Searching \ for 'Pens for Writing OSCCAL Values on JW Parts' in subject line. ()
Make payments with PayPal - it's fast, free and secure! Help us get a faster server
FAQ page: www.piclist.com/techref/index.htm?key=pens+writing+osccal
Search entire site for: 'Pens for Writing OSCCAL Values on JW Parts'.

Truncated match.
PICList Thread
'Pens for Writing OSCCAL Values on JW Parts'
1998\12\19@004742 by Michael J. Ghormley

flavicon
face
I have received a couple of private E-mails asking for particulars after
mentioning this pen.  So I am thinking maybe more people would like to know
more about this.

I have been writing the factory OSCCAL value read from windowed 12C509/JW's
onto the bottom of the chips.  I have been using the Speedball "Painters"
Metalic Marker to do this.  It is a fine-point pen that writes in paint
rather than ink.  I use the gold color (#7328).  I find them in craft and
stationery stores for ~$3US.

It takes a steady hand, but is very readable and pretty permanent --
especially being protected by the chip's pins.

Michael

*************************************************************************
When the way of the Tao is forgotten, kindness and ethics must be taught.
Men must learn to pretend to be wise and good.  --  Lao Tzu
*************************************************************************

1998\12\19@091929 by wwl

picon face
On Sat, 19 Dec 1998 09:36:43 -0800, you wrote:

>I have received a couple of private E-mails asking for particulars after
>mentioning this pen.  So I am thinking maybe more people would like to know
>more about this.
>
>I have been writing the factory OSCCAL value read from windowed 12C509/JW's
>onto the bottom of the chips.  I have been using the Speedball "Painters"
>Metalic Marker to do this.  It is a fine-point pen that writes in paint
>rather than ink.  I use the gold color (#7328).  I find them in craft and
>stationery stores for ~$3US.
>
>It takes a steady hand, but is very readable and pretty permanent --
>especially being protected by the chip's pins.
Remember that pencils write pretty well on ceramic!

1998\12\19@100233 by Michael J. Ghormley

flavicon
face
Mike Harrison wrote:

> Remember that pencils write pretty well on ceramic!

And rub off just as well!  The chips that I have are pretty dark on the
bottom and you would have to rely on the reflectivness of the graphite to
read it, methinks.

IMO this number is too important to not use some more permanent means of
saving it.  Either my idea or the Staedtler-Mars Lumocolor #313 suggested
by Lawrence Lyle and others is the way to go.  The pins of the DIP
packages will give you protection from the occasional finger, but I would
worry that placing it in conductive foam a few times might rub it off.

Of course, your mileage may vary.

Michael

*************************************************************************When th
e way of the Tao is forgotten, kindness and ethics must be taught.
Men must learn to pretend to be wise and good.  --  Lao Tzu
*************************************************************************

1998\12\19@110103 by Reginald Neale

flavicon
face
>Mike Harrison wrote:
>
>> Remember that pencils write pretty well on ceramic!
>
>And rub off just as well!  The chips that I have are pretty dark on the
>bottom and you would have to rely on the reflectivness of the graphite to
>read it, methinks.
>
>IMO this number is too important to not use some more permanent means of
>saving it.  Either my idea or the Staedtler-Mars Lumocolor #313 suggested
>by Lawrence Lyle and others is the way to go.  The pins of the DIP
>packages will give you protection from the occasional finger, but I would
>worry that placing it in conductive foam a few times might rub it off.
>
>Of course, your mileage may vary.

The Sanford 'Sharpie' is a permanent-ink marker pen that's available in a
fine-point version. You can get it at Office Max or Staples.

Reg Neale

1998\12\20@111804 by Peter L. Peres

picon face
On Sat, 19 Dec 1998, Mike Harrison wrote:

> Remember that pencils write pretty well on ceramic!

Yes ! That is a golden idea. I suppose that one can help a little with
diamond paper before writing. Graphite withstands most washing and spray
liquids, but not rubbing.

I was thinking along the lines of a capilar dunked in HF + indicator (red)
to write with on ceramic and glass packages. The HF will etch and the
indicator will remain in the etched out area, hopefully. I think that
someone is selling glass markers that work along the same lines (perhaps
not HF). I'll ask the chemist this week.

Beware: HF is an evil substance. Observe precautions when using.

I'd like to thank everyone who has contributed to this thread so far, I've
actually tried out quite a few 'permanent' markers, with the result, that
the alcohool and other undetermined solvents in a certain laquer that I
apply after assembly gets at the writing even underneath, turning it into
illegible splotches of ink.

My method of scratching the numbers into the brass bezel with a steel
needle was the best imho, until the pencil idea that is.

Actually imho Microchip could save us the labor by programming the
packaging inscriptor machine to put the relevant constant at the end of
the serial number f.ex. imho

Peter

1998\12\20@234316 by Shahid Sheikh

picon face
Since so many people have replied to this, I thought I do so as well and
add to the noise. I just write it on a sticker with a fine tip pen and
stick it to the underside of the chip.

Shahid

1998\12\21@145133 by John Payson

flavicon
face
|I have been writing the factory OSCCAL value read from windowed 12C509/JW's
|onto the bottom of the chips.  I have been using the Speedball "Painters"
|Metalic Marker to do this.  It is a fine-point pen that writes in paint
|rather than ink.  I use the gold color (#7328).  I find them in craft and
|stationery stores for ~$3US.

What about having a programmer automatically determine the best
value to use whenever an EPROM device is programmed.  It would
only cost 7 words of code space from $1F8 to $1FE or $3F8 to
$3FE to burn the test program, and it would then eliminate the
need to worry about the calibration constant.  I've posted this
idea before but not had time to implement it.  Has anyone else
tried it?

1998\12\21@202354 by Jim Robertson

flavicon
face
At 13:52 21/12/98 -0600, you wrote:
>|I have been writing the factory OSCCAL value read from windowed 12C509/JW's
>|onto the bottom of the chips.  I have been using the Speedball "Painters"
>|Metalic Marker to do this.  It is a fine-point pen that writes in paint
>|rather than ink.  I use the gold color (#7328).  I find them in craft and
>|stationery stores for ~$3US.
>
>What about having a programmer automatically determine the best
>value to use whenever an EPROM device is programmed.  It would
>only cost 7 words of code space from $1F8 to $1FE or $3F8 to
>$3FE to burn the test program, and it would then eliminate the
>need to worry about the calibration constant.  I've posted this
>idea before but not had time to implement it.  Has anyone else
>tried it?


This is how I solve the OSCCAL problem.

1) Scratch each part with a unique, sequentual letter, A, B, C
2) The part is now  "virtual" with the name of 12C508__A, 12C508__B etc.
3) Put it in my programmer.
4) Click on the "CAL"  button
5) Click on the "AVAILABLE" radio button (Up to 10 or 12 devices supported)
6) Click on the "READ CAL" button. CAL is now read.
7) Click on "SAVE CAL and EXIT" CAL is now written to file.
8) Use virtual parts in sequence A, B, C -OR-  in reverse order.
9) Mark any gaps in sequence as "unavailable." Nice feature.
10) Use "AUTO CAL" and let my programmer insert CAL Automatically everytime!
11) Save my sweat for code writing and not trivial stuff.
12) Wonder why more people don't use my WinTM4 software.

Jim



--------------------------------------------------------
Jim Robertson
Email: spam_OUTnewfoundTakeThisOuTspampipeline.com.au

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

1998\12\21@220618 by James Cameron

flavicon
face
Jim Robertson wrote:
> 12) Wonder why more people don't use my WinTM4 software.

Does it run on Linux?  ;-)
No?  Oh, that'd be why I don't use it then.

I've found some programming code uses the PC system clock for timing.  A
call to wait for one hundred microseconds may end up waiting for between
101 and 200 microseconds.   Certain addresses will have been given a
pulse that is longer than what the programming specification calls for.

Does anybody know what impact this may have on programming the 12C509-JW
parts?

--
James Cameron                                      (.....cameronKILLspamspam@spam@stl.dec.com)

OpenVMS, Linux, Firewalls, Software Engineering, CGI, HTTP, X, C, FORTH,
COBOL, BASIC, DCL, csh, bash, ksh, sh, Electronics, Microcontrollers,
Disability Engineering, Netrek, Bicycles, Pedant, Farming, Home Control,
Remote Area Power, Greek Scholar, Tenor Vocalist, Church Sound, Husband.

"Specialisation is for insects." -- Robert Heinlein.

1998\12\22@163231 by Peter L. Peres

picon face
On Tue, 22 Dec 1998, James Cameron wrote:

> Does anybody know what impact this may have on programming the 12C509-JW
> parts?

No, but I know from experience that it has none on several 16C54JWs and a
small score of 16C54XT-04 OTPs.

There is no warranty of course, but the spec sheet gives a range between
10 and 1000 usec for the programming pulse for normal locations and
between 1000 and 10,000 for the fuses on the '54 ?

Please check these numbers, they are off of my head now.

I'd like to add that I wrote a programmer driver that tabulated the no. of
pulses required to program each location and the number was invariably of
4 for all locations, even after several tens of erasures on the JW parts,
for 100 usec pulses. This is from the time when the programming specs
specified 3 x over-programming.

Peter

1998\12\22@171127 by Peter L. Peres

picon face
On Mon, 21 Dec 1998, John Payson wrote:

> What about having a programmer automatically determine the best
> value to use whenever an EPROM device is programmed.  It would
> only cost 7 words of code space from $1F8 to $1FE or $3F8 to
> $3FE to burn the test program, and it would then eliminate the
> need to worry about the calibration constant.  I've posted this
> idea before but not had time to implement it.  Has anyone else
> tried it?

I haven't and I'm interested. Could you explain a little bit ? Does the
programmer have to be able to turn on the chip in normal operation mode
and read out a pin ?

Peter

1998\12\23@163532 by John Payson

flavicon
face
> What about having a programmer automatically determine the best
> value to use whenever an EPROM device is programmed.  It would
> only cost 7 words of code space from $1F8 to $1FE or $3F8 to
> $3FE to burn the test program, and it would then eliminate the
> need to worry about the calibration constant.  I've posted this
> idea before but not had time to implement it.  Has anyone else
> tried it?

|I haven't and I'm interested. Could you explain a little bit ? Does the
|programmer have to be able to turn on the chip in normal operation mode
|and read out a pin ?

You'd need to be able to start/run the PIC normally.  Note that
since you'd be testing the calibration before burning the fuse
to disable /MClr, you could use /MClr L->VPP to re-enter program
mode.

The code I'd recommend using would be this [at $1F9 or $3F9]

               movlw   127
               xorlw   255
               movwf   5
               movlw   254             ; Bit 0 is only output
               tris    PORTB
               comf    PORTB

Running this code will cause the PORTB.0 pin to flip every 512
or 1024 cycles.  Start with the code as above, and the modify it
per the following algorithm:

               if oscillator was too fast, blow bit 7 of the xorlw
               blow bit 6 of the first movlw instruction
               if oscillator was too fast, blow bit 6 of the xorlw
               blow bit 5 of the first movlw instruction
               if oscillator was too fast, blow bit 5 of the xorlw
               blow bit 4 of the first movlw instruction
               if oscillator was too fast, blow bit 4 of the xorlw

; Note that for the original '508's you may stop here.  If you
; want to allow for an 8-bit calibration constant, you may keep
; going...

               blow bit 3 of the first movlw instruction
               if oscillator was too fast, blow bit 3 of the xorlw
               blow bit 2 of the first movlw instruction
               if oscillator was too fast, blow bit 2 of the xorlw
               blow bit 1 of the first movlw instruction
               if oscillator was too fast, blow bit 1 of the xorlw
               blow bit 0 of the first movlw instruction
               if oscillator was too fast, blow bit 0 of the xorlw

Once that's accomplished, determine which of the last two speeds
was the best; use that speed as the calibration value.

Cute, eh?

1998\12\24@120448 by Peter L. Peres

picon face
On Wed, 23 Dec 1998, John Payson wrote:

> Cute, eh?

Yes ! Nice. imho it would be nice if Mchip could pre-program 508's and
509s with a simple program that toggles an IO bit like this when the
device is virgin (OTPs). Then the programmer could determine the real
frequency for each device before burning the code, and could call a
patcher that adjusts code loops in the object file to adjust for the exact
real speed, instead of trimming the oscillator. Ah, I'm just dreaming ;)

Alternatively, have a FLASH location hold the trim value and allow the PIC
to correct itself at run-time in a test jig using users' software, after
burning. This obviates the need for factory-inserted trim values (a
missing inverter in Silicon can make the 0xFF factory line FLASH trim
location a 0x80 for a sane start value). Ah, I'm just dreaming some more
;) ;)

Peter

More... (looser matching)
- Last day of these posts
- In 1998 , 1999 only
- Today
- New search...