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PICList Thread
'frying a PIC'
1997\08\13@131410 by unknown667

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For some reason I'm unable to erase my PIC16C74A.  I've got a Datarase II 4
chip UV eraser, which has been working fine, and the Microchip umm...
quickstart or something programmer.  Suddenly, today, I find that when the
chips come out of the eraser, the programming software I'm using
(MPS16C.EXE) reports that the chip is not blank.  Any ideas on how I could
have fried the chips?

---
Unknown

1997\08\13@132524 by Andy Kunz

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face
At 09:51 AM 9/10/97 -0700, you wrote:
>For some reason I'm unable to erase my PIC16C74A.  I've got a Datarase II 4

Did you happen to code protect the thing?  If so, it'll take some time
under a light - I do about 2 hours in a Database II to clear them.

Some chips never erase - I have a '622 with 48+ hours and it's still
clogged up.  GOing to play with it under an x-ray or something.

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\08\13@135633 by Shane Nelson

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On Wed, 13 Aug 1997, Andy Kunz wrote:

> At 09:51 AM 9/10/97 -0700, you wrote:
> >For some reason I'm unable to erase my PIC16C74A.  I've got a Datarase II 4
>
> Some chips never erase - I have a '622 with 48+ hours and it's still
> clogged up.  GOing to play with it under an x-ray or something.
>
> Andy
>

I have a dozen 'c54 chips that won't erase. I'm thinking I probably fried
them with too much current...

1997\08\13@141046 by unknown667

picon face
At 11:56 AM 8/13/97 -0600, Shane Nelson wrote:
>> Some chips never erase - I have a '622 with 48+ hours and it's still
>> clogged up.  GOing to play with it under an x-ray or something.
>I have a dozen 'c54 chips that won't erase. I'm thinking I probably fried
>them with too much current...

What programmer/eraser were you using?

---
Unknown

1997\08\13@145108 by Shane Nelson

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face
On Wed, 10 Sep 1997, unknown667 wrote:

> At 11:56 AM 8/13/97 -0600, Shane Nelson wrote:
> >> Some chips never erase - I have a '622 with 48+ hours and it's still
> >> clogged up.  GOing to play with it under an x-ray or something.
> >I have a dozen 'c54 chips that won't erase. I'm thinking I probably fried
> >them with too much current...
>
> What programmer/eraser were you using?
>

Picstart Plus Development Programmer, and a Logical Devices, inc UV
Eraser.

-Shane.

1997\08\13@152007 by Martin R. Green

picon face
You might not have fried them after all.  I have heard that one of the ways
MicroChip increased the security of their devices is to increase the UV
exposure needed to erase the configuration bits.  This is because some
enterprising souls figured out how to manipulate the chip voltage and
erasure techniques to clear the code protect bit while still leaving the
code itself intact.  By making the configuration bits much harder to erase,
the contents of the program memory will be gone by the time the protect bit
is cleared.

Anyway, it could be that you just need to increase your erase time over
what you had been using, since your programmer might report that device is
not blank even if only the configuration byte is non-blank.

If you are using old (pre-used) chips that you KNOW don't have the new
security features, your chips might still be OK.  UV light sources weaken
with age, and it is possible that all you need to do is increase the erase
duration to compensate.  If you find it take a lot longer to erase chips
now, you might want to replace your UV tube.

Finally, check for dirty quartz windows on the chips themselves, and maybe
(this one is a stretch) the chips are just getting harder to erase with
age.


CIAO - Martin R. Green
spam_OUTelimarTakeThisOuTspambigfoot.com

----------
From:   unknown667[SMTP:.....unknown667KILLspamspam@spam@HOTMAIL.COM]
Sent:   Wednesday, September 10, 1997 12:51 PM
To:     PICLISTspamKILLspammitvma.mit.edu
Subject:        frying a PIC

For some reason I'm unable to erase my PIC16C74A.  I've got a Datarase II 4
chip UV eraser, which has been working fine, and the Microchip umm...
quickstart or something programmer.  Suddenly, today, I find that when the
chips come out of the eraser, the programming software I'm using
(MPS16C.EXE) reports that the chip is not blank.  Any ideas on how I could
have fried the chips?

---
Unknown

1997\08\13@152145 by Andy Kunz

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face
>I have a dozen 'c54 chips that won't erase. I'm thinking I probably fried
>them with too much current...

Probably.  '54 usually is a couple minutes, even when cp'd

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\08\13@152153 by unknown667

picon face
At 12:52 PM 8/13/97 -0600, Shane Nelson wrote:
>> What programmer/eraser were you using?
>Picstart Plus Development Programmer, and a Logical Devices, inc UV
>Eraser.

But you can still program other chips, right?  The programmer wasn't damaged?

---
Unknown

1997\08\13@154332 by Shane Nelson

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face
On Wed, 10 Sep 1997, unknown667 wrote:

> At 12:52 PM 8/13/97 -0600, Shane Nelson wrote:
> >> What programmer/eraser were you using?
> >Picstart Plus Development Programmer, and a Logical Devices, inc UV
> >Eraser.
>
> But you can still program other chips, right?  The programmer wasn't damaged?
>
> ---
> Unknown

The programmer works fine. I think i fried the chips in-circuit. In fact,
I know I over did the current on a few of them by shorting (accidently)
pins together..

-Shane.

1997\08\13@154340 by Shane Nelson

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On Wed, 13 Aug 1997, Andy Kunz wrote:

> >I have a dozen 'c54 chips that won't erase. I'm thinking I probably fried
> >them with too much current...
>
> Probably.  '54 usually is a couple minutes, even when cp'd
>
> Andy

Couple minutes?? Wow. I find they need at least 20. I wonder if it's
possible to damage them by UV exposure, or  by just leaving them
under normal flourscent lighting.. I usually don't cover the window when
testing.

-Shane.

1997\08\13@155117 by unknown667

picon face
At 03:08 PM 8/13/97 -0400, Martin R. Green wrote:
{Quote hidden}

I've got 8 chips exhibiting this behaviour, and I tried erasing for 20 min.
without success.  I'm using relatively old chips, I believe, but even with
the code protection, would 20 min. be reasonable?

---
Unknown

1997\08\13@161416 by Andy Kunz

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face
>I've got 8 chips exhibiting this behaviour, and I tried erasing for 20 min.
>without success.  I'm using relatively old chips, I believe, but even with
>the code protection, would 20 min. be reasonable?

If they aren't "A" suffix parts, should be fine.  Try a longer exposure, or
a new bulb.  How quickly do other chips erase for you?

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\08\13@161421 by Andy Kunz

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face
>Couple minutes?? Wow. I find they need at least 20. I wonder if it's

You probably need a new bulb.

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\08\13@175459 by unknown667

picon face
At 04:13 PM 8/13/97 -0400, Andy Kunz wrote:
>>I've got 8 chips exhibiting this behaviour, and I tried erasing for 20 min.
>>without success.  I'm using relatively old chips, I believe, but even with
>>the code protection, would 20 min. be reasonable?
>If they aren't "A" suffix parts, should be fine.  Try a longer exposure, or
>a new bulb.  How quickly do other chips erase for you?

Actually, they are 16C74A... ?

---
Unknown

1997\08\13@175504 by unknown667

picon face
At 04:13 PM 8/13/97 -0400, Andy Kunz wrote:
>>I've got 8 chips exhibiting this behaviour, and I tried erasing for 20 min.
>>without success.  I'm using relatively old chips, I believe, but even with
>>the code protection, would 20 min. be reasonable?
>If they aren't "A" suffix parts, should be fine.  Try a longer exposure, or
>a new bulb.  How quickly do other chips erase for you?

They're 16C74A and no chips that I have work.  All I have available are
16C74A chips, all of which don't seem to work.  I called Microchip in
Toronto, but they were closed at the time... probably call them tomorrow
and ask what their opinion is.  I think the programmer's fried.

---
Unknown

1997\08\13@180336 by Matt Bonner

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unknown667 wrote:
>
> At 04:13 PM 8/13/97 -0400, Andy Kunz wrote:
> >>I've got 8 chips exhibiting this behaviour, and I tried erasing for 20 min.
> >>without success.  I'm using relatively old chips, I believe, but even with
> >>the code protection, would 20 min. be reasonable?
> >If they aren't "A" suffix parts, should be fine.  Try a longer exposure, or
> >a new bulb.  How quickly do other chips erase for you?
>
> They're 16C74A and no chips that I have work.  All I have available are
> 16C74A chips, all of which don't seem to work.  I called Microchip in
> Toronto, but they were closed at the time... probably call them tomorrow
> and ask what their opinion is.  I think the programmer's fried.
>
I've experimented with cp'd and non-cp'd 16C74A's and my decade old
Spectroline UV eraser.  Non-cp'd: 10 minutes.  Cp'd: between 1.5 and 2
hours.  I've only checked for erasure with my Picstart-16C - my Promate
II came last week and I haven't checked erased cp'd parts over the full
voltage range.  I'll be trying the same thing with 16C61's when my order
arrives.
--Matt

1997\08\13@183010 by Martin R. Green

picon face
Don't sweat the fluorescent lighting.  It takes me a couple of minutes to
erase most PIC's with my DataErase II, about 60 to 240 minutes with a
commercial U/V (black light) tube, and I've left PIC's and Eproms under
fluorescent light for weeks with no damage.

The short times described in the original post are with high intensity U/V
tubes like that in the DataErase.


CIAO - Martin R. Green
EraseMEelimarspam_OUTspamTakeThisOuTbigfoot.com

----------
From:   Shane Nelson[SMTP:ispamspam_OUTCHEETAH.SPOTS.AB.CA]
Sent:   Wednesday, August 13, 1997 3:39 PM
To:     @spam@PICLISTKILLspamspamMITVMA.MIT.EDU
Subject:        Re: frying a PIC

On Wed, 13 Aug 1997, Andy Kunz wrote:

> >I have a dozen 'c54 chips that won't erase. I'm thinking I probably
fried
> >them with too much current...
>
> Probably.  '54 usually is a couple minutes, even when cp'd
>
> Andy

Couple minutes?? Wow. I find they need at least 20. I wonder if it's
possible to damage them by UV exposure, or  by just leaving them
under normal flourscent lighting.. I usually don't cover the window when
testing.

-Shane.

1997\08\13@183222 by Martin R. Green

picon face
20 minutes would not be a long time, I've heard numbers up to several hours
for the configuration bits on devices that used to take <10 minutes before
Microchip improved the security.  Of course, they might really be fried,
but try erasing them with a high intensity UV tube like the DataErase for
several hours before you junk 'em.

Martin R. Green
KILLspamelimarKILLspamspambigfoot.com

----------
From:   unknown667[SMTP:RemoveMEunknown667TakeThisOuTspamHOTMAIL.COM]
Sent:   Wednesday, September 10, 1997 3:40 PM
To:     spamBeGonePICLISTspamBeGonespamMITVMA.MIT.EDU
Subject:        Re: frying a PIC

At 03:08 PM 8/13/97 -0400, Martin R. Green wrote:
>You might not have fried them after all.  I have heard that one of the
ways
>MicroChip increased the security of their devices is to increase the UV
>exposure needed to erase the configuration bits.  This is because some
>enterprising souls figured out how to manipulate the chip voltage and
>erasure techniques to clear the code protect bit while still leaving the
>code itself intact.  By making the configuration bits much harder to
erase,
>the contents of the program memory will be gone by the time the protect
bit
{Quote hidden}

I've got 8 chips exhibiting this behaviour, and I tried erasing for 20 min.
without success.  I'm using relatively old chips, I believe, but even with
the code protection, would 20 min. be reasonable?

---
Unknown

1997\08\13@220817 by Patrick J.

flavicon
face
Martin R. Green wrote:
>
> Don't sweat the fluorescent lighting.  It takes me a couple of minutes to
> erase most PIC's with my DataErase II
>
> The short times described in the original post are with high intensity U/V
> tubes like that in the DataErase.
>
> CIAO - Martin R. Green
> RemoveMEelimarspamTakeThisOuTbigfoot.com


My 16C74 and 16C74A erasers in about 10 minutes (no CP) with DataErase
II.
16C55 takes less than 2 minutes.

A few days ago my DataErase II went into the electronics heven...
The tube is ok, just wont light up. Works in another DataErase II.
The electronics want to 'light up' while smoking a lot :-)
(Witch remains me of a thread : "Reliability thinking and risk
assesment")

Does anyone know what it takes to get the tube to light.
Dosen't seem to need mutch more than 12V to get it started.
Suppose it need AC, what freq. and voltage ?
Perhaps it is possible to build some simple circuit to get it going
again?

  ? ---+    UV    +--- ?
       8   TUBE   8
  ? ---+          +--- ?

1997\08\13@230235 by TONY NIXON 54964

flavicon
picon face
> Does anyone know what it takes to get the tube to light.
> Dosen't seem to need mutch more than 12V to get it started.
> Suppose it need AC, what freq. and voltage ?
> Perhaps it is possible to build some simple circuit to get it going
> again?

I've been using an inverter from one of those 12V fluoro lights that
are powered by a car cigarette lighter for about 6 years now without
even a tube failure. These lights are very cheap and I use a simple 12V
power supply for it.

Regards

Tony


Just when I thought I knew it all,
I learned that I didn't.

1997\08\13@234359 by Mike Keitz

picon face
On Thu, 14 Aug 1997 12:27:24 +1000 TONY NIXON 54964
<Tony.nixonEraseMEspam.....ENG.MONASH.EDU.AU> writes:
>> Does anyone know what it takes to get the tube to light.
>> Dosen't seem to need mutch more than 12V to get it started.
>> Suppose it need AC, what freq. and voltage ?
>> Perhaps it is possible to build some simple circuit to get it going
>> again?
>
>I've been using an inverter from one of those 12V fluoro lights that
>are powered by a car cigarette lighter for about 6 years now without
>even a tube failure. These lights are very cheap and I use a simple
>12V
>power supply for it.


Those tubes are fluorescent tubes, the only difference is "cosmetic".
Unlike a regular fluorescent tube, the UV tube has no phosphor coating on
the inside and the "glass" is quartz so UV can pass through (ordinary
glass blocks UV).  But it has the same electrodes and mercury fill as a
regular fluorescent.  So any circuit that will light up a similar-sized
fluorescent tube will work with them.  Either the classic AC line through
ballast inductor, or the DC-AC converter type could be used.


'frying a PIC'
1997\09\03@145451 by Larry G. Nelson Sr.
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face
I talked to som Microchip Engineers at the masters conference in Arizona
this summer and was told there is no problem "cooking" the chips in the
eraser. They do state that if you set the code protect the chip will not
erase but I have seen some erased in a lon period of time. I believe they
are still refining the way code protect works and it may be in the  future
the chip will never erase. If you want to set code protect use an OTP. When
you program windowed parts always check the code protect status.


At 06:21 PM 8/13/97 -0400, you wrote:
{Quote hidden}

Larry G. Nelson Sr.
RemoveMEL.NelsonTakeThisOuTspamspamieee.org
http://www.ultranet.com/~nr

1997\09\03@170636 by Eric van Es

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face
Larry G. Nelson Sr. wrote:
>
> I talked to som Microchip Engineers at the masters conference in Arizona
> this summer and was told there is no problem "cooking" the chips in the
> eraser. They do state that if you set the code protect the chip will not
> erase but I have seen some erased in a lon period of time. I believe they
> are still refining the way code protect works and it may be in the  future
> the chip will never erase. If you want to set code protect use an OTP. When
> you program windowed parts always check the code protect status.
>
>
> Larry G. Nelson Sr.
> EraseMEL.NelsonspamspamspamBeGoneieee.org
> http://www.ultranet.com/~nr

If I remember correctly there are no 16C84 OTP's...
Bang goes that theory then...
--
Eric van Es               | Cape Town, South Africa
RemoveMEvanesKILLspamspamilink.nis.za | http://www.nis.za/~vanes
LOOKING FOR TEMPORARY / HOLIDAY ACCOMODATION?
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