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'[PIC]: Some laptops do have serial ports'
2005\09\19@142125 by John J. McDonough

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I recently got a new T43.  My T21 was getting a little long in the tooth,
and I was needing to buy a rather expensive program pretty soon, so that
pushed my new laptop schedule up a bit since I didn't want to invest $1100
on the old laptop.  (Well, my original schedule was to retire the T21 over a
year ago, but with a new disk it was still doing the job, even if I did get
razzed about the old clunker on some consulting assignments.)

Anyway, like practically all the laptops out there, the T43 has no serial
port, so I was resigned to doing my PIC-EL work on the desktop.  Not the end
of the world, but inconvenient.

Since my accountant is on me to spend money, I went the long dollar for the
fancy dock (Dock III) as well.  The dock is bigger than it should be, but it
does have a serial port.  I sort of suspected, however, that is was simply a
USB derived serial port that wouldn't work with my PIC-EL (which is
basically a SERPIC clone).

Well, I *finally* got all the software moved over from the old laptop and
today I took a shot at programming a PIC through the serial port ... and the
damned thing worked.  I am one happy camper.  I do have an ICD-2 and a NoPPP
so it's not like the PIC-EL is my only PIC programmer, but I want to do the
Elmer experiments exactly as my students do, so it's really good news that
the T43's serial port is a real one.

Before you go running out to get a T43 be warned that this is the high
priced spread.  I insisted on the little eraser thing (I'm annoyed that I
still get a touch pad but at least I can turn the thing off), and I really
like the keyboard light.  Both of those seem to be IBM-only features.  IBM
does have cheaper/faster laptops that I think work with the Dock III, but
they are big and heavy which is not something I wanted since I lug the thing
around a lot.

But if you want a laptop to work with your serial programmer, there are
still alternatives.

--McD

2005\09\19@142753 by Maarten Hofman

face picon face
>
> But if you want a laptop to work with your serial programmer, there are
> still alternatives.

I did tests with the Dell Lattitude: these do have a serial port, but the voltage is not sufficient for a JDM programmer without its own power supply. I can also add that most MSI motherboards for desktops do provide enough power to the serial port, and JDM works fine on those. Is there a list somewhere where people keep track of this compatibility?

Greetings,
Maarten Hofman.

2005\09\19@144032 by John J. McDonough

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----- Original Message -----
From: "Maarten Hofman" <spam_OUTcashimorTakeThisOuTspamgmail.com>
Subject: Re: [PIC]: Some laptops do have serial ports


> I did tests with the Dell Lattitude: these do have a serial port, but the
> voltage is not sufficient for a JDM programmer without its own power
> supply.
> I can also add that most MSI motherboards for desktops do provide enough
> power to the serial port, and JDM works fine on those. Is there a list
> somewhere where people keep track of this compatibility?

A couple of years back before we did the PIC-EL I asked a few dozen people
to put a voltmeter on their serial ports, and almost none had enough there
to power a programmer.  The most common voltage was +/- 0.9 (!) volts.  Of
course, quite a few had more, and a very few had 12 (which I believe is the
specification), but 0.9 was the most common.  I suppose for most circuits,
you can detect + or - relatively easily as long as the voltage is above a
diode drop, so 0.9 just barely makes it.

--McD

2005\09\19@144351 by alan smith

picon face
I've got a Acer Aspire 1410....love the machine, use a USB/rs232  dongle....not a problem talking to about 10 different devices that I interface with, including picstarts.

Maarten Hofman <.....cashimorKILLspamspam@spam@gmail.com> wrote:>
> But if you want a laptop to work with your serial programmer, there are
> still alternatives.

I did tests with the Dell Lattitude: these do have a serial port, but the
voltage is not sufficient for a JDM programmer without its own power supply.
I can also add that most MSI motherboards for desktops do provide enough
power to the serial port, and JDM works fine on those. Is there a list
somewhere where people keep track of this compatibility?

Greetings,
Maarten Hofman.

2005\09\19@145108 by marcel

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My former employer, LinuxCertified, sells laptops, and almost all of them have
proper serial ports built in. They do your choice of linux (from a list of a
handful distributions) and optionally dual-boot at cost of windows.

http://linuxcertified.com/linux_laptops.html

- Marcel

"John J. McDonough" <mcdspamKILLspamis-sixsigma.com> wrote:

{Quote hidden}

2005\09\19@145108 by marcel

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My former employer, LinuxCertified, sells laptops, and almost all of them have
proper serial ports built in. They do your choice of linux (from a list of a
handful distributions) and optionally dual-boot at cost of windows.

http://linuxcertified.com/linux_laptops.html

- Marcel

"John J. McDonough" <.....mcdKILLspamspam.....is-sixsigma.com> wrote:

{Quote hidden}

2005\09\19@150134 by David Van Horn

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Acer Ferarri!  Paralell and serial :)



2005\09\19@151250 by Mchipguru

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I want big and fast with serial and parallel ports so I am looking at the alienware laptops. Lots of money and short battery life but 17" screen, P4 with hyperthreading , dual hard drives Raid 0, and both serial and parallel ports built in.
Larry
{Quote hidden}

> --

2005\09\19@172635 by William Chops Westfield

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On Sep 19, 2005, at 11:40 AM, John J. McDonough wrote:

>  The most common voltage was +/- 0.9 (!) volts.

I find  that difficult to believe.  Perhaps they were using "smart"
rs232 drivers that don't turn on till a cable is plugged it...

(rs232 spec is +/-3V, so it's easily possible to be in-spec and still
not have enough voltage to drive a JDM...)

BillW

2005\09\19@174130 by William Chops Westfield

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On Sep 19, 2005, at 2:26 PM, William Chops Westfield wrote:

>>  The most common voltage was +/- 0.9 (!) volts.
>
> I find  that difficult to believe.  Perhaps they were using "smart"
> rs232 drivers that don't turn on till a cable is plugged it...
>
On the other hand, if a laptop DOES have such a "smart" rs232 driver,
it's entirely possible that random homebuilt serial devices (like a
JDM) fail to provide the signal needed to EVER take it out of power-down
mode.  (a somewhat interesting possibility...)

BillW

2005\09\19@180107 by David Van Horn

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> On the other hand, if a laptop DOES have such a "smart" rs232 driver,
> it's entirely possible that random homebuilt serial devices (like a
> JDM) fail to provide the signal needed to EVER take it out of
power-down
> mode.  (a somewhat interesting possibility...)

Wouldn't it be powered up by some program opening the com port?




2005\09\19@181723 by William Chops Westfield

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On Sep 19, 2005, at 3:01 PM, David Van Horn wrote:

>> if a laptop DOES have such a "smart" rs232 driver, it's entirely
>> possible that homebuilt serial devices fail to provide the signal
>> needed to EVER take it out of power-down mode.

> Wouldn't it be powered up by some program opening the com port?
>
I don't know.  I never investigated this sort of rs232 driver in any
detail.  However, I think the idea was that the powerdown was
"automatic",
requiring no new intelligence from uart or software, so I don't see how
it would even NOTICE that someone had opened the com port (especially if
done in a non-traditional way...)

BillW

2005\09\19@182741 by William Chops Westfield

face picon face

On Sep 19, 2005, at 3:01 PM, David Van Horn wrote:

>
> Wouldn't it be powered up by some program opening the com port?

Maxim calls this feature "autoShutdown", and they describe is thusly:

{Quote hidden}

Sounds... incompatible with JDM?  JDM will require power from the
rs232 transmitters before ANY signals go back to the receivers, right?

BillW

2005\09\19@183838 by Bob Blick

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Some transceivers require power control, some do it automatically like the
MAX3233. Though I can't imagine any laptop maker using one, the pricing is
exorbitant. I suppose other chipmakes produce equivalents.

-Bob

{Quote hidden}

2005\09\19@201358 by Lee Jones

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>>  The most common voltage was +/- 0.9 (!) volts.

> I find  that difficult to believe.  Perhaps they were using "smart"
> rs232 drivers that don't turn on till a cable is plugged it...

> (rs232 spec is +/-3V, so it's easily possible to be in-spec and
> still not have enough voltage to drive a JDM...)

Actually, the EIA/TIA-232 spec says the transmiting end must
supply a signal of +5 to +15 volts or -5 to -15 volts.  The
receiving end must accept +3 to +25 volts or -3 to -25 volts.
A signal from -3 to +3 volts is in an undefined state.

Presumably, people were measuring the voltage at the output pin
so it should meet the open circuit transmitter side spec of below
-5 volts or above +5 volts with respect to local signal ground.

                                               Lee Jones

2005\09\19@205307 by David Van Horn

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The easy way to sense connection might be to sense the attachment of a
load.



2005\09\20@013249 by Chen Xiao Fan

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In most cases, it is cheaper to buy a USB to RS232 converter
and one Wisp628/EasyProg which works with most converters.
It is most likely cheaper as well to buy the ICD2 and a cheaper
Laptop. It is rather expensive to buy something like T43 to
work with a cheap JDM.

Of course IBM/Lenvo T43 must be a good laptop and you have
very good reason to buy it. But JDM is not a very good reason
for most people to buy the T43.

Regards,
Xiaofan

-----Original Message-----
From: John J. McDonough
Sent: Tuesday, September 20, 2005 2:21 AM
To: Microcontroller discussion list - Public.
Subject: [PIC]: Some laptops do have serial ports
...

But if you want a laptop to work with your serial programmer,
there are still alternatives.

--McD

2005\09\21@093316 by hugo

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part 0 26 bytes
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part 1 294 bytes content-type:text/plain; charset=ISO-8859-1 (decoded quoted-printable)

Couldn't this be solved by using a MAX232 or similar, looping the signal
through itself for a voltage boost?
Power would be taken from USB or PS/2 connectors (but then you could as
well use a Wisp628 anyway).

Attaching gif image of idea.

/Hugo


part 2 7704 bytes content-type:IMAGE/GIF; name="RS232Equalizer.gif" (decode)

part 3 35 bytes content-type:text/plain; charset="us-ascii"
 (decoded 7bit)

2005\09\21@095147 by Maarten Hofman

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>
> Couldn't this be solved by using a MAX232 or similar, looping the signal
> through itself for a voltage boost?
> Power would be taken from USB or PS/2 connectors (but then you could as
> well use a Wisp628 anyway).

Indeed... The big advantage of the JDM is that if you have a compliant
serial port it works very well, and it costs very little (I bought one
premade for $12.50). Adding parts would make it work on more serial ports,
but would make it more expensive, and therefore less attractive to those
people that DO have a proper serial port.
However, if the serial port doesn't provide enough voltage, it doesn't
work. This is very similar to the Wisp628, by the way: if the target circuit
doesn't supply enough voltage, it doesn't work either. However, usually it
is easier to fix the voltage of your target circuit than it is to fix the
voltage coming out of your serial port.
Greetings,
Maarten Hofman.

2005\09\21@100655 by Wouter van Ooijen

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> Couldn't this be solved by using a MAX232 or similar, looping
> the signal
> through itself for a voltage boost?
> Power would be taken from USB or PS/2 connectors (but then
> you could as
> well use a Wisp628 anyway).

You would loose the no-external-power appeal of the seial-port-powered
programmers. If you have power available you might (as you say) as 2well
use a propper programmer :)

Wouter van Ooijen

-- -------------------------------------------
Van Ooijen Technische Informatica: http://www.voti.nl
consultancy, development, PICmicro products
docent Hogeschool van Utrecht: http://www.voti.nl/hvu


2005\09\21@101129 by Wouter van Ooijen

face picon face
> This is very similar to the Wisp628, by the way: if the
> target circuit
> doesn't supply enough voltage, it doesn't work either.
> However, usually it
> is easier to fix the voltage of your target circuit than it
> is to fix the
> voltage coming out of your serial port.

You are also much morte likely to *know* the voltage your target circuit
is running on :)

Wouter van Ooijen

-- -------------------------------------------
Van Ooijen Technische Informatica: http://www.voti.nl
consultancy, development, PICmicro products
docent Hogeschool van Utrecht: http://www.voti.nl/hvu


2005\09\21@115217 by Byron A Jeff

face picon face
On Wed, Sep 21, 2005 at 04:06:56PM +0200, Wouter van Ooijen wrote:
> > Couldn't this be solved by using a MAX232 or similar, looping
> > the signal
> > through itself for a voltage boost?
> > Power would be taken from USB or PS/2 connectors (but then
> > you could as
> > well use a Wisp628 anyway).
>
> You would loose the no-external-power appeal of the seial-port-powered
> programmers. If you have power available you might (as you say) as 2well
> use a propper programmer :)

No real disagreement there. But the programmer issue is always something
that I see as a "chicken and egg" type problem. To get a "proper" programmer
you need a programmer, though it may be a temporary one.

So I believe there is value in a "no smarts" programmer, even if it's
only purpose is to serve as a code dumper to get to a smart programmer.

My Trivial programmers have served this purpose with parallel ports for
several years. However there is no doubt that parallel ports are a dying
breed, and pretty much dead on laptops. Serial will soon be completely
gone too in my estimation. USB has challenges because it has to be smart
to operate.

I see USB to serial cables as a potential stopgap, because they are smart
enough, and they are reasonably cheap. However I believe we've all seen
reports about the suspect drivers and modem signals not well synchronized
with the RX, TX signals. Both the WISP628 and the EasyProg only depend on a 3
wire RX/TX/GND connection to function. JDM needs a real serial port with
properly synchronized modem signals to function. There simply are not such
guarantees in the PC serial port market now.

So that's why I'm working on my Trivial Serial BootStrap Programmer. The
preliminary design page is here:

http://www.finitesite.com/d3jsys/tbs555

As built I can properly latch the PIC data with the PIC clock. However
The reverse RX channel isn't working yet. Also I'm now thinking that for
robustness it'll either need a MAX232 or use a transistor based level
shifter a la your El Cheapo that you used to use for WLoader.

It's not a "proper" programmer in the least. But it can server the purpose
of a code dumper when all you have is a serial port that honors RX and TX
only. And unfortunately I think we're going to see more and more of those
as time progresses.

BAJ

2005\09\21@125536 by Dwayne Reid

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At 09:52 AM 9/21/2005, Byron A Jeff wrote:

>So that's why I'm working on my Trivial Serial BootStrap Programmer. The
>preliminary design page is here:
>
>http://www.finitesite.com/d3jsys/tbs555

This is somewhat reminiscent of the simple programmer Tony Nixon
developed a few years back.  If I recall correctly, he encoded the
clock and data bits within ASCII characters.  I don't know if he
managed to achieve read-back, though.

I've got a copy somewhere but I think that there is an archive of
Tony's old site somewhere . . . can someone chime in with a URL?

dwayne

--
Dwayne Reid   <RemoveMEdwaynerTakeThisOuTspamplanet.eon.net>
Trinity Electronics Systems Ltd    Edmonton, AB, CANADA
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2005\09\21@140132 by Wouter van Ooijen

face picon face
> No real disagreement there. But the programmer issue is
> always something
> that I see as a "chicken and egg" type problem. To get a
> "proper" programmer
> you need a programmer, though it may be a temporary one.

For an intelligent programmer one will have to buy a PIC. If he buys it
from me he might as well pay the extra to have it programmed.

> So that's why I'm working on my Trivial Serial BootStrap
> Programmer. The
> preliminary design page is here:
> http://www.finitesite.com/d3jsys/tbs555

SBP OK, but not so T!


Wouter van Ooijen

-- -------------------------------------------
Van Ooijen Technische Informatica: http://www.voti.nl
consultancy, development, PICmicro products
docent Hogeschool van Utrecht: http://www.voti.nl/hvu


2005\09\21@155631 by Byron A Jeff

face picon face
On Wed, Sep 21, 2005 at 08:01:33PM +0200, Wouter van Ooijen wrote:
> > No real disagreement there. But the programmer issue is
> > always something
> > that I see as a "chicken and egg" type problem. To get a
> > "proper" programmer
> > you need a programmer, though it may be a temporary one.
>
> For an intelligent programmer one will have to buy a PIC. If he buys it
> from me he might as well pay the extra to have it programmed.

I haven't been able to convince those who want to program on the cheap
of that fact. I still have a steady support stream for the TLVP
parallel port programmer.

> > So that's why I'm working on my Trivial Serial BootStrap
> > Programmer. The
> > preliminary design page is here:
> > http://www.finitesite.com/d3jsys/tbs555
>
> SBP OK, but not so T!

It gets complicated when you try to do feedback through the RX pin. For
programming it's just two 555s configured in monostable mode.  So it's a 555,
a resistor, and a couple of caps each. The two pots are for tuning and can be
merged into the fixed resistors above them. The transistor connected to the
two 555 inputs makes the inputs edge triggered instead of level sensitive as
normal because the output of the right 555 going high forces the inputs high
again. So each 555 triggers for a fixed amount of time from the start bit
coming in from TX. The left 555 is tuned to reset about halfway through the
character cell while the right one is tuned to timeout somewhere around the
stop bit. So the PIC will latch the data on the falling edge of the left 555
and the right one guarantees only a single transistion per cell. It's
a similar idea to your ZPL bootloader where the length of each character
cell determines the bit transmitted.

But as I said the complication occurs with trying to get feedback through
the RX pin. The diode to the far right keeps the RX line idle when nothing
is transmitted via TX. It doesn't conduct for the full duration of the right
555 being active and so can be wiggled by the other transistors.

The transistor next to it is supposed to force a proper start bit. But I think
I have an error in my thinking. Note that RX and TX are running at nominal
PC RS-232 levels (0V -> 1 bit and 5V -> 0 bit). When that far diode pulls the
RX line to 0V, it transmits an idle line. When the 555 output that connects to
that diode goes high, the diode stops conducting and the line is suppose to
be pulled high transmitting a series of 0 bits. But the transistor connected
to the left 555 output acts as an inverter. The start bit causes the 555 output
to go high, causing that transistor to pull RX to 0V (or thereabouts). So instead
of RX going from 0V to 5V causing a start bit, it remains low staying idle. So
I believe I need to replace that transistor and its resistor with a diode so that
the diode conducts normally by releases just like the other diode when TX sends
a start bit. Let's presume that's the case for the rest of the discussion.
So until the left 555 times out, both diodes will be off and the RX line pulls
to 5V.

That leaves the final transistor connected to RX. Its input is controlled by
two sources: The incoming TX line and the Pic Data line.  I think there may
be problems here too. The TX line is guaranteed to generate a start bit. The
transistor to the far left (connected to TX) will turn on for the duration of
that start bit guaranteeing that the base of the transistor tied to the RX
line will be off. However presuming that a 0xff byte is transmitted for a read
of the bit, after the start bit that transistor to the left turns off and the
transistor connected to RX's base is coupled to +5 via a pullup turning that
transistor on. Without the PIC Data line being driven, RX should follow TX.
The problem is the PIC Data line. According the Figure 7.4 of the 16F8X
programmin specification, the PIC Data line is active for the entire time it's
transmitting bits. So that means that it's active during the time that I'm
trying to form a proper start bit and I cannot know what the value is going to
be. That means that the left transistor connected to TX in the lower left must
have override capability over the PIC data line. I also see now that the output
of the left 555 has no function in terms of RX and should be removed along with
its associated diode from above.

So I see myself as being stuck now unless I can figure out some steering diodes
in this game. TX needs to be able to drive the Pic Data line when necessary and
to allow for the PIC data line to drive RX when it's an output. However, I also
need to be able to override that Pic Data line output for a TX start bit. So
would two diodes going in and out of Pic Data separate the incoming TX data from
the outgoing Pic Data?

So Wouter you were definitely right, it's a bit compilicated to get RX to work right.

BAJ

2005\09\21@161112 by Bob Blick

face picon face
> ...it's a bit compilicated to get RX to
> work right.

But is this is just used for bootstrapping, is it really neccessary to
have read-back?

If you load it with "blink an LED" and it blinks when you take away Vpp,
that is a really good sign, then you load in a serial bootloader, flip a
switch and use it as a bootloader cable.

Cheerful regards,

Bob

2005\09\21@162131 by Dwayne Reid

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face
part 1 5664 bytes content-type:text/plain; charset="us-ascii"; format=flowedFurther to my last message:

Tony Nixon wrote:

ASCII PROGRAMMER

You may not have much of a need for this type of programmer, but it
is certainly different. It is simple to build and you don't need any
special software to program a PIC 16F84 chip. The idea behind this
project is to provide some means of loading a program into a PIC that
will then be able to program other PICs in a more conventional way.

This is a mouthful, but ...

How do you program a PIC to be a programming device without a
programmer, and why would you want to build a programmer if you
already have one that can program the PIC to be a programmer.

The answer here is to try to build a very cheap circuit that is easy
to build and does not need any special software to do the job. That
way, after it has done it's job, the parts can end up back into the
junk box. The simplest approach I could come up with, was to use a
simple circuit, the PC Serial Port and be able to program a PIC just
by sending (2) different ASCII codes. This way, you do not need any
special software to set up, and the circuit can be built out of junk
bits and pieces. This programmer is not capable of reading data from
a PIC, but for the purpose it is meant for, that doesn't matter.

Two things we need to extract out of the serial data are :-

(1) Clock pulses
(2) Data bits

While programming, new data bits entering the PIC are placed on pin
RB7 while the clock pulse appearing on pin RB6 is in a high state.
The PIC will accept the new data when the clock line is brought low.
Programming comands are 6 bits long, and the data that follows
consists of a Low Start Bit plus 14 data bits that the PIC will store
in memory and then a Low Stop Bit. The circuit shown below extracts
clock pulses and data bits from the data stream produced by sending
the (2) ASCII codes from the serial port.
The ASCII characters that produce this data are :-

 #0

 Null Character
 #127
 DEL Character

Circuit Diagram

The circuit is very simple and is also easy to construct. ASCII data
comes on the Tx line from the PC serial port on Pin 3 of a DB9
connector. This data is shown in MAGENTA and can be around 11 volts
above and below ground. This is damaging to a circuit that is
designed to run on 5 volts, so R1 and Z1 reduce the positive voltage
to 5 volts and the negative voltage is blocked by D1.

Next the data bits that the PIC will store are extracted from the
ASCII value. The circuit path for this is in TEAL.

Now the tricky part...

The IC used in the circuit is a Schmitt Trigger Quad NAND gate. U1a
is configured as a monostable multivibrator. When the incoming signal
goes from 0V to 5V, capacitor C1 charges via R3. This has the effect
of producing a very short +ve pulse at U1a pin 2. U1a pin 1 is tied
to the 5 volt rail so the output of this gate, pin 3, goes low for a
brief period and then it goes high again. When the output from this
gate goes high, the next monostable, U1b, is trigerred in the same
way. The difference here is that the time period is slightly longer.
The 47k resistor is greater than the 15k resistor. This produces the
pulse that is used to clock the data into the PIC. Unfortunately, it
is upside down at this point, so U1c is used to invert the signal
which is now at the BLUE part of the circuit. Diodes D2 and D3
provide quick discharge paths for the capacitors.

The chart below shows the wave forms generated by the circuit. The
colours correspond to the circuit paths shown above.

You can see by the data here that as the RB6 clock pin is brought
low, the data is already valid on the RB7 data pin. The data that
would be clocked in from this chart is 1010.

To get these wave forms, the serial port is set to 1200 baud, 7 data
bits, no parity, and 1 stop bit. The data above will be generated if
these characters are sent...

 #0 - NULL
 #127 - DEL

 #0 - NULL
 #127 - DEL

 Data Bit = 1
 Data Bit = 0
 Data Bit = 1
 Data Bit = 0

These following character strings will program this instruction into
the PIC at the current ROM address. All of the data is sent to the
PIC with the LSB first. You will notice that we need to send one
ASCII character for each data bit.

 3014

 MOVLW 14h

First we send the Load Data Command - 2h. This data is sent as 6 bits
of information - 000010.

#127, #0, #127, #127, #127, #127

Now we send the ROM data. This consists of a Logic 0 Start Bit,
followed by 14 bits of data, then a Logic 0 Stop Bit.

 Start  4  1  0
 3

 Stop
#127, #127, #127, #0, #127, #0, #127, #127, #127, #127, #127, #127,
#127, #0, #0, #127

To get the PIC to program that location, we use the Begin Programming
Command - 8h. This data is sent as 6 bits of information - 001000.

#127, #127, #127, #0, #127, #127

This will be a very tedious task if your program is fairly large. One
way around this could be to write a program in BASIC that will do the
hard work for you. That will involve getting the HEX data from a
compiled file and then converting each 1 bit to ASCII #0 and each 0
bit to ASCII #127 for each of the words that need to be programmed.
Combine each of the ASCII values into a 'string' and then send it to
the serial port.

One thing I haven't mentioned yet is the Vpp or Programming voltage.
This needs to be around 13 Volts and it can be simply connected to
the MCLR pin with a small switch. If the programmed PIC is to be used
as a programmer, then that voltage and a 5 Volt supply is probably
already available.

Here is a pretty messy bread boarded circuit, but it works ok.

This is a PCB design for the programmer, if you would like to build
one this way.


part 2 5620 bytes content-type:image/gif; name="prgpcb00.gif"; (decode)

part 3 5099 bytes content-type:image/gif; name="progcct0.gif"; (decode)

part 4 7941 bytes content-type:image/gif; name="progchr0.gif"; (decode)

part 5 519 bytes content-type:text/plain; charset="us-ascii"; format=flowed (decode)

part 6 35 bytes content-type:text/plain; charset="us-ascii" (decode)

2005\09\21@171058 by Wouter van Ooijen

face picon face
> The circuit is very simple and is also easy to construct.

That might be true, but the more important question is: is it reliably?
If 1k people build it, how many of their products will fail, and how
easy will it be for them to correct their mistakes? Monostables
(especially when built from gates!) are not my idea of high
reliability/reproduceability.

Just in case you think you have invented something new: I think I have
seen this method to drive a shift register so one PIC pin could drive an
HD44780 LCD.

Now for something completely different: I think I have a realy original
idea (about reading a matrix keyboard with very few pins). I have
browsed a patent database and found some 20 patents in roughly the same
area, but nothing like my idea. What would be the next step to prove to
myself that it has been cooked up before, in other words: which other
reservoirs of knowledge should I check?

Wouter van Ooijen

-- -------------------------------------------
Van Ooijen Technische Informatica: http://www.voti.nl
consultancy, development, PICmicro products
docent Hogeschool van Utrecht: http://www.voti.nl/hvu


2005\09\21@171102 by Wouter van Ooijen

face picon face
> So Wouter you were definitely right, it's a bit compilicated
> to get RX to work right.

A write-only programmer might fill some need, but it would need to be
absolutely idiot-proof (which is probably impossible, given the level of
idiotness avaiable), or I am afraid you would be overwhelmed with
incomprehensible reports about non-working proggers. Maybe you should
make it available anonymously :)

Wouter van Ooijen

-- -------------------------------------------
Van Ooijen Technische Informatica: http://www.voti.nl
consultancy, development, PICmicro products
docent Hogeschool van Utrecht: http://www.voti.nl/hvu



2005\09\21@181939 by Byron A Jeff

face picon face
On Wed, Sep 21, 2005 at 01:11:11PM -0700, Bob Blick wrote:
> > ...it's a bit compilicated to get RX to
> > work right.
>
> But is this is just used for bootstrapping, is it really neccessary to
> have read-back?

I don't think so. But IIRC the last time I had an online discussion about
this project, some folks were asking for verification. I know why...

> If you load it with "blink an LED" and it blinks when you take away Vpp,
> that is a really good sign, then you load in a serial bootloader, flip a
> switch and use it as a bootloader cable.

Agreed. KISS. BTW they wanted verification so that they could use it as
a traditional programmer.

Maybe I shouldn't listen so well the next time. Thanks for the suggestion.

BAJ

2005\09\21@221017 by Chen Xiao Fan

face
flavicon
face
Most of laptops nowadays do have USB ports. ;-)

Probably USB based programmer is the way to go. Wisp628
is great. A USB based Wisp628 (Wisp2550?) and EasyProg
(EasyProg Pro?) will be even greater!

GTP-USB/WinPIC800 is one such programmer (freeware but
closed source). It supports lot of PICs and dsPICs.
http://perso.wanadoo.es/siscobf/winpic800.htm (Spanish)
http://forum.microchip.com/tm.asp?m=108574 (uChip Forum post)

PICkit 2 (US$35) is another promising USB based programmer.

The following is from the post to pickit-devel by Dan Butler
"the keeper of the PICkit" from Microchip.

It is good to know that PICkit 2 will support more 16F parts and
18F parts within this year and even dsPIC support is on the
pipeline. It is also great that he is very supportive of a Linux
version of the PICkit 2 host application.

Regards,
Xiaofan

{Original Message removed}

2005\09\21@223408 by Chen Xiao Fan

face
flavicon
face
I guess you have checked the biggest reservoirs: the Internet.
Have you checked PIClist.com aka the biggest reservoirs for PIC
outside Microchip? ;)-

The university libraries can also be a good resource.

Then talk to a patent lawyer. Even if there are some similar prior
arts, probably they can still make black to white and vice versa.
They are talking in some foreign-to-mankind language so that
nobody will understand them. Then you can claim as much as possible,
even blinking an LED using a PIC pin with some special features. ;-)

Regards,
Xiaofan

{Original Message removed}

2005\09\22@015133 by Wouter van Ooijen

face picon face
> I guess you have checked the biggest reservoirs: the Internet.

of course. the challenge is to find good keywords.

> Have you checked PIClist.com aka the biggest reservoirs for PIC
> outside Microchip? ;)-

of course :)

> Then talk to a patent lawyer.

I did, my father-in-law is a (retired) patent lawyer.

Wouter van Ooijen

-- -------------------------------------------
Van Ooijen Technische Informatica: http://www.voti.nl
consultancy, development, PICmicro products
docent Hogeschool van Utrecht: http://www.voti.nl/hvu


2005\09\22@130627 by Howard Winter

face
flavicon
picon face
Wouter,

On Wed, 21 Sep 2005 23:10:59 +0200, Wouter van Ooijen wrote:

>...<
> Now for something completely different: I think I have a realy original
> idea (about reading a matrix keyboard with very few pins). I have
> browsed a patent database and found some 20 patents in roughly the same
> area, but nothing like my idea. What would be the next step to prove to
> myself that it has been cooked up before, in other words: which other
> reservoirs of knowledge should I check?

Sadly, the thing that would be useful - telling us all on here about it - would prevent you getting a patent
under European law.  Otherwise we could all tell you what an excellent idea it is and/or how we all already
thought of it at primary school...   :-)

If you've looked everywhere you can think of, the next step is to file the initial patent application (in the
UK that doesn't cost much)  which gives you time to do more research, while "keeping your place", before you
go for the whole thing.

Cheers,


Howard Winter
St.Albans, England


2005\09\22@132657 by Mark Rages

face picon face
On 9/21/05, Wouter van Ooijen <spamBeGonewouterspamBeGonespamvoti.nl> wrote:
>
> Now for something completely different: I think I have a realy original
> idea (about reading a matrix keyboard with very few pins). I have
> browsed a patent database and found some 20 patents in roughly the same
> area, but nothing like my idea. What would be the next step to prove to
> myself that it has been cooked up before, in other words: which other
> reservoirs of knowledge should I check?
>

"PICkit 1 Tips'n'Tricks" #7:

http://ww1.microchip.com/downloads/en/DeviceDoc/40040b.pdf

Regards,
Mark
markrages@gmail
--
You think that it is a secret, but it never has been one.
 - fortune cookie

2005\09\22@134739 by Wouter van Ooijen

face picon face
> > Now for something completely different: I think I have a
> realy original
> > idea (about reading a matrix keyboard with very few pins).

> "PICkit 1 Tips'n'Tricks" #7:
> http://ww1.microchip.com/downloads/en/DeviceDoc/40040b.pdf

I did not know about that one, and I did not see it in any of the
patents I checked either. But it is not the idea I have.

Note that trick #7 is not a complete description: no optimal resistor
values, no formula to derive these values, no analysis of the required
accuracy of the resistors (both for various matrix sizes). If it can be
done with 1% it would be usefull, if it requires 0.1% it might not be
cost-effective, if it requires better than 0.1% it is probably
infeasible.

Wouter van Ooijen

-- -------------------------------------------
Van Ooijen Technische Informatica: http://www.voti.nl
consultancy, development, PICmicro products
docent Hogeschool van Utrecht: http://www.voti.nl/hvu


2005\09\22@142249 by Bob Blick

face picon face
> Note that trick #7 is not a complete description: no optimal resistor
> values, no formula to derive these values, no analysis of the required
> accuracy of the resistors (both for various matrix sizes). If it can be
> done with 1% it would be usefull, if it requires 0.1% it might not be
> cost-effective, if it requires better than 0.1% it is probably
> infeasible.

Not to mention switch contact resistance. Using that method for more than
4 switches is asking for trouble.

-Bob


2005\09\22@143144 by Mark Rages

face picon face
On 9/22/05, Bob Blick <TakeThisOuTbblickEraseMEspamspam_OUTsonic.net> wrote:
> > Note that trick #7 is not a complete description: no optimal resistor
> > values, no formula to derive these values, no analysis of the required
> > accuracy of the resistors (both for various matrix sizes). If it can be
> > done with 1% it would be usefull, if it requires 0.1% it might not be
> > cost-effective, if it requires better than 0.1% it is probably
> > infeasible.
>
> Not to mention switch contact resistance. Using that method for more than
> 4 switches is asking for trouble.
>
> -Bob
>

Somebody at Ford decided to use that method for the cruise control
switches in my steering wheel.

Nineteen years later, the sliding contacts in the steering column are
adding some resistance of their own.

It's unsettling to press "cancel" and feel the car accelerate.

Regards,
Mark
markrages@gmail
--
You think that it is a secret, but it never has been one.
 - fortune cookie

2005\09\23@040031 by Alan B. Pearce

face picon face
>> Not to mention switch contact resistance. Using that
>> method for more than 4 switches is asking for trouble.
>
>Somebody at Ford decided to use that method for the
>cruise control switches in my steering wheel.
>
>Nineteen years later, the sliding contacts in the steering
>column are adding some resistance of their own.
>
>It's unsettling to press "cancel" and feel the car accelerate.

Isn't this what is known as "planned obsolescence?

2005\09\23@054920 by Michael Rigby-Jones

picon face


{Quote hidden}

How about this one?

http://www.mikerj.clara.net/keypad.html

Regards

Mike

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2005\09\23@061018 by Wouter van Ooijen

face picon face
[reading a keypad with less I/O pins]

> How about this one?
> http://www.mikerj.clara.net/keypad.html

Nice! (but not like my idea)

I should make a webpage about such ideas. But no, Wisp648 first :)

Wouter van Ooijen

-- -------------------------------------------
Van Ooijen Technische Informatica: http://www.voti.nl
consultancy, development, PICmicro products
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