/


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'PIC & DMX Lighting control ??'
1999\01\13@063505 by paulb

flavicon
face
Harold Hallikainen wrote about zero crossing:

> I think in my next design I'll add a diode between the FW center tap
> rectifier output and the filter capacitor.  A pull-down resistor will
> result in full-wave rectified but unfiltered DC at the anode of the
> added diode.  I can then add the 10K to the INT pin.

 Fine, but don't add a diode between the bridge output and filter
capacitor, add *two* from the ends of the power transformer to your
junction of pulldown and current limit resistor.

 This way you are not reducing the efficiency of the power supply.  And
you can use the same two diodes for a bridge rectifier situation.  Not
that you couldn't have used the series diode here too ...
--
 Cheers,
       Paul B.


'PIC & LINUX'
1999\02\08@012438 by Troy P.
picon face
Hi all,
   I have been hearing more and more about LINUX. Does anyone know if
there is any software out there (that runs on LINUX) for programming PIC
devices using the Microchip PICSTART PLUS programmer.
Thanks
spamBeGonetpowspamflash.net

1999\02\08@211012 by Byron A Jeff

face picon face
>
> Hi all,
>     I have been hearing more and more about LINUX. Does anyone know if
> there is any software out there (that runs on LINUX) for programming PIC
> devices using the Microchip PICSTART PLUS programmer.

Not yet. There seems to be an effort to decode and implement such software.
Take a look at the gnupic mailing list archive here:

http://www.scruz.net/~cichlid/gnupic-archive/threads.html

Other tools are available from the gnupic webpage:

http://reality.sgi.com/jamesb/gnupic/

including the gpasm assembler and gpsim simulator. Another useful tool is
the PicProg2.2 parallel port programmer software. Found here:

http://www.tatoosh.com/nexus/picpgmr.shtml

it drives a large number of parallel port PIC programmers. One of my students
and I pieced one together. Works like a champ.

Hope these resources help.

BAJ


'PIC & 8870'
1999\03\09@030809 by Javier
flavicon
face
Hi
I4m interfacing a PIC with a 8870, but with some problems!!
If I don4t connect the PIC with the 8870, the 8870 decodes everything, even
though
I send the tones fast. But when I interface both in order the PIC to save
every recieved tone, the 8870 just decodes some of the tones.What couldbe
the problem ??? Should I put a Buffer between them??
Thanks in advance
Javier

1999\03\09@073142 by Dr. Imre Bartfai

flavicon
face
Hi,

I think the schematic should be shown to justify the problem. I have also
interfaced the 8870 with PIC and it works fine. It's some time ago. I
recall I did it IT-driven and a particular pin of 8870 was tied to RB0/INT
to signal here is a fresh digit. Data lines are connected to RB4..RB7.
I do not hope it helps but can give some hope...
Imre


On Tue, 9 Mar 1999, Javier wrote:

{Quote hidden}

1999\03\09@083841 by PDRUNEN

picon face
i think the PIC should do it without a buffer, I also remember Bob Blicks
design but he used a different chip.  For valid decoding, the 8870 need a
minimum 40mS tone on and 40mS tone off.

Paul

1999\03\09@085304 by John Hansen

picon face
At 05:01 AM 3/9/99 -0300, you wrote:
>Hi
>I4m interfacing a PIC with a 8870, but with some problems!!
>If I don4t connect the PIC with the 8870, the 8870 decodes everything, even
>though
>I send the tones fast. But when I interface both in order the PIC to save
>every recieved tone, the 8870 just decodes some of the tones.What couldbe
>the problem ??? Should I put a Buffer between them??
>Thanks in advance
>Javier

It may be a firmware problem.  The 8870 does not have a latch, so when a new
tone comes in it will displace the last one, sometimes before the last one is
read.  There is a line coming out of the 8870 (I've forgotten the name of it)
that will tell you when a new tone has been received.  You can run this into
the PIC interrupt line and do an interrupt service routine to gather the
tones.  If this is inconvenient, you can go to a 8880 chip, which includes a
latch and a register that can be read.

John Hansen

1999\03\09@122442 by Mike Keitz

picon face
On Tue, 9 Mar 1999 08:53:15 -0500 John Hansen <spam_OUThansenSTOPspamspamFREDONIA.EDU>
writes:

>It may be a firmware problem.  The 8870 does not have a latch, so when
>a new
>tone comes in it will displace the last one, sometimes before the last
>one is
>read.  There is a line coming out of the 8870 (I've forgotten the name
>of it)
>that will tell you when a new tone has been received.

I've only used the very old type of 8870.  It has an output latch that
will remember the last tone received until another one comes in.  The
output that indicates a tone is present is only active, well, while a
tone is present.  At the leading edge of the tone present output, the
4-bit output will represent the new tone.

In order to tell when "new" tones are coming in, your software has to
wait for the tone present signal to go inactive, indicating the first
tone has ended, then wait for it to go active again, indicating a new
tone has been received.  It has to be polled at least every 40 ms, and
faster wouldn't hurt.  My repeater controller polls about every 60 ms,
and some autodialers can outrun it, causing digits to be missed.  Since
the tone input is used infrequently and only by a few people, it didn't
seem to be much of a problem.


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1999\03\09@225015 by Steve Ridley

flavicon
face
I am also using an 8870 interfaced to a PIC. I am using the Holtek CM8870 it
has a pin called StD which I have connected to RA4 to produce an interrupt
when a digit is decoded. I then read the digit within 40 ms by raising the
TOE pin on the 8870 and reading the data on RB4 - 7 which I have connected
to 8870 pins Q1 - 4.

Now while we are on this subject. Has anybody had much success reading DTMF
codes while there is voice on the analog input. I have a telephone line
application that delivers an announcement and waits for DTMF codes. I would
like it to be able to receive DTMF codes while the announcement is being
delivered. To achieve this I connected the raw announcement signal to IN- on
the 8870 to cancel the voice signal being received on IN+. The CM8870 has a
differential analog input IN+ and IN-. This works fairly well but it is not
as reliable as when their is no voice on the line. That is, it misses some
digits. Anyone had any success with this type of thing.

Steve Ridley
Blue Ocean Telecommunications
Sydney,  Australia

{Original Message removed}

1999\03\10@061849 by Stefan Sczekalla-Waldschmidt

flavicon
face
Hi,

> Now while we are on this subject. Has anybody had much success reading DTMF
> codes while there is voice on the analog input. I have a telephone line
> application that delivers an announcement and waits for DTMF codes. I would
> like it to be able to receive DTMF codes while the announcement is being
> delivered. To achieve this I connected the raw announcement signal to IN- on
> the 8870 to cancel the voice signal being received on IN+. The CM8870 has a
> differential analog input IN+ and IN-. This works fairly well but it is not
> as reliable as when their is no voice on the line. That is, it misses some
> digits. Anyone had any success with this type of thing.

I would think some filter will help. You may use a filter which just
let the frequencies pass where the DTMF-Tones are expected.

Kind regards,

       Stefan

1999\03\10@125947 by John Payson

flavicon
face
|Now while we are on this subject. Has anybody had much success reading DTMF
|codes while there is voice on the analog input. I have a telephone line
|application that delivers an announcement and waits for DTMF codes. I would
|like it to be able to receive DTMF codes while the announcement is being
|delivered. To achieve this I connected the raw announcement signal to IN- on
|the 8870 to cancel the voice signal being received on IN+. The CM8870 has a
|differential analog input IN+ and IN-. This works fairly well but it is not
|as reliable as when their is no voice on the line. That is, it misses some
|digits. Anyone had any success with this type of thing.

That's a bit of a tricky issue, since the signal you put onto the
phone line will get attenuated by an amount which may vary somewhat
with the distance to the telco office; you need to subtract out just
the right amount of signal to make things work optimally.  You may
have an easier time if, at least to start with, you feed your audio
signal and the phone line signal into a differential amplifier, with
adjustable gain on your audio signal, and try to "null" it as well as
possible.  That should then give you a pretty good idea of how to set
up the gain when using the 8870's internal diff. amp.

Note also that it's a good idea to mute outgoing audio when you see
something DTMF'ish.  Not only will this allow you to better detect any
digits after the first one, but if you are expecting a long-ish DTMF
digit you can check to make sure muting the audio doesn't cause the DTMF
to disappear (some people's voices can contain just the right frequencies
to fake out DTMF decoders--a phenomenon called "talk-off"; muting the
audio and checking that the DTMF is still present is a good way to mini-
mize that).

Another suggestion I'd add to the last one: the 8870 uses a cap to set
the required present/absent time for a DTMF signal [it "debounces" the
signal, basically].  I'd suggest that you might want to shrink that cap
and do the debouncing in software.  This would allow you to mute the
outgoing audio more quickly.


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1999\03\10@170843 by paulb

flavicon
face
Steve Ridley wrote:

> I would like it to be able to receive DTMF codes while the
> announcement is being delivered.  To achieve this I connected the raw
> announcement signal to IN- on the 8870 to cancel the voice signal
> being received on IN+. The CM8870 has a differential analog input IN+
> and IN-.  This works fairly well but it is not as reliable as when
> there is no voice on the line.  That is, it misses some digits.

 You're describing a hybrid, but are you implementing it properly?

 Basically, it looks like:

Announce o--+---------------------------+
(Audio      |                           |
 source)    >    R                      >    R
            > ~680 ohm                  > ~680 ohm
            |                           |
         +--+-----------+  +------------+--------o
         |  |         __|__|__            Line via isolating
 Line Cl =  >  Rl     \ -  + /              transformer
 dummy   |  > ~680 ohm \    /  op-amp   +--------o
         |  |           \  /   or 8870  |
         M  M            \/             M
         Gnd                             Gnd

 Where Rl and Cl try to match the line.

 There's no way to filter DTMF frequencies out of voice, that's what
the (8870) chip is designed to do already, for better or worse.  A
properly designed hybrid is your best approach.
--
 Cheers,
       Paul B.


'PIC & RS485'
1999\05\28@084716 by John Esposito
flavicon
face
Hello all:

For the next phase of my PIC project (home security), I want to have remote
keypads communicating (only) with the master control unit.  I originally
wanted to use RS232, but was under the impression that RS232 is difficult
to deal with when using long runs (i.e. through a house) and multiple
interface nodes.  For future expandability of the "network", I am leaning
toward RS485, using a Maxim interface chip.  However, I will not run it as
a multi-drop configuration, but as a star-type configuration, with the
keypads running (throughout the house) directly to the master.

My question is:  is my impression of RS232 unfounded?  If so, why?  Has
anyone used RS485 in the way I want to use it?  If so, did you use a
terminating resistor as each node to minimize reflections?  Any other
information you could provide would be very helpful


Regards,

--John

1999\05\28@121314 by Carlos L. M.

flavicon
face
PICLIST@MITVMA.MIT.EDU wrote:

> Hello all:
>
> For the next phase of my PIC project (home security), I want to have remote
> keypads communicating (only) with the master control unit.  I originally
> wanted to use RS232, but was under the impression that RS232 is difficult
> to deal with when using long runs (i.e. through a house) and multiple
> interface nodes.  For future expandability of the "network", I am leaning
> toward RS485, using a Maxim interface chip.  However, I will not run it as
> a multi-drop configuration, but as a star-type configuration, with the
> keypads running (throughout the house) directly to the master.
>
> My question is:  is my impression of RS232 unfounded?  If so, why?  Has
> anyone used RS485 in the way I want to use it?  If so, did you use a
> terminating resistor as each node to minimize reflections?  Any other
> information you could provide would be very helpful
>
> Regards,
>
> --John

You can use the RS232 for long distance but you have to make an amplifier to
use it without problems. I saw one circit sometime, that could use the RS232 in
a ddistance of 100m from the computer. Maybe, if you are intereted in this
circuit, I can search it and send you.

Carlos L.M.

1999\05\28@123906 by Darren Logan

picon face
Hi,

       I've not actually used RS485 in a star connection although I
       use it all the time as multi-drop.

       At baud rates <4800 i find the terminating resistors    unnecessary,
even when there are many nodes with
       the most cheapest of cable (including just wires!!).

       You cant use a terminating resistor for each connection
simply because the total parallel resistance of each would
       be so small that the RS485 lines would effectively be
       short-circuited.
       You could however experiment and put one terminating    resistor at
the master end only but personally, i'd leave 'em
       out altogether. I almost guarantee you wont have any    problems as
long as you keep the baud rate to say 1200.

Regards,
Darren

1999\05\28@132304 by John Esposito

flavicon
face
Carlos:

What about using RS232 in a multi-drop or star configuration?  I though
RS232 was point-to-point.

--John





> My question is:  is my impression of RS232 unfounded?  If so, why?  Has
> anyone used RS485 in the way I want to use it?  If so, did you use a
> terminating resistor as each node to minimize reflections?  Any other
> information you could provide would be very helpful
>
> Regards,
>
> --John

You can use the RS232 for long distance but you have to make an amplifier
to
use it without problems. I saw one circit sometime, that could use the
RS232 in
a ddistance of 100m from the computer. Maybe, if you are intereted in this
circuit, I can search it and send you.

Carlos L.M.

1999\05\28@142935 by Jamil J. Weatherbee

flavicon
face
Recommendation is if you just want a star configuration RS232 that will
work reliably at long distance use RS422 (5-Wires, Full Duplex)
This is same interface used on Macintosh serial ports.  RS485 is an
improvement on RS422 that allows multimaster, which you don't need in a
star configuration.

For RS422 you can basically just use CAT5 Cable, and terminate both ends
with 100ohm resistors, see the national semiconductor application notes.


On Fri, 28 May 1999, John Esposito wrote:

{Quote hidden}

1999\05\28@143316 by William K. Borsum

flavicon
face
At 12:49 PM 5/28/99 -0400, you wrote:
>Carlos:
>
>What about using RS232 in a multi-drop or star configuration?  I though
>RS232 was point-to-point.
>

It usually is.  For multi-drop, try RS485.  There is an IEEE standard (1118
I think) that defines an address and packet system for talking to multiple
black boxes.  Basically, the first byte is 9-bits and contains the address,
and the subsequent 8-bit bytes contain the data.  As soon as a pause in the
data stream occurs, or the packet is complete, the receivers must switch
back to watching for the 9-bit address again.  Supposedly the UARTS in the
newer PICs support this.  We are looking at doing a system with 100+ data
loggers spread down an 18,000 foot long structure with a repeater every few
thousand feet.  The wire will end up costing more than the electronics :_p.

If anyone has implemented this protocol in a 16C7xx or similar, I would
sincerely appreciate a copy of the code or a point to it.

Kelly

****************************************************************************
********
All legitimate attachments to this email will be clearly identified in the
text.
William K. Borsum, P.E.
OEM Dataloggers and Instrumentation Systems
<RemoveMEborsumspamspamdascor.com> & <http://www.dascor.com>

1999\05\28@150028 by Vic Lopez

flavicon
face
Carlos, I'd be interested in that circuit. Thanks. Vic Lopez
-----Original Message-----
From: Carlos L. M. <TakeThisOuTclmspamspamRemoveMEPLANET.COM.BR>
To: KILLspamPICLISTspamspamspam_OUTMITVMA.MIT.EDU <PICLISTRemoveMEspamMITVMA.MIT.EDU>
Date: Friday, May 28, 1999 9:09 AM
Subject: Re: PIC & RS485


>EraseMEPICLISTSTOPspamspamRemoveMEMITVMA.MIT.EDU wrote:
>
>> Hello all:
>>
>> For the next phase of my PIC project (home security), I want to have
remote
>> keypads communicating (only) with the master control unit.  I originally
>> wanted to use RS232, but was under the impression that RS232 is difficult
>> to deal with when using long runs (i.e. through a house) and multiple
>> interface nodes.  For future expandability of the "network", I am leaning
>> toward RS485, using a Maxim interface chip.  However, I will not run it
as
{Quote hidden}

to
>use it without problems. I saw one circit sometime, that could use the
RS232 in
>a ddistance of 100m from the computer. Maybe, if you are intereted in this
>circuit, I can search it and send you.
>
>Carlos L.M.
>
>

1999\05\28@153657 by Bob Drzyzgula

flavicon
face
On Fri, May 28, 1999 at 08:39:44AM -0400, John Esposito wrote:
...
> My question is:  is my impression of RS232 unfounded?  If so, why?  Has
> anyone used RS485 in the way I want to use it?  If so, did you use a
> terminating resistor as each node to minimize reflections?  Any other
> information you could provide would be very helpful

FWIW, the latest issue of Circuit Cellar (June, 1999)
contains an article by Jan Axelson entitled "Designing
RS-485 Circuits". She does a pretty good job of explaining
the issues surrounding signalling & slew rate, termination,
and cable length, and how they affect attenuation,
reflections, etc. Well worth the cover price.

--Bob

--
============================================================
Bob Drzyzgula                             It's not a problem
spam_OUTbobRemoveMEspamEraseMEdrzyzgula.org                until something bad happens
============================================================

1999\05\28@155636 by John Mitchell

flavicon
face
On Fri, 28 May 1999, Bob Drzyzgula wrote:

> FWIW, the latest issue of Circuit Cellar (June, 1999)
> contains an article by Jan Axelson entitled "Designing
> RS-485 Circuits". She does a pretty good job of explaining
> the issues surrounding signalling & slew rate, termination,
> and cable length, and how they affect attenuation,
> reflections, etc. Well worth the cover price.

Her articles were the sole reason to pick up The MicroComputer Journal --
always interesting, relvant, and useful.

Check out her site: Lakeview Research -- http://www.lvr.com/


- j

1999\05\28@191110 by paulb

flavicon
face
John Mitchell wrote:

>> FWIW, the latest issue of Circuit Cellar (June, 1999) contains an
>> article by Jan Axelson entitled "Designing RS-485 Circuits".

> Her articles were the sole reason to pick up The MicroComputer Journal
 Never was particularly fond of PICs though...  Strictly 8051
--
 Cheers,
       Paul B.

1999\05\29@030257 by Russell McMahon

picon face
I wouldn't recommend RS232 for long runs if it can be avoided and it
is definitely outside the formal specification

BUT

at 300 baud it will run with essentially 100% reliability over very
large distances on wet string (well, maybe the water needs to be
salty :-)).
Think about it - you have a nominal +/- volt swing - say +/- 5 in
practice. At 300 baud you have 3ms per bit. With 1 mile/1600 metres
of wire you probably have say 500 ohms max resistance and 100 nF
capacitance. Time constant of this is about 50 microsecond or about
1/60th of a bit time. Faster baud rates will give narrower margins
but I'd expect reliable operation around a house at baud rates
significantly above 300 baud. That said, it's outside the spec - look
at the results on a 'scope and decide for yourself.

Summary: For around a house and SLOW data rates it will work. If you
can use differential drivers (RS422) then you'll get better
reliability.

(Being picky AFAIR RS422 is mono-drop and RS485 has the spec
extensions to cover multi-drop)


regards


       Russell McMahon

From: John Esposito <    >
>For the next phase of my PIC project (home security), I want to have
remote
>keypads communicating (only) with the master control unit.  I
originally
>wanted to use RS232, but was under the impression that RS232 is
difficult
>to deal with when using long runs (i.e. through a house) and
multiple
>interface nodes.  For future expandability of the "network", I am
leaning
>toward RS485, using a Maxim interface chip.  However, I will not run
it as
>a multi-drop configuration, but as a star-type configuration, with
the
>keypads running (throughout the house) directly to the master.
>
>My question is:  is my impression of RS232 unfounded?  If so, why?
Has
>anyone used RS485 in the way I want to use it?  If so, did you use a
>terminating resistor as each node to minimize reflections?  Any
other
>information you could provide would be very helpful

1999\05\29@061218 by paulb

flavicon
face
Russell McMahon wrote:

> BUT
> at 300 baud it will run with essentially 100% reliability over very
> large distances on wet string (well, maybe the water needs to be
> salty :-)).

 Sounds fine to me.  RS-232 *is* after all differential - it operates
on the difference between the TXD and GND wires.  If you use *real*
RS/ EIA-232 with *real* +/- 10V drive, it should work quite a long
distance at quite high baudrates.

 Accordingly, I see just three problems with it.

 1} The single-ended protocol is quite susceptible to bias from ground
returns, so it may well need an isolated receiver (just like that
recommended for RS-422/ 485!).

 2} You must *use* RS-232, not "imaginary RS-232" with 5V CMOS logic
levels, which is really "asking" for threshold problems.

 3} Many/ most receivers include termination because - that is
specified in the standard.  Paralleling these for "multi-drop" may well
result in out-of-spec termination, in which case again it would be
deceitful to say "RS-232 is not good enough".
--
 Cheers,
       Paul B.

1999\05\29@073301 by ranguelo

flavicon
face
Hi !

John Esposito wrote:
>
>
> For the next phase of my PIC project (home security), I want to have remote
> keypads communicating (only) with the master control unit.  I originally
> wanted to use RS232, but was under the impression that RS232 is difficult
> to deal with when using long runs (i.e. through a house) and multiple
> interface nodes.

For both RS485 and RS232 you can increase the maximum distance by
decreasing
the speed (boudt rate). I expect for interfacing a keyboard or card
reader
you wouldn't need more then 1200 bps.

For future expandability of the "network", I am leaning
> toward RS485, using a Maxim interface chip.  However, I will not run it as
> a multi-drop configuration, but as a star-type configuration, with the
> keypads running (throughout the house) directly to the master.

If you want to do the termination right, you can use at your control
unit
one transmitter and receiver driver for each line and make the
connection of
all signals on the TTL side of the drivers. So physically every line
will have
a driver circuit (and a terminator for RS485) on each end.

It costs more, but imho it makes sense for a security system. If someone
attacks one of the lines and blows the driver circuit away with a high
voltage applaied to the cable you can manage it to keep the other
keypads
working.

>
> My question is:  is my impression of RS232 unfounded?  If so, why?  Has
> anyone used RS485 in the way I want to use it?
>

Haven't tried it myself. There are some ideas :

- Terminate only one side of the line (at the transmitter). Then a
reflected
wave travels back from the end to the transmitter and is absorbed by the
terminator and doesn't affects the next transmission.

- You can terminate only the AC part of the signal by putting a C in
series
with the terminator. So the voltage wouldn't drop if you connect
parallel
more terminated cables.

- If not terminating at all you can use diodes to clamp the positive and
negative overshoot of the reflected wave. Such diodes are build in most
ICs.


If cost is a problem you can try it first by reducing the speed and by
using
a check sum in the transmission protocol to make it immune to errors.
(That's
the way the one-wire bus by Dallas works: no termination, slow speed and
a CRC check.)


Just my 2 cents ...
St.


'PIC & RS485'
1999\06\02@023620 by Zdenek Bohm
flavicon
face
Carlos, I'd be interested in that circuit. Thanks. Zdenek - TakeThisOuTbohmRemoveMEspam@spam@gacc.cz

'PIC & Mother Board'
1999\06\14@204051 by Jočo Batista

flavicon
face
I am beginning to sketch a project of interface of PC 486 or Pentium with PIC for access  solid state disk ( SANDISK ) and video card's.  
Would like to know somebody knows a site where I can get an schematic, or same if somebody possesses one, of any motherboard of PC to try to simulate the PC with PIC.  
 
Project: To create a personal computer portable with PIC for Virtual Reality.  
 
I believe that if it was possible to modify a PDA, would also give to do the experience, I am right?  
 
Respectfully,

Joao Batista
EraseMEjq96RemoveMEspamclaret.com.br

1999\06\15@063146 by Harrison Cooper

flavicon
face
Being involved in VR myself, I honestly don't think you have enough
horsepower in a PIC to do this, let alone attempt to emulate a PC
motherboard.  Its one thing to dump graphics data from a storage device to a
display, but to manipulate it in real time is another story.  They have
credit card 486 computers available now (be it they are not cheap), and if
you really are serious about attempting something like this, use something
of this nature.  Our PC based real time simulation boxes used dual and quad
Xenon servers, and this does not include the high end video cards.



{Original Message removed}


'PIC & Maxim485'
1999\07\08@162854 by John Esposito
flavicon
face
Question:

I am trying to implement RS485 using a Maxim 3082 (half duplex) and a PIC.  I
want to conserve PIC I/O pins (don't we all??); is this layout acceptable?

PIC RB0 - controls TX/RX mode; tied directly to MAX ~RE (rx enable not) and MAX
DE (tx driver enable)
PIC RB1 - bi-directional input; tied directly to MAX RO (rx output) and MAX DI
(tx input)

When RB0 is low (receiving), RO splits its output between DI (which is in don't
care state) and RB1
When RB0 is high (trans), RB1 splits its output between DI and RO (which is in
High-Z)

Is this acceptable?  Is any other hardware (resistors, etc) necessary?  Assuming
I allow for propagation delays, all should be well, right??

Any comments are greatly appreciated.


Regards,

--John

1999\07\08@164041 by Adam Davis

flavicon
face
I've done it that way, and it works very well, although I've seen people tie the
~re to the pic, and the de to the same pin, but through a resister.  I'm not
sure what this would accomplish...

-Adam

John Esposito wrote:
{Quote hidden}

ng
> I allow for propagation delays, all should be well, right??
>
> Any comments are greatly appreciated.
>
> Regards,
>
> --John

1999\07\09@004657 by Jamil J. Weatherbee

flavicon
face
what you are trying to do could get a bit messy.

On Thu, 8 Jul 1999, John Esposito wrote:

{Quote hidden}

ng
> I allow for propagation delays, all should be well, right??
>
> Any comments are greatly appreciated.
>
>
> Regards,
>
> --John
>

1999\07\09@004711 by Jamil J. Weatherbee

flavicon
face
If you are real clever and want to add a small cap and a couple of
transistors I bet you could do the entire interface with 1 PIC pin.
Given that the slew rate on the pic TX pin is known.




On Thu, 8 Jul 1999, John Esposito wrote:

{Quote hidden}

ng
> I allow for propagation delays, all should be well, right??
>
> Any comments are greatly appreciated.
>
>
> Regards,
>
> --John
>

1999\07\09@012620 by Dennis Plunkett

flavicon
face
At 21:01 8/07/99 -0700, you wrote:
>what you are trying to do could get a bit messy.
>
>On Thu, 8 Jul 1999, John Esposito wrote:
>
>> Question:
>>
>> I am trying to implement RS485 using a Maxim 3082 (half duplex) and a
PIC.  I
>> want to conserve PIC I/O pins (don't we all??); is this layout acceptable?
>>
>> PIC RB0 - controls TX/RX mode; tied directly to MAX ~RE (rx enable not)
and MAX
>> DE (tx driver enable)
>> PIC RB1 - bi-directional input; tied directly to MAX RO (rx output) and
MAX DI
>> (tx input)
>>
>> When RB0 is low (receiving), RO splits its output between DI (which is
in don't
>> care state) and RB1
>> When RB0 is high (trans), RB1 splits its output between DI and RO (which
is in
>> High-Z)
>>
>> Is this acceptable?  Is any other hardware (resistors, etc) necessary?
Assuming
{Quote hidden}

Yes this could be a bit messey in that the chip you want to use is full
duplex. There will be some small amounts of backdrivig when changing from
TX to RX and Vice versa. But most of this will be on the RS485 line, thus
you may get some small glitches when chanigng state, unless you force an
idle state at both ends before attempting to start a transmit cycle.
To avoild contention at the PIC on the data line, when changing from
Transmit to receive mode, set it to an input, then change the enable line
to the RS485 driver, also you will need to pull this data line (On the PIC
side) to the idle state so that during this process you will not cause crap
to go out (Resistor required).
When going from RX to TX ,set the data line to an output first (An place in
the idle state) then change the driver enable. The small contention time
can be lived with, if you want a resistor say 1k can be in series to reduce
the current flow at this point in time.
Repeat the same process on the other end. Dont forget to terminate at
100-120R on the 485 side. You may also need to bias the lines so that the
idle state is guarenteed at all times when nothing is connected etc.

Dennis

1999\07\09@083324 by paulb

flavicon
face
Dennis Plunkett wrote:

> When going from RX to TX ,set the data line to an output first (An
> place in the idle state) then change the driver enable. The small
> contention time can be lived with,

 Sorry, but I don't see the point in this.  You avoided contention
in the other direction by disabling the PIC first, using a pull-up to
hold it in idle *then* enabling the receiver driver.

 Why will this same resistor not work if you *disable* the receiver
driver first, *then* enable the PIC output (pre-set to the idle state)?
--
 Cheers,
       Paul B.

1999\07\09@100148 by John Esposito

flavicon
face
Dennis:

The MAX3082 is half duplex - does this change what you described?



Yes this could be a bit messey in that the chip you want to use is full
duplex. There will be some small amounts of backdrivig when changing from
TX to RX and Vice versa. But most of this will be on the RS485 line, thus
you may get some small glitches when chanigng state, unless you force an
idle state at both ends before attempting to start a transmit cycle.
To avoild contention at the PIC on the data line, when changing from
Transmit to receive mode, set it to an input, then change the enable line
to the RS485 driver, also you will need to pull this data line (On the PIC
side) to the idle state so that during this process you will not cause crap
to go out (Resistor required).
When going from RX to TX ,set the data line to an output first (An place in
the idle state) then change the driver enable. The small contention time
can be lived with, if you want a resistor say 1k can be in series to reduce
the current flow at this point in time.
Repeat the same process on the other end. Dont forget to terminate at
100-120R on the 485 side. You may also need to bias the lines so that the
idle state is guarenteed at all times when nothing is connected etc.

Dennis

1999\07\11@175245 by Dennis Plunkett

flavicon
face
At 09:52 9/07/99 -0400, you wrote:
{Quote hidden}

I will have to look at teh MAX data to see if that is so. The MAX may have
internal resistors. Whatever the results, I think that the basic control
remains the same.


Dennis

'PIC & USB'
1999\07\31@032454 by Vlad Smetanko

picon face
A PIC communicated with USB. I did it.
I can do it and more for You.

Are You interested the source that operates a few switches and LEDs by USB?
I have both ends, the PIC and the C++ application  & Win2000 driver.

My Experience in:
-Control, DSP, Medical Systems;
-PIC-MicroContr. UART, SPI, I2C, LPT, USB
-MPLAB 3.99, OrCad 7.0, Visual Basic 6.0 for Windows'98, ...
RESUME:
http://www.geocities.com/SiliconValley/Garage/1943/

Thanking You in advance for answer!
Vlad


---------------------------------------------------
Get free personalized email at http://www.iname.com


'PIC & IDE'
1999\09\27@212216 by Rob Bakker
flavicon
picon face
Hello,
   Anyone tried a PIC to IDE combination?  any pointers/URL's/pitfalls?

Thanks in advance

RoB>)

spamRob.....spamspamwaikato.ac.nz

1999\09\28@094227 by Wesley Moore (Yallara)

flavicon
picon face
Check out my page for some IDE info:

http://www.hotkey.net.au/~moore.w/pic/IDE_to_8255.html

Please note that I didn't write the document, the author is at the top of
the page.

Wesley

On Tue, 28 Sep 1999, Rob Bakker wrote:

> Hello,
>     Anyone tried a PIC to IDE combination?  any pointers/URL's/pitfalls?
>
> Thanks in advance
>
> RoB>)
>
> Robspam_OUTspam@spam@waikato.ac.nz
>

1999\09\28@094642 by eplus1

flavicon
face
The closest I have seen is:
http://www.nomad.ee/micros/ - Info on an 8052 IDE interface. Started off
using a PIC but changed due to PIC limitations. Hardware interface fully
implemented, software interface partially interfaced.

Maybe also:
http://www.blkbox.com/~jdb8042/SmallSys/8bitIDE.html

http://nimitz.mcs.kent.edu/~clisowsk/8bit/ide8bit.html

www.hotkey.net.au/~moore.w/pic/IDE_to_8255.html
For a complete treatment of IDE interfacing to 8-bit CPUs (particularly the
Z80 family), check out issues 56, 63, 64, and 66 of The Computer Journal.
There is a simple IDE interface for the Z80 called GIDE (Generic IDE). It
should be possible to adapt it to other 8-bit processors. There is an
article about it on the TCJ Web Page. Click on 'GIDE'.

If you do it, please document it. <GRIN>

James Newton, webmaster http://get.to/techref
(hint: you can add your own private info to the techref)
.....jamesnewtonspamspam.....geocities.com
1-619-652-0593 phoneÊ



-----Original Message-----
From: pic microcontroller discussion list
[PICLISTKILLspamspamEraseMEMITVMA.MIT.EDU]On Behalf Of Rob Bakker
Sent: Monday, September 27, 1999 6:24 PM
To: EraseMEPICLIST@spam@spam@spam@MITVMA.MIT.EDU
Subject: PIC & IDE


Hello,
   Anyone tried a PIC to IDE combination?  any pointers/URL's/pitfalls?

Thanks in advance

RoB>)

@spam@RobspamspamKILLspamwaikato.ac.nz

'PIC & SRAM CARD INTERFACING'
1999\09\28@103620 by Craig Lee

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How do I diddle the SRAM card contents
from the embedded side of things, and
have the PC see the files as DOS format.

Where does the FAT table go, etc...

I've looked everywhere for a spec, and
can't find any useful information.  I'd
be happy to buy a spec. if I could be
certain that the information I need is
there.  Any leads?

I've interfaced to a 1Mbyte SRAM card with
a 16C73 and some address latches.  What I
wish to do is put the data in the right
format so that existing software packages
can directly read the SRAM card when
inserted into the PCMCIA port.

Thanks,

Craig

1999\09\28@153732 by Mark Willis

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I'd go about it the other way 'round;  Get a card stuck into a PCMCIA
port on a desktop or laptop, format it & stuff files onto it - then
figure out from that card (with those known files on it & your knowledge
of how DOS etc. do file structures), how Dos handles SRAM card file
info.  I'd guess it's treated just like a tiny IDE Hard Drive;  That's
the pattern I've seen from Flash cards, and a number of laptops can boot
from SRAM and/or Flash cards (IBM PC110, etc.)  Linux sources should be
good here, too...

http://www.pcmcia.org/ is a good place to look "For All Things PCMCIA",
of course;  Release 7.0 of the PC Card Standard may or may not have DOS
file structure info there for you.  I have a multitude of laptops here &
some PCMCIA SRAM cards as well, can help if you know what you want to
see from the laptop side of things.

 Mark

Craig Lee wrote:
{Quote hidden}


'PIC & IDE'
1999\10\12@135643 by Les
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I recall seeing something about interfacing a PIC to an IDE drive..

Does anyone have a URL for a site that documents interfacing to IDE?


Leslie Bester
Chief Technical Officer
Gallmark Corporation
500-280 Smith St.
Winnipeg, MB.   R3C 1K2

Contact Specifications:
204-944-1119 (voice office)
204-949-0768 (fax office)
204-933-5164 (pager)
204-229-1082 (cellular)
spamBeGonelesRemoveMEspamEraseMEgallmark.mb.ca (email)
RemoveMEpagerKILLspamspamRemoveMEgallmark.mb.ca (email pager)

-----BEGIN GEEK CODE BLOCK-----  Version: 3.1
dpu(--) s: a- C+++(++++) UL++(++++) P++(+++>)
L+++(++++>) E- w++ O M- V PS+ PE Y-- PGP- t@ 5@
X+(++) R(-) tv- b+(++) DI+++ D+ G e h(*) r y+ z
------END GEEK CODE BLOCK------

1999\10\12@140648 by Stevens, Kurt

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Here are the ones I kept from the list:


http://www.spectsoft.com/mp3tech/
http://www.angelfire.com/pa2/mpx/
www.hotkey.net.au/~moore.w/pic/IDE_to_8255.html
http://spectsoft.dynip.com/mp3tech/index.htm
http://www.nomad.ee/micros/
www.blkbox.com/~jdb8042/SmallSys/8bitIDE.html
http://nimitz.mcs.kent.edu/~clisowsk/8bit/ide8bit.html

Note that some of these are pertaining to ATAPI

       Kurt Stevens

{Quote hidden}

'PIC & PAL'
1999\10\16@175740 by John De Villiers

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Is there any info anywhere on how to get a pic to display stuff on a TV
screen in PAL  format ?

I know of one that you can buy, but i wanna try making one myself.

John

'PIC & iButton'
1999\10\21@132035 by Les

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Hi.
I was looking into the single-wire iButtons, and wanted to hook up aprox 100
"reader-stations" spread out over 50,000 square feet, which all funnel down
to a single PC via serial port. (Or perhaps a couple serial ports if need
be)

What I envision is having several pics, each having the capability to
provide contacts to read 5-10 iButtons..  Each of these pics would reside on
some common bus and eventually stream the data to a PC with a serial port.
Each contact station would append a "station-id" to the 64bit serial number
that the iButton reports...

Has anyone been exposed to a setup like this?


Leslie Bester
Chief Technical Officer
Gallmark Corporation
500-280 Smith St.
Winnipeg, MB.   R3C 1K2

Contact Specifications:
204-944-1119 (voice office)
204-949-0768 (fax office)
204-933-5164 (pager)
204-229-1082 (cellular)
lesSTOPspamspamgallmark.mb.ca (email)
pagerSTOPspamspamKILLspamgallmark.mb.ca (email pager)

-----BEGIN GEEK CODE BLOCK-----  Version: 3.1
dpu(--) s: a- C+++(++++) UL++(++++) P++(+++>)
L+++(++++>) E- w++ O M- V PS+ PE Y-- PGP- t@ 5@
X+(++) R(-) tv- b+(++) DI+++ D+ G e h(*) r y+ z
------END GEEK CODE BLOCK------

'IR coding - decoding with PIC & C software.'
1999\10\24@110924 by Eric Richards

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Hi Henk VK2GWK

Philips has standards, you could get from them , not too sure about any
others

Did you have any brand in mind, or just all of them
++++++++++++++++++++++++++++++++++++++
By the way is there some free C compiler software for the pic around.
++++++++++++++++++++++++++++++++++++++
Signs That You've Had Too Much Of The 90's

1. You try to enter your password on the microwave.
2. You haven't played patience with real cards in years.
3. You have a list of 15 phone numbers to reach your family of 3.
4. You e-mail your work colleague at the desk next to you to ask "Do you
fancy going down the pub?" and they         reply "Yeah, give me five
minutes"
5. You chat several times a day with a stranger from South America, but you
haven't spoken to your next door         neighbour yet this year.
6. You buy a computer and a week later it is out of date.
7. Your reason for not staying in touch with friends is that they do not
have e-mail addresses.
8. You consider Royal Mail painfully slow or call it "snail mail".
9. Your idea of being organised is multiple coloured post-it notes.
10. You hear most of your jokes via Email instead of in person.


>From Eric
There is 30 more, Signs That You've Had Too Much Of The 90's , More next
time.



{Original Message removed}

'PIC & iButton'
1999\10\25@054445 by Dr. Imre Bartfai

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Hi,

please clarify. In fact, the main question is, whether you want that
amount of said iButtons (5-10 pcs) exactly at once, or rather you want
only to set up reader stations. That is, iButton reader stations can be
connected to ONE one-wire bus provided there is no collision, i. e. only
one iButton is connected at one time. With other words: one one-wire bus
can serve a vaste amount of reader stations IF there is only one button.
Further: Dallas provides a sophisticated mechanism called Search ROM which
makes possible to connect more Buttons at a time to a particular bus. And
this only one pin of a PIC!

The allowed length of the bus I do not know off the cut, but this can be
the major factor to calculate the number of PICS, which, on the other
hand, can be connected together to a RS-485 bus.

I hope this helps.

Regards,
Imre


On Thu, 21 Oct 1999, Les wrote:

{Quote hidden}


'AT90S2313, & PIC & Silicon cip Nov 99'
1999\11\06@153149 by Eric Richards
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In the latest Australia "Silicon Chip" November 1999
There is a Project "Car speed alarm" uses a PIC16F84
For more about the magazine see their web site http://www.siliconchip.com.au
or if you have a great project and it should be published Email
silchip.....spamsiliconchip.com.au
(I'm just a reader)
==================== more ================
Also there is a another project "Christmas tree" uses a AT90S2313 this is a
20 pin device
microcontroller  for Manufacture's data sheets application notes
http://www.atmel.com

Sample start up code .http://www.dontronics.com/8515.html

More simple code and an FAQ http://www.avr-forum.com/

If you are a speed reader from this group and a big Email box and would like
to read more
send Email to KILLspamatmel-requestspam_OUTspampic.co.za with the word '   JOIN    ' in the
body of the Email

1999\11\06@162220 by paulb

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Eric Richards wrote:

> In the latest Australia "Silicon Chip" November 1999 There is a
> Project "Car speed alarm" uses a PIC16F84

 Now that's more like it.  Do they publish the source so you can adapt
it/ enhance it etc.?  I'll check this arvo.

> If you are a speed reader from this group and a big Email box and
> would like to read more send Email to spam_OUTatmel-requestspamTakeThisOuTpic.co.za ...

 Ha Ha Ha!  The ATMEL list is unbelievably *TAME* compared to this one.
--
 Cheers,
       Paul B.


'Searching friends for build a PIC & WEB based proj'
1999\12\30@144350 by Leo
picon face
Hi PICer friends,

I have been an idea for project tha can be useful on the WEB.

The idea in extreme sinthesys consist to connect to the PC a piece of
hardware, tipically a PIC on the paralell port that permit the access to a
special page on the WEB server like a key or password.

If someone is interested, please send me an E-MAIL at the following address:

.....cacciavite.....spamRemoveMEbigfoot.com

and using on the subject the words PIC & WEB

Thanks

Saluti a tutti e un augurio di un prospero e felice anno nuovo. BUON ANNO


Leo

1999\12\30@155436 by quozl

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Design idea ... add a connector to the keyboard cable, allow a PIC in a
case to be attached to the cable, the user hits a key combination at a
particular time and the "password" is sent down to the PC.

--
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'PIC & Linux'
2000\03\04@123000 by alexis yahoo
picon face
Does somebody know a software to use the piscstart plus programmer along
with debugger, etc (Something like mplab) but to work under linux ??
Thanx !


__________________________________________________
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Talk to your friends online with Yahoo! Messenger.
http://im.yahoo.com


'[PICLIST] [EE] [Photo] PIC & IDE HD based mass sto'
2000\07\27@183310 by wzab
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Hi All,

Sorry for off-topic message, but the piclist seems to me to be the best
EE forum, where such a strange project could be announced.
I have an idea of small device, which could make life of digital
photocameras users much easier. The SmartMedia cards are rather expensive,
and taking the laptop everywhere is neither safe nor convenient.
So I think that a simple mass storage for digital photocameras would be
useful. It could contain just a microcontroller equipped with serial
interface and able to emulate an IDE interface.

The basic functions should be very simple:

1) Downloading the pictures from the cammera (through RS232) & erasing of
 succesfully downloaded pics
2) Uploading the pictures to the PC (through RS232) & deleting of
 successfully transferred pics

The additional functions could be useful as well:
3) Uploading of selected pictures to the camera
4) Deleting of selected pictures

So the device could be very simple. It could contain only uC (eg 16F877),
IDE HD (I'm going to use an old but good 200MB HD), the numeric LCD display
(to inform about number of selected picture or number of pictures written on
disk or to show the progress of transmission) and probably a few interface
circuits.

The details of protocol may be found eg. in file protocol.htm included in
the freely available "photocd" software (for using dig. cams with Linux).
(Or in http://www.average.org/digicam/ website)

I'm interested in any comments regarding such design and in any pointers
considering the PIC<->IDE HD connectivity.

--
                       TIA
                       Wojciech Zabolotny
                       http://www.ise.pw.edu.pl/~wzab

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2000\07\28@015830 by Tsvetan Usunov

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---snip---
>  I have an idea of small device, which could make life of digital
> photocameras users much easier. The SmartMedia cards are rather expensive,
> and taking the laptop everywhere is neither safe nor convenient.
>  So I think that a simple mass storage for digital photocameras would be
> useful. It could contain just a microcontroller equipped with serial
> interface and able to emulate an IDE interface.


I think there should be some info (or links) about ATAPI interface:

http://www.pjrc.com/tech/mp3/

Regards
Tsvetan
---
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2000\07\28@090519 by wzab

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On Fri, Jul 28, 2000 at 08:47:07AM +0200, Tsvetan Usunov wrote:
> ---snip---
> >  I have an idea of small device, which could make life of digital
> > photocameras users much easier. The SmartMedia cards are rather expensive,
> > and taking the laptop everywhere is neither safe nor convenient.
> >  So I think that a simple mass storage for digital photocameras would be
> > useful. It could contain just a microcontroller equipped with serial
> > interface and able to emulate an IDE interface.
>
>
> I think there should be some info (or links) about ATAPI interface:
>
> http://www.pjrc.com/tech/mp3/
>

After checking the links, I see, that I'll need an uC with at least 4KB
data RAM included, ca. 8KB to 16KB code EEPROM, SCI interface
and ca. 30 I/O lines.
Does anybody could suggest what should be used for this purpose?
I've found the 68HC916Y3 from Motorola, but it does not seem to be very
cheap ;-).
--
                             Wojciech M. Zabolotny
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2000\07\28@104241 by Harold Hallikainen

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       How about using a FDD instead of HD? That would give a substantially
lower cost and infinite storage (assuming your pockets are large enough
for all the floppies)?
       I have another application for FDD on a PIC and will eventually start
writing code if no one else does...

Harold

________________________________________________________________
YOU'RE PAYING TOO MUCH FOR THE INTERNET!
Juno now offers FREE Internet Access!
Try it today - there's no risk!  For your FREE software, visit:
dl.http://www.juno.com/get/tagj.

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'[EE]: [Photo]: PIC & IDE HD based mass storage for'
2000\07\28@111328 by wzab

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On Fri, Jul 28, 2000 at 07:36:39AM -0700, Harold Hallikainen wrote:
>         How about using a FDD instead of HD? That would give a substantially
> lower cost and infinite storage (assuming your pockets are large enough
> for all the floppies)?
>         I have another application for FDD on a PIC and will eventually start
> writing code if no one else does...

I think that the floppies are much less reliable :-(. It is very easy now
to buy the "outdated" HD with capacity < 1GB which should be sufficient
for this purpose.

BTW I'd like to answer on the list questions I've received from different
readers regarding this project (to avoid answering individually all of them):

1) The project is intented to be the free open source project
  (with GPL or "artistic" license)

2) Addition of USB and other interfaces is appreciated, however at the
  moment I'm not interested in it (neither my camera nor my PC has USB).
  However the potential need for USB may influence the choise of proper
  uC. Any suggestions are welcome.

3) The device should be powered from the 12V (car battery?).
  BTW. What are the HD's requirements regarding the stability of +12V
  voltage? (Maybe it will be necessary to use a stabilizer/converter:
  +12V (batt. unstable) - DC/DC pulse converter -> +12V stabilized
   |
   +- DC/DC pulse converter -> +5V stabilized

--
                       Thanks for all the feedback
                          Wojciech M. Zabolotny
       http://www.ise.pw.edu.pl/~wzab  <--> .....wzabRemoveMEspamise.pw.edu.pl

http://www.freedos.org  Free DOS for free people!

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'[EE]: [Photo] PIC & IDE HD based mass storage for '
2000\07\29@044240 by Snail Instruments

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Hi Harold,

this has been discussed several times already. The FDD output is just an
amplified signal from the read heads (and input similar, I guess). You need
either a FD controller or a micro capable of processing 0.5Mb/s bit stream
and holding at least one sector of data (512B). Then comes the easy task -
implementing filesystem.

But you wanted a challenge, so this one will last ;-)

BTW, for removeable media we should perhaps consider the IDE Iomega ZIPdrive.

Josef

>        How about using a FDD instead of HD? That would give a substantially
>lower cost and infinite storage (assuming your pockets are large enough
>for all the floppies)?
>        I have another application for FDD on a PIC and will eventually start
>writing code if no one else does...

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2000\07\29@071358 by Peter L. Peres

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>floppy storage driven by PIC

I am curious as to how one would make a PIC w/o external RAM store the
data for even a single sector of data. The data rate is about 500
kBytes/sec with a normal 31/2 drive (lower than 500). This is based on a
4MHz physical bit write clock. A 16 or 20 MHz PIC can probably drive this
(but not read ?). Evens so, where does one get 512 bytes of data for
storage (medium fast access storage, serial is 'out').

Peter

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2000\07\29@102339 by Harold Hallikainen

picon face
       Thanks for the comments! I've got a product out now using the 18c452
where I've included pads to install a National FDC. The 18c452 has enough
RAM. I've also added 128 kbytes of external capacitor backed static ram.
So, I guess I just have to study the FDC datasheet, ap notes, BIOS and
DOS documentation!
       I still like the FDC over alternatives (like zip drive) because of drive
and media costs. Also, the amount of stuff we're storing will easily fit
on an FDC.

Harold

On Sat, 29 Jul 2000 10:23:28 Snail Instruments <TakeThisOuTsnailspamspam_OUTiol.cz> writes:
{Quote hidden}

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'[EE]: [Photo]: PIC & IDE HD based mass storage for'
2000\07\30@024131 by Javier Grijalba

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Hi
You could use the AT90S8515,  it can be used with an external SRAM < 64K
It has 8KB eeprom, 32 io lines, SPI, UART, PWM, 8Mhz = 8 Mips, etc
Its very cheap aprox $8 in low quantities
Bye
Javier
PD I was planning to interface it with a CDROM or HD, too !

{Original Message removed}

2000\07\30@091441 by wzab

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picon face
On Sat, Jul 29, 2000 at 02:17:49AM -0300, Javier Grijalba wrote:

> You could use the AT90S8515,  it can be used with an external SRAM < 64K
> It has 8KB eeprom, 32 io lines, SPI, UART, PWM, 8Mhz = 8 Mips, etc
> Its very cheap aprox $8 in low quantities
> Bye
> Javier
> PD I was planning to interface it with a CDROM or HD, too !

So I'm afraid the project is unlikely to be PIC based :-(
(I've found one only 18C... PIC which seems to be capable to match
the requirements. Unfortunatly it is still the "Future Product").

The main problem is that the "photopc" protocol (described in
http://www.average.org/digicam/ ) allows the ca. 2KB packets, which
have to be buffered in the uC's memory (no flow control, so we can not write
the data to HD after each 512 bytes).

The AT90S8515 could be a good choice, but is it supported by SDCC or any
other free & open source C compiler?

I've also received a few questions/comments about the method for sending the
archived photos to the PC. Now I can see three possibilities:

1) Sending the data through the RS232 (used also for connecting of digital
  camera) - easy but slow. The device could just emulate the digital
  camera?
2) Sending the data with the proprietary protocol, using the printer port.
  The transfer rate could be much higher...
3) If the device would be mounted in a removable HD case, then it could be
  be used as a normal HD (however with proprietary very simplified
  filesystem). Servicing of such HD should be very easy in Linux, but I
  don't know how it would work with M$ Windows. I had bad experiences with
  non standard formats on FD's and HD's used with Windows. Sometimes the
  "OS" just proposed the reformating of "damaged" media =:-(.

The 3rd solution would be the best regarding the transfer rate. The IDE bus
should be connected both to the case's IDE connector and to the uC. The
switch should be provided to automaticaly force the uC's pins used for
driving IDE to go into high impedance state when devices is placed in the
PC's slot.
--
                       Thanks again for all the comments & suggestions
                       Wojciech Zabolotny
                       http://www.ise.pw.edu.pl/~wzab

When buying any hardware, ask the dealer if it is Open Source friendly!!!
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'[EE]: [Photo]: PIC & IDE HD based mass storage for'
2000\08\02@035413 by Javier Grijalba
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Yes, GCC-AVR is a free C compiler !! There are a few others also
Bye
Javier

----- Original Message -----
From: Wojtek Zabolotny <RemoveMEwzabspamspamSTOPspamISE.PW.EDU.PL>
To: <.....PICLISTEraseMEspamMITVMA.MIT.EDU>
Sent: Sunday, July 30, 2000 10:11 AM
Subject: Re: [EE]: [Photo]: PIC & IDE HD based mass storage for digital
photocamera


{Quote hidden}

write
> the data to HD after each 512 bytes).
>
> The AT90S8515 could be a good choice, but is it supported by SDCC or any
> other free & open source C compiler?
>
> I've also received a few questions/comments about the method for sending
the
{Quote hidden}

with
>    non standard formats on FD's and HD's used with Windows. Sometimes the
>    "OS" just proposed the reformating of "damaged" media =:-(.
>
> The 3rd solution would be the best regarding the transfer rate. The IDE
bus
{Quote hidden}

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'[PIC]: Simplest MAX232 interface for PIC & WLoader'
2000\08\05@190526 by wzab

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picon face
Hi All!

In my PIC16F877 based board I'd like to use the WLoader
( http://www.xs4all.nl/~wf/wouter/pic/wloader ) to update the code.
Because the PIC's UART will be used for communication with REALLY RS232C
compliant devices (not just PC), I need to place the MAX232 on the board.
However I'll get two spare channels available for WLoader (no handshake is
used).
Having read the WLoader's documentation, I've stated, that the interface
circuit may be simplified, if the polarity of WLoader's communication pin
is changed (the original interface used all four level converters for
WLoader).

This is the proposed interface:
                _____________
RS232 input  ----|RIN1  ROUT1|--- PIC RC7/RX
RS232 output ----|TOUT1  TIN1|--- PIC RC6/TX
                |           |
RS in (to PC)----|RIN2  ROUT2|---+====+--+
                |           |  R1 (10k) |
RS out(to PC)----|TOUT2  TIN2|-----------+--- PIC E2 (WLoader PIN)
                -------------
                   MAX232

It seems to me that changing the 91st line of wloader.asm source
from:
 port_define PIN, active_low, in_out, async_pin
to:
 port_define PIN, active_high, in_out, async_pin
should do the trick...

Is it really so simple, or have I missed something?

BTW. Has someone tried to port the WISP.EXE to Linux?
--
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                       Wojciech Zabolotny
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2000\08\06@041514 by wzab

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On Sun, Aug 06, 2000 at 01:02:29AM +0200, Wojtek Zabolotny wrote:
>
> This is the proposed interface:
>                  _____________
> RS232 input  ----|RIN1  ROUT1|--- PIC RC7/RX
> RS232 output ----|TOUT1  TIN1|--- PIC RC6/TX
>                  |           |
> RS in (to PC)----|RIN2  ROUT2|---+====+--+
>                  |           |  R1 (10k) |
> RS out(to PC)----|TOUT2  TIN2|-----------+--- PIC E2 (WLoader PIN)
>                  -------------
>                     MAX232

Ooops, I've forgotten about the pull-up:

So it should look out like this:
                  _____________
 RS232 input  ----|RIN1  ROUT1|--- PIC RC7/RX
 RS232 output ----|TOUT1  TIN1|--- PIC RC6/TX
                  |           |
 RS in (to PC)--+-|RIN2  ROUT2|---+====+--+
       R2 (4k7) | |           |  R1 (10k) |
+5V-|>|-+====+---+ |           |
 RS out(to PC)----|TOUT2  TIN2|-----------+--- PIC E2 (WLoader PIN)
                  -------------
                    MAX232

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2000\08\07@064948 by Vasile Surducan

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 Hi Wojtek, Hi Wouter

 Wouter, as you see, the same problem and other people !

 Wojtek, first release of wloader it works on standard
communication pins of 877 RC6 and RC7  , this is not available
now from Wouter's page. As my tests on various computers and
232 interfaces
( 16450, 16550 ) shows the problem is not the interface but delays
between receive and send command bit's ( and sometimes the
levels of signals on Rx-Tx pic pin ) . So I thinked also at your
solution...I'm currently using a non-inverting RS232 made from
1488 and 1489 tied together through a diode to PIC communication
pin and a 1nF capacitor to ground. But as I told you it doesn't work
correctly only on some computers ( I've tested on 5 different
computers...)
 Vasile



On 6 Aug 00, at 10:14, Wojtek Zabolotny wrote:


{Quote hidden}

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email:.....vasileEraseMEspaml30.itim-cj.ro
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'[PICLIST] [PIC & BS2] Liaison LCD 2 fils'
2000\09\08@041109 by weslay
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Bonjours,

Je recherche un exemple de programme en basic pour afficher une chaine de caractères sur un afficheur LCD 1 ligne, à partir d'un BS2 ou un pic 16F84.

La liaison STAMP ----- LCD est en 2 fils ( data + strobe ) d'après le schéma que j'ai trouvé sur le site:   http://www.myke.com/engres/lcd.htm

l'exemple fourni est en assembleur et je ne sais pas le traduire en basic

Merci à tous

Jacky

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'[PICLIST] [PIC & BS2] liason 2fils LCD'
2000\09\08@041330 by Jacky Joulin

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Bonjours,

Je recherche un exemple de programme en basic pour afficher une chaine de caractères sur un afficheur LCD 1 ligne, à partir d'un BS2 ou un pic 16F84.

La liaison STAMP ----- LCD est en 2 fils ( data + strobe ) d'après le schéma que j'ai trouvé sur le site:   http://www.myke.com/engres/lcd.htm

l'exemple fourni est en assembleur et je ne sais pas le traduire en basic

Merci à tous

Jacky

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'[PIC]: EE challenge PIC &&12V Battery'
2001\01\11@063629 by Germain Morbe
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Hello,

has anyone a LOW COST / LOW CURRENT idea that could help solving the
following alimentation problem?

A 16C505 or 12C508 shall be used as an ecoder for a 12V battery powered 3
button handheld transmitter. Because of the needed code completion feature
after button release, the power must be present permanently / resp. as long
as the PIC needs it.

The two approaches i see are:

a) use a very low power 5V regulator which is comparable expensive.  That
way the PIC could wakeup from sleep at button activation for as long time as
needed to complete a message after release of the button.

b) use a low cost 7805 regulator or a zener which draws to much current to
be allways on. Thus, the buttons need to switch the power directly and the
PIC needs to hold the power in the ON-state via some transistors. After
completion it could cut itself and also the stabilizing circuit from power
by releasing the transistors.

Is there a third possibility i dont think of?  I feel that from the two
mentioned either has its drawbacks in a low cost radio control? What would
the gurus advice?

Germain Morbe

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2001\01\11@070157 by Jinx

face picon face
This is asked from time to time, and you should find a few threads
in the archives

> a) use a very low power 5V regulator which is comparable expensive.

What do you call expensive ? Seiko, Linear, and National all do
ranges of low power LDO regulators. As many (including me) have
found though, you may have to buy fairly large quantities to get a
decent price

If you've got a few to make, then a circuit that requires much more
assembly than a simple regulator may cost more in labour

What is your "12V" ? Is it true 12V or a nominal 12V (perhaps 13.8V).
LP/LDO regs don't always like > actual 12V

> Is there a third possibility i dont think of?  I feel that from the two
> mentioned either has its drawbacks in a low cost radio control?

I use the LP2951, which can be turned on/off by a single pin. I also
use Seiko LDO regs when I can get them, and Seiko S81250 to
replace 78L05. How much transmitting power do you need ?

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2001\01\11@074818 by Germain Morbe

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Jinx,

we buy a seiko ldo that do 100mA, it is about 0,23$ at 10k pcs.
Its not that cheap but its main drawback is its poor availability over time.
Once you have decided for such a part you often cannot change on the fly,
especially at higher volumes.
That is why our company would love to use no specialized parts at all which
is often not a technical but a vital decision. I myself prefer state of the
art components when needed.

In generally i agree to you labour cost arguments, only because its all
surface mount, labour cost is not that high.

The battery is a small 23A type, usually its voltage not much higher than
12V.

We are allowed to radiate up to +10 dBm at 433MHz here in europe, but
usually with a poor antenna you will be happy to reach 0dBm if you put 100mW
in.

For the moment i tend to the ldo approach also. Who is building the LP2951?

Germain

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2001\01\11@075858 by Fred Bailey

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In  building alarm systems, two wires are used to communicate to, and power all
the sensors on the line. A large amount of capacitance is used on each sensor to
hold power during the communication period.

I suggest you use a capacitor that will hold power while transmitting is active.

Best Regards,

Fred

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2001\01\11@090504 by M. Adam Davis

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This may not fit into your design, but there are low power switching
regulators which require fewer components than a typical switching design,
and feature shut-down modes which reduce current draw to the uA range.  A
button could supply enough power to the shutdown to start it up, and the
uC could shut it down as long as the button is not pressed.

You might try this one, for instance...
http://dbserv.maxim-ic.com/quick_view2.cfm?pdf_num=1155&Fam=DCDC_All&TREE=PowerSupplies.asp&HP=PowerSupplies.cfm

-Adam

Germain Morbe wrote:
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2001\01\11@110018 by David VanHorn

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Ignoring the regulator, have the pushbutton supply input to the regulator.
Once the pic wakes up, it can turn on a PNP transistor, which is in
paralell with the button, to keep it's power up as long as it likes. When
it's done, just turn off the transistor.  This will take a pair of
transistors, but that's only pennies, and you won't have any availability
problems.

Now, solve the regulator as a separate problem.
Since it's input is cut off most of the time, its efficiency becomes much
less important.
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2001\01\11@110028 by Martin Hill

picon face
that's exactly what I did, using a MAX619 chip, just needs two .1uF caps.
This was to get 5v from two AA cells though, but the principle is the
same.  A button press activates it, then a pin on the pic holds it on
until it decides to turn it off.  Needs a bit of thinking about or the pic
will think the button is permanently pressed if you just drive the
same line.  Nothing a few transistors can't fix.

Martin


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2001\01\11@114553 by M. Adam Davis

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Unfortunately I couldn't find a capacitor drop down regulator, the one I
mentioned requires a coil and a diode (as well as a few caps).

As far as the button, you can use a diode to prevent the pic from
misreading the input:

vbatt+------+
           * |
             |--
           * |
           |
vneg--/\/\--+---|>|---+-------To shutdown (high=on)
           |         |
       ____|_________|_______
      |    1         2       |
      |       PIC            |

When the button is pressed it supplies enough power to bring shutdown
high, the pic wakes up, and brings I/O 2 high.  At that point it doesn't
matter whether the button is pressed, except the pic cannot turn the
regulator off if the button is pressed (in that case, bring pin 2 low, and
go to sleep - the regulator will shut off when the button is no longer
pressed).

You may have to tie the shutdown low - many regulators have it tied high
internally through a very weak resister.

-Adam

Martin Hill wrote:
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2001\01\11@130625 by Roman Black

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Germain Morbe wrote:
{Quote hidden}

I'm not a remote guru, but it does seem the max
priority is to conserve the battery.

I would use the buttons to switch the entire
power to the PIC (and regulator), and use a fet
or transistor to keep the power on under PIC
control until it decides it is finished doing
the task.

For the 3 button dilemma, I would use 3 diodes,
one from each button to the PIC power Vdd, this
is the common for all three buttons of course.
Then each button is also connected to one PIC
input pin. This will allow any button to power
the PIC, and also activate its own input pin.

The diodes will drop 0.6v, assuming cheap diodes,
but you only have to get the PIC running long
enough for it to turn the transistor on, and
then you have full power anyway. :o)
-Roman

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2001\01\11@132048 by Don Hyde

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The PIC is pretty tolerant of voltage variations, so it could be supplied
via a zener.  I imagine that the radio is a little more critical, so it
could be supplied by a regulator that is switched on by the PIC (easiest is
a PNP transistor with collector to +12V, emitter to regulator, base to
open-drain PIC output pin).  That way the regulator which supplies the radio
can be a simple 78L05, which has lousy quiescent current but is cheap.

> {Original Message removed}

2001\01\11@144201 by steve

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> Is there a third possibility i dont think of?  I feel that from the two
> mentioned either has its drawbacks in a low cost radio control? What would
> the gurus advice?

I don't know what it costs, but is PIC16HV540 worth considering ?
It may end up being cheaper to use that and no regulator.

Steve.
======================================================
Steve Baldwin                Electronic Product Design
TLA Microsystems Ltd         Microcontroller Specialists
PO Box 15-680, New Lynn      http://www.tla.co.nz
Auckland, New Zealand        ph  +64 9 820-2221
email: TakeThisOuTstevebTakeThisOuTspamRemoveMEtla.co.nz      fax +64 9 820-1929
======================================================

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2001\01\11@145830 by James Paul

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Germain,

Just an observation on my part and a bit of a tangent from your
original question, but regarding the RF power output of your unit.
You state that you are allowed a mx of +10dbm which is 10mw, correct?
And that you'd be happy to get 0dbm, which is 1mw correct?  And that
this could be had with only 100mw input.  Is this input to the entire
unit, or only to the RF section?  If to the whole unit, then what
portion of this input goes to the RF section?   If this is to the RF
section only, then you must have a very ineffecient RF section to be
sure.  It seems to me that even the most ineffecient transmitter RF
power output driver/amplifier can convert at a reat of 30% or so.
At best, you are getting about 10% and at worst about 1%.  Is this
correct, or am I miscalculating the numbers here?  Please advise.

                                              Regards,

                                                Jim





On Thu, 11 January 2001, Germain Morbe wrote:

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2001\01\11@150045 by M. Adam Davis

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I hadn't even thought of that!  This might be the best way to do things,
actually.

It has a wake up on pin chaange, so you can sleep the entire time without
using the watch dog to wake you up for polling.  Not only that, but it has
high voltage outputs which might help you with your transmitter design.
You could power your transmitter from the pic.

-Adam

Steve Baldwin wrote:
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'[PICLIST] Fw: [PIC]: EE challenge PIC && 12V'
2001\01\11@153131 by GMorbe

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Hi all,

thanks for your comments that far. Most of your suggestions tend more or
less to eitherone of my initial concepts except using a reg with a shutdn
capability which is a third idea.

From the standpoint of a simple clean concept one should probably take the
5V LDO. But each of the three concepts are fairly easy to implement. Because
it needs to be Low Cost i tend to leave the decision to the pocket
calculator.

By taking a cheap reg or even a zener then add up 2 transistors, 3 diodes
and some passives, i think there will be no big difference left compared to
the LDO, but it needs to be calculated more exactly to say. The discrete
approach however relies on standard components only.

Germain

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'[PIC]: EE challeng PIC && 12V'
2001\01\11@160508 by GMorbe

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Adam,

of course the HV540 is worth a look for that purpose. Because we produce a
whole bunch of different remote controls and receivers we already use the
HV540 on some other designs. The only problem with it is its price. It is
about $2.0 at medium volumes. 1 to 5k pcs. As one of our suppliers explained
us, that chip is a modified version of the 1st 16C54 core based on 1.2
micron technology. Additionally it seems to be bondered together with a
regulator in the same plastic but not integrated on silicon. This makes it
that expensive we have been told.

Germain

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2001\01\11@160713 by GMorbe

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Paul,

it looks that your calculations are correct. The 100mW is total but most of
it (about 85%) is even used up by the rf. One should expect to get at least
20mW rf power and really, directly coupled to the 50 ohm input of a spectrum
analyzer you will get even more than that.

The real big difference arises out of mismaching messured rf output power
with ERP.
Since a 1/4 wavelength aerial which would achieve good performance at 433Mhz
is about 6 to 7 inch in length, it is not that handy to put it in your
pocket. Therefore common remote designs rely on pcb antennas which are small
in size but real worse in performance.

As their characteristics depend only on the pcb layout, you should be happy
to achieve a radiated power of 1 to 3% of your actual rf input after lets
say 3 to 5 design tries.

Germain

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'[PICLIST] Fw: [PIC]: EE challenge PIC && 12V'
2001\01\12@064631 by Roman Black

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GMorbe wrote:
>
> Hi all,
>
>  thanks for your comments that far. Most of your suggestions tend more or
> less to eitherone of my initial concepts except using a reg with a shutdn
> capability which is a third idea.

> By taking a cheap reg or even a zener then add up 2 transistors, 3 diodes
> and some passives, i think there will be no big difference left compared to
> the LDO, but it needs to be calculated more exactly to say. The discrete
> approach however relies on standard components only.

1. I think you can do it with one transistor/fet. Maybe on
the -ve leg of the battery with some lateral thinking.

2. Diodes and transistor VERY cheap in large quantities,
especially when you factor in the ability to buy broad
spec of parts of reasonable compatibiity, cheapest
tender, specials that month, etc etc. Much better for
your manufacturer, and safer when supplies are
unpredictable.

3. I would look at running the transmittrer section
straight from the battery in a way that it is normally
off. This means your reg only has to do the pic.
So you can use the tiniest of zeners for the reg.

4. I would definitely choose an option that is
completely open circuit when off. Those 23A 12v
batteries are hard to get and expensive. Very
annoying in remotes that go bad when you haven't
used them for a while. We sell these batteries,
to lots of annoyed people I might add! ;o)
-Roman

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2001\01\12@075306 by Germain Morbe

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Hello Roman,

i agree to all of your suggestions except that you assume it might be
possible to keep the power with only 1 transistor. At experiments i made
years ago about that, i found no solution for the following behavior.
Imagine you use an NPN in the negative line. As soon as the pic completed
its task it cuts itself from the groundline by outputting a low potential to
the NPNs base. This stops the current flow and as a result to that the whole
circuit floats against the positve potential. Also the portpin to the NPNs
base. It is no longer able to output a zero but rises up to 12V which in
fact turns the NPN on again resp. will not turn it off at all.

Germain

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2001\01\12@081142 by Roman Black

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Germain Morbe wrote:
>
> Hello Roman,
>
> i agree to all of your suggestions except that you assume it might be
> possible to keep the power with only 1 transistor. At experiments i made
> years ago about that, i found no solution for the following behavior.
> Imagine you use an NPN in the negative line. As soon as the pic completed
> its task it cuts itself from the groundline by outputting a low potential to
> the NPNs base. This stops the current flow and as a result to that the whole
> circuit floats against the positve potential. Also the portpin to the NPNs
> base. It is no longer able to output a zero but rises up to 12V which in
> fact turns the NPN on again resp. will not turn it off at all.

Ha ha! I didn't say it was easy, just that it
should be possible. That's why it's a challenge.
I can think of a few ways to start with, that
*might* lead to a solution, but I'm curious to
see what the experts come up with. :o)
-Roman

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'[PIC]: EE challenge PIC &&12V Battery'
2001\01\12@140257 by Peter L. Peres

picon face
You can save on transistors and switchoff logic by using a capacitance
multiplier with a single transistor. This saves a PIC pin (required to
hold the power on) (I suspect you are using a 8-pin PIC). The required
capacitor will be small, too.

Peter

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'[PICLIST] Fw: [PIC]: EE challenge PIC && 12V'
2001\01\12@140307 by Peter L. Peres

picon face
Just before you finish calculating:

You can set the PIC to sleep and wake up to check the keys (or keypress
wakeup), and use a LDO regulator that works all the time. This leads to a
minimum parts solution.

Peter

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'[PIC]: EE challenge PIC &&12V Battery'
2001\01\12@140312 by Peter L. Peres

picon face
The poor efficiency of some rf tx modules is dued to the bandwidth
requirements and to on board PLL (if any). The devices run in class A or
AB at best. Class C is not usable at those power levels without using
expensive filters afterwards. Getting 1mW with 100mW input is about
standard. 100mW input is 5V, 20mA if you are wondering. If you think that
this is inefficient, compare to a PC computer or to a laser ;) Of course
one can make expen$ive modules with 60% or better efficiency.

Peter

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2001\01\13@022716 by Roman Black

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Peter L. Peres wrote:
>
> You can save on transistors and switchoff logic by using a capacitance
> multiplier with a single transistor. This saves a PIC pin (required to
> hold the power on) (I suspect you are using a 8-pin PIC). The required
> capacitor will be small, too.

Very clever! I had thought of a way to get
the PIC to pulse a line capacitor coupled to
the transistor, to give a turn on period and
get rid of the bias problems when just using
one transistor for the power.

Your way is better, and has less parts count
and much simpler.

What about getting rid of the transistor
all together, just charging a large cap with
the button, which then takes X time to discharge
powering the zener reg and PIC?? Assuming the
PIC draws regular amount of current it would
give predictable time to go down. Hmm. Maybe
battery voltage could cause problems as
battery starts getting flat?.. But this would
be even simpler. :o)
-Roman

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2001\01\14@171733 by Peter L. Peres

picon face
>What about getting rid of the transistor
>all together, just charging a large cap with
>the button, which then takes X time to discharge

Only one small snag: capacitor size. When I do things like this I fit them
in a keyfob usually ;-)

Peter

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'[PIC]: EE challenge PIC && 12V battery'
2001\01\14@183056 by GMorbe

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part 1 596 bytes content-type:text/plain; (decoded 7bit)

Hello Roman, All

I think i go the discrete approach because of components availability
reasons.
The use of a capacitor for the hold time is clever but i dont like it,
because the PIC would die down slowly by discharge unless you take special
action to avoid this.
Meanwhile i found a solution around the diodes to decouple the button
information from their switch on function. By connecting the buttons to
the - potential its possible to decouple them with resistors only. The
values of them needs to be well defined however. See my picture.

Germain Morbe




part 2 7068 bytes content-type:image/gif; (decode)


part 3 131 bytes
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2001\01\14@215128 by Dan Michaels

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GMorbe wrote:
>Attachment Converted: C:\WIN31APP\EUDORA\ATTACH\PICTX.gif
>

I wonder that you might not have a minor problem with your ckt.
The typical leakage current into PIC input pins is ~1uA, so 10M
series Rs would seem to be too high.

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2001\01\15@012946 by Germain Morbe

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Dan,

you may be right, the values have to be well defined. The shown values are
not tested yet, but are a rough calculation to start with. See the time
stamp of my posting. Thank you, i will check it this morning. :)

Germain Morbe

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2001\01\15@022721 by Roman Black

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GMorbe wrote:
>
> Hello Roman, All
>
> I think i go the discrete approach because of components availability
> reasons.
> The use of a capacitor for the hold time is clever but i dont like it,
> because the PIC would die down slowly by discharge unless you take special
> action to avoid this.
> Meanwhile i found a solution around the diodes to decouple the button
> information from their switch on function. By connecting the buttons to
> the - potential its possible to decouple them with resistors only. The
> values of them needs to be well defined however. See my picture.
>
> Germain Morbe

Hi Germain. I'm not sure I like the design. Your 12v
battery voltage is permanently connected to the two
PIC pins, which:
1. is way out of voltage spec!!
2. will drain battery into the PIC protection diodes.

Why not replace the 10M with 1N4148 glass diodes, these
are cheaper and smaller than resistors, and will
solve the two problems...
-Roman

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2001\01\15@034910 by Michael Rigby-Jones

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{Quote hidden}

He would also need to provide pullups from the PIC side of the diodes to
Vcc, otherwise there would be nothing to pull the PIC pins to a logic one if
a button wasn't pressed.

Mike

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2001\01\15@052040 by Simon Nield

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you can ditch the left hand transistor and it's associated bits if you turn one of the button
reading ports round to be an output once you have read it. Just use the PIC pin to pull the line
low... would need to ditch the 10M resistors too though.

replacing the 10Ks with say 220k would reduce off current, if your transistor has enough gain.

connecting 1n4148s or similar from the button pins (anode) to vcc of the pic (cathode) will ensure
the voltage on the pic pins remains within spec, although if you check the datasheet hard enough you
might find that the protection diodes are able to perform this function safely (personally i would
use external diodes)

(the radio is constantly powered at the moment btw, which I assume is just an error in your
schematic ?)

a handy tip for optimising low power stuff: measure the current being drawn from the battery with a
well calibrated meter and hack your code to make the unit operate either constantly on or off (you
need to do both) then try disconnecting bits of the circuit you think you can optimise and see if
they actually make a significant change to the current draw. if there is no big change then don't
waste your time. (useful for instance in verifying if the 'off' current of your circuit is
acceptable / improvable)

regards,
Simon

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2001\01\15@092127 by Germain Morbe

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Simon,

according to Roman ( and he4s right by the way ) the portpins are not real
oct because of the protection diodes as you found also. Therefore pulling
the base low after a button was pressed would work, but releasing it to high
state ( what means 12V in this case ) would probably not. Also changing the
10M resistors to a significant lower value would result in exessive current
drain while in off state.

Roman, i will decide to use the diodes or not after i finished my
messurements. I took the idea for the simplification out of a MCHIP appnote
about interfacing a pic to the AC powerline via just one resistor. I found
if  thatone worked my should also.

Germain

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2001\01\15@102012 by Simon Nield

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germain:
>but releasing it to high
>state ( what means 12V in this case ) would probably not.

doh. of course it wont. my apologies. could use could use a series diode to fix it of course, but
then the circuit complexity is creeping up again without offering any advantages over what you
already had.

regards,
Simon

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2001\01\15@163539 by Gennette, Bruce

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Be carefull with that one resistor to full AC voltage - you'll get away with
it on 110V RMS systems, but 230V (peak way over 400V) systems *WILL* destroy
the resistor in time.  The solution is to use 2 equal value resistors in
series so that each experiences less than 300V peak (their design limit).

This is a global discussion group so designs and FAQs *SHOULD* always take
into account that most of the world now uses the nominal 230V standard.
(Are you listening Microchip ?).

Bye.

> {Original Message removed}

2001\01\16@050620 by mike

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On Tue, 16 Jan 2001 08:36:46 +1100, you wrote:

>Be carefull with that one resistor to full AC voltage - you'll get away with
>it on 110V RMS systems, but 230V (peak way over 400V) systems *WILL* destroy
>the resistor in time.  The solution is to use 2 equal value resistors in
>series so that each experiences less than 300V peak (their design limit).
..or use metal glaze resistors, which are deigned for high voltage
use.
>This is a global discussion group so designs and FAQs *SHOULD* always take
>into account that most of the world now uses the nominal 230V standard.
>(Are you listening Microchip ?).

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'[PIC]: EE challenge PIC && 12V battery (fwd)'
2001\01\16@164340 by Peter L. Peres

picon face
part 1 89 bytes content-type:TEXT/PLAIN; CHARSET=US-ASCII
Now I've gotten to do (poor) a la minute analog designs. Sigh. See
attachement.

Peter


part 2 7312 bytes content-type:APPLICATION/PDF; name="sw-reg-del-pic.pdf" (decode)

part 3 105 bytes
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'[PICLIST] PIC & batteries'
2001\01\22@050205 by Andrea Aizza

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Hi,

I am going to use a PIC on a battery supplied card. I do not know what are
the possible batteries to choose, what are the differences and what is mean
life time of the battery (the order of magnitude). I imagine there are so
many possible batteries and that the lifetime of  the battery heavily
depends on the application. In this application the PIC needs to ''know''
the time thus there will be either a RTC chip or the PIC will be used as
clock. Do you have an idea of what is the order of duration for some
''standard'' batteries for this problem?

Thanks and Best Regards,

Andrea.

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2001\01\22@102156 by M. Adam Davis

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When faced with such a question I usually reach for my DigiKey catalog.
All their batteries have the mAH and voltage ratings.

First you need to give us an idea of what your power requirments are going
to be and whether you have any preferences as to battery type and number.
Would you like to use 4 AA cells?  Two lithium watch batteries? An N or
other camera battery?

Are you planning on using a regulator?  What current will your circuit
require?  Is there a voltage requirement as well, or can we assume the
3-5.5V range of a PIC?

For instance,
http://rocky.digikey.com/USCatalog/V3/554.PDF
shows some carbon-zinc and alkaline batteries.  The alkaline AA is rated
as lasting 170 hours on a 100ohm load.  This is 15mA for 170H, or 2.55AH
(ie, if you could safely draw one amp from it - it would last for 2.55
hours).  Its highest rated drain is 130mA, so you shouldn't draw more than
that.  This is your first check - find your current drain, and then look
at batteries that can deliver that rate.

Once you've done that you need to determine how long you want the product
to last.  If it takes 20mA, and you need it to last for 5 days, then you
need 20mA for 120Hrs.  This is 2.4AH, so 4 AA batteries would be able to
meet your needs.

-Adam

Andrea Aizza wrote:
{Quote hidden}

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2001\01\22@171803 by Germain Morbe

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> Hi,
>
> In this application the PIC needs to ''know''
> the time thus there will be either a RTC chip or the PIC will be used as
> clock. Do you have an idea of what is the order of duration for some
> ''standard'' batteries for this problem?
>

Hi Andrea,
the parameters for your battery are fairly easy to calculate once you have
an idea of how much current your application might consume. If you PIC has
not much more to do than counting time using an interrupt routine then your
current needs might well be under 10 microamps, even 2 microamps are
possible with a 3V supply. A not too bad 1.5V alkaline battery can have a
capacity of up to 1000mA/h. Using 2 of them for example gives you 3V at
1000mA/h. Your lifetime in hours is then CAPACITY divided by CURRENT e.g.

 1000mA/h
---------------   =  500.000 hours  ( or 100.000 hours at 10 microamps )
2 microamps

Fairly easy. Isnt it?

Germain Morbe

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2001\01\22@202717 by William Jacobs

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Check these sites

http://www.duracell.com/OEM/index.html
or
http://data.energizer.com/

Bill Jacobs

Andrea Aizza wrote:
{Quote hidden}

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2001\01\23@122642 by Don Hyde

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We have found lithium primary batteries to be very good (as have digital
camera makers).  They have low self-discharge, which means long shelf life,
low internal resistance, which means you can get several amps for a few
milliseconds every couple of hours and still last for years.  The digital
camera guys have built up the volume so that drugstores stock them (at a
pretty hefty price), but if you buy boxes of a hundred from a distributor,
they are much more reasonably priced.  The discharge curve is flat enough
that you can run a PIC off one without a regulator and still suck out just
about all the juice it has to offer.  On many batteries, the last half of
those rated mAH comes at such a low voltage that you can't get a processor
to run off them.

Our most common is DL123 which is 1/3A size, for about $8-9 at the
Walgreen's next door or around $3 from a distributor.  They go from around
3.2V new to about 2.1V flat dead, and will deliver as much as 10A.  10A
sacrifices some mAH to internal resistance, but an amp or two can be had
without significantly decreasing the total capacity (though of course you
will use it up pretty quickly).

We routinely run radios for 5 years, where the PIC sleeps most of the time
and wakes up several times a day to turn on the radio and send a 30 mS
message.

> {Original Message removed}


'[PICLIST] pic & radio frequency'
2001\02\04@194915 by Jose Antonio Gracia Negre
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For a project of remote control I need directions pages that deal with
the subject the shipment and reception of data between pic and PC by
means of radio frequency
by means of radio frequency, but that can modify I the code


Any help would be much appreciated.

Many thanks

Josi A. Gracia

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2001\02\05@190958 by Jose Antonio Gracia Negre

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For a project of remote control I need directions pages that deal with
the subject the shipment and reception of data between pic and PC by
means of radio frequency, but that can modify I the code

Any help would be much appreciated.

Many thanks

Josi A. Gracia

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2001\02\05@193308 by Philip Martin

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During my investigations into my current project, radio remote control, I
have come across the very thing for you. Go to http://www.rfsolutions.co.uk and
look at the data sheets on their Radio Evaluation Kit. There is a section
there on a PC to PC data link, including the use of a 16C73A Pic. You will
also find some useful data on Microchips web site if you look at the KeeLoq
Devices section. These chips are used in both RF and IR data channel coding.

Philip Martin.


{Original Message removed}


'[pic]: pic & morse code trainer'
2001\08\01@064858 by Jean-Marie ON4CBS
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hello

i want to make a morsecode trainer with a pic(16f84)

the random codes must be visual on a lcd display
speed and space must be variable

is there anybody who worked already on this matter?


73 jean-marie on4cbs

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2001\08\01@104240 by David VanHorn

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At 09:01 AM 8/1/01 +0200, Jean-Marie ON4CBS wrote:
>hello
>
>i want to make a morsecode trainer with a pic(16f84)
>
>the random codes must be visual on a lcd display
>speed and space must be variable
>
>is there anybody who worked already on this matter?

I had other goals, but on my page, under microcontrollers, you'll find the
source for an F84 controlled transmitter. Among other things, there's a
text to morse engine with variable transmit speed.

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2001\08\02@193636 by Ian Hynes

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Jean-Marie ON4CBS wrote:
>
> hello
>
> i want to make a morsecode trainer with a pic(16f84)
>
> the random codes must be visual on a lcd display
> speed and space must be variable
>
> is there anybody who worked already on this matter?
>
> 73 jean-marie on4cbs

I haven't done it in PIC but here's a programme in PASCAL that runs on
a PC and bleeps the morse thru  the internal speaker. It's variable
speed but only does one sentence which you type in. Hopefully it'll be
good for some ideas?
Regards - Ian

;****************************************

PROGRAM SendMors;
{
DATE    : 26.12.99;
AUTHOR  : Ian Hynes
PURPOSE : To test the Morse_Tx procedure.
}

TYPE   String255 = STRING [255];
      String80  = STRING [80];

VAR    Message            : String255;
      Flag               : char;
      SpeedSwitch        : boolean;
      CodeRate, TestFreq : integer;

{$I ..\PASCAL\LIBPRC\Morse_Tx.PRC}

BEGIN
 ClrScr;
 { Best CodeRate = 15, TestFreq = 1000. }
 CodeRate := 10; TestFreq := 1000;
 writeln ('*** This is MORSE CODE #1 ***');
 writeln;

 write ('Do you want to send (F)ast, (S)low  or (R)eal Slow ? ');
 readln (Flag); Flag := UpCase (Flag);
 IF   Flag IN ['F', 'S', 'R']
 THEN CASE Flag OF
           'F' : CodeRate := 20;
           'S' : CodeRate := 10;
           'R' : CodeRate := 5
      END   { ... of CASE. }
 ELSE BEGIN
        writeln ('A bad entry ! Setting Code Rate to FAST');
        CodeRate := 15
      END;

 writeln;
 Flag := ' ';
 FillChar (Message, 255, Flag);
 Message := 'Numbered, numbered, weighed and divided.';

 writeln ('Enter your message ... ');
 writeln;
 readln (Message);
 writeln;
 writeln ('Hit any key to terminate transmission ... ');

 REPEAT
   Morse_Tx (Message, TestFreq, CodeRate);
 UNTIL KeyPressed;

 writeln (' ... OK. Transmission is ended. ');
END.

;**************************

PROCEDURE Morse_Tx (PlainText : String255;
                   ToneFrequency : integer; CodeSpeed : integer);
{ DATE    : 23.x.99; REF : Duntemann, pg. 52
 PURPOSE : To convert a text string into audible morse.
 GLOBALS : TYPE String255 = STRING [255];
                String80  = STRING [80];
}

VAR   I, ToneLength, DitLength : integer;
     CodeChar                 : String80;
     BlendNextTwo             : boolean;

{...................................................}

PROCEDURE Morse (CodeChar : String80);

VAR   I : integer;

BEGIN     { Of Morse ... }
 FOR I := 1 TO Length (CodeChar) DO
 BEGIN
   IF   CodeChar [1] IN [ '.', '-']
   THEN BEGIN
          IF   CodeChar [I] = '.'
          THEN ToneLength := DitLength
          ELSE ToneLength := DitLength * 3;
          Sound (ToneFrequency);
          Delay (ToneLength);
          NoSound;
          Delay (DitLength)
        END
 END
END;      { ... of Morse. }

{...................................................}

BEGIN     { Of Morse_Tx ... }
 BlendNextTwo := FALSE;
 IF CodeSpeed = 0 THEN EXIT; { Catch duff entry ... }
 DitLength := ROUND ((1.2 / CodeSpeed) * 1000);
 FOR I := 1 TO Length (PlainText) DO
   IF   PlainText [I] = '*'
   THEN BlendNextTwo := TRUE
   ELSE BEGIN    { Of Case-Loop ... }
          PlainText [I] := UpCase (PlainText [I]);
          Case PlainText [I] OF
               'A' : CodeChar := '.-';
               'B' : CodeChar := '-...';
               'C' : CodeChar := '-.-.';
               'D' : CodeChar := '-..';
               'E' : CodeChar := '.';
               'F' : CodeChar := '..-.';
               'G' : CodeChar := '--.';
               'H' : CodeChar := '....';
               'I' : CodeChar := '..';
               'J' : CodeChar := '.---';
               'K' : CodeChar := '-.-';
               'L' : CodeChar := '.-..';
               'M' : CodeChar := '--';
               'N' : CodeChar := '-.';
               'O' : CodeChar := '---';
               'P' : CodeChar := '.--.';
               'Q' : CodeChar := '--.-';
               'R' : CodeChar := '.-.';
               'S' : CodeChar := '...';
               'T' : CodeChar := '-';
               'U' : CodeChar := '..-';
               'V' : CodeChar := '...-';
               'W' : CodeChar := '.--';
               'X' : CodeChar := '-..-';
               'Y' : CodeChar := '-.--';
               'Z' : CodeChar := '--..';
               '1' : CodeChar := '.----';
               '2' : CodeChar := '..---';
               '3' : CodeChar := '...--';
               '4' : CodeChar := '....';
               '5' : CodeChar := '.....';
               '6' : CodeChar := '-....';
               '7' : CodeChar := '--...';
               '8' : CodeChar := '---..';
               '9' : CodeChar := '----.';
               '0' : CodeChar := '-----';
               '?' : CodeChar := '..--..';
               '.' : CodeChar := '.-.-.-';
               ',' : CodeChar := '--..--';
               '/' : CodeChar := '-..-.';
               '\' : CodeChar := '.-..-';
               '$' : Codechar := '...-..-';
               '-' : CodeChar := '-....-'
            ELSE CodeChar := ''
          END;      { .. of Case. }
          Morse (CodeChar);
          IF NOT BlendNextTwo THEN Delay (DitLength * 2);
          BlendNextTwo := FALSE;
          IF KeyPressed THEN EXIT
        END         { ... of Case-Loop. }
END;                 { ... of Morse_Tx. }

>

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'[PIC]: David Tait's ParPic & SerPic'
2001\09\26@213826 by XChet
picon face
Are they good enough to program 12C5XX and 16C series
PICs?

http://www.nexuscomputing.com/~picarchive/icp84.html

The page also has the programming software? Is anyone
using it?

Thanks.

=====
Thanks,

XChet

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'[PICLIST] cheapest flash pic & where?'
2001\10\11@161056 by Assembly Wizard
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OK.  I have built a general pic programmer, with a 5V and 13.5V, regulated external, power supply.

I am new to pic's.  I am a proficient programmer in Intel(IBM PC)Assembly Language(TASM), C+(Borland Builder) and Pascal(Borland TurboPascal).

I wish to experiment with pic programming, my question is this:  What is the cheapest flash pic(electrically erasable, and can be programmed multiple times) and, where can I get it in small quanties?


Warmest regards,
Brett L. Ostrom
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2001\10\11@163246 by Brent Brown

picon face
> OK.  I have built a general pic programmer, with a 5V and 13.5V,
> regulated external, power supply.
>
> I am new to pic's.  I am a proficient programmer in Intel(IBM
> PC)Assembly Language(TASM), C+(Borland Builder) and Pascal(Borland
> TurboPascal).
>
> I wish to experiment with pic programming, my question is this:  What
> is the cheapest flash pic(electrically erasable, and can be programmed
> multiple times) and, where can I get it in small quanties?
>
>
> Warmest regards,
> Brett L. Ostrom

I would reccomend to start with the PIC16F84 and the free Hi-Tech
C compiler (limited to the PIC16x84 series). The PIC16F627 and
628 are cheaper (the cheapest FLASH PICs I think) and have some
really cool features, but then you'd be looking to buy a compiler.
There should be dozens of places to get an 'F84 from - local
electronics shops often sell them or buy it off the web from
someone like digikey.

Brent Brown
Electronic Design Solutions
16 English Street
Hamilton, New Zealand
Ph/fax: +64 7 849 0069
Mobile/text: 025 334 069
eMail:  EraseMEbrent.brownEraseMEspamclear.net.nz

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2001\10\11@203120 by Ivey Cole

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Being you are familiar with Assembly language, why not use the FREE assembler from
Microchip which is included in MPLAB and available separately.  The instruction set is
very learn.

On Fri, 12 Oct 2001 09:29:38 +1300, Brent Brown wrote:

{Quote hidden}

Ivey Cole spamicolespamonr.com

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2001\10\12@135527 by uter van ooijen & floortje hanneman

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> I wish to experiment with pic programming, my question is this:  What is
the cheapest flash pic(electrically erasable, and can be programmed multiple
times) and, where can I get it in small quanties?

16F628 (maybe 16F627, but the price difference is very small)

http://www.phanderson.com
http://www.digikey.com

Wouter van Ooijen

Van Ooijen Technische Informatica: http://www.voti.nl
Jal compiler for PIC uC's:  http://www.xs4all.nl/~wf/wouter/pic/jal

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'PIC & Pt100... Calibrate? (Resending)'
2002\08\15@020502 by iso-8859-1?q?Mohit=20Mahajan?=
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Hello,

I'm designing a PIC16F877 based temperature controller
(with LCD, keypad, optocoupler etc.). I'll be using a
Pt100 RTD as the sensor. Range is from 0C to 499.5C
with steps of 0.5C. I'd like to give the user an
option to calibrate the controller. How do I do this?
(I mean, how should the calibration be done?) Or am I
right in using a Pt100 as the sensor, which can let
the user calibrate the controller "on the fly"?

Thanks in advance,
Mohit.

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2002\08\15@022609 by Spehro Pefhany

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At 07:01 AM 8/15/02 +0100, you wrote:
>Hello,
>
>I'm designing a PIC16F877 based temperature controller
>(with LCD, keypad, optocoupler etc.). I'll be using a
>Pt100 RTD as the sensor. Range is from 0C to 499.5C
>with steps of 0.5C. I'd like to give the user an
>option to calibrate the controller. How do I do this?
>(I mean, how should the calibration be done?)

Assuming you really mean "calibrate the controller"
(not the system), what reference do you expect the
user to have in order to perform the calibration?
If s/he is expected to have the usual NIST-traceable
(or equivalent) resistance box, then you can calibrate
by storing zero offset and span adjustment numbers
in EEPROM. Is that what you mean? In that case, it's
relatively straightforward.

>  Or am I
>right in using a Pt100 as the sensor, which can let
>the user calibrate the controller "on the fly"?

Don't understand this at all, sorry. What difference
does the sensor type make?  Sure you could throw in
resistors with the controller, but why would they be
more stable than the resistors actually used in your
design? Or am I guessing wrong here??

Best regards,

Spehro Pefhany --"it's the network..."            "The Journey is the reward"
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2002\08\15@084908 by Francisco Ares

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I have once used some Pt100 sensors, and I remember that they are not
perfectly linear, so we used a non-linear amplifier found on some databook.

The calibration procedure involved the extreme temperatures and also a
mid point known temperature - we had to adjust 3 trimmers and repeat
many times the procedure.

Perhaps if you create a lookup table based on the Pt100 own table and do
a segmented linearization, you may just calibrate the extremes.

Francisco


Mohit Mahajan wrote:

{Quote hidden}

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