pic16f819 fried pins

[BrunoG]

Hi,

A brand new pic16f819 fried under my eyes : it was running on my easypic2
development board, with nothing else than leds on its outputs, when I saw
the RB6 and RB7 leds dimming and then turning off. After that, I was unable
to flash it again (RB6 and RB7 are the programming pins). And all others
pins work well...

This chip was brand new, has only a very few cycles of flash writes (a
dozen), has never been loaded on its ouptuts, and my board runs perfectly
well (I tried after that to flash and run some other pics of p16 & p18
family without any problem).

I fried by myself some pics, but I never saw a pic frying of its own 8-(

As it is not 100% dead, I wonder if it is a defective chip or something
else.

Does anybody here did experiment the same issue ?

Thanks !

Bruno
http://www.micro-examples.com/public/microex-navig/doc/200-pic-microcontroller-examples.html

 

[Roger Hamlett]

Hi,

A brand new pic16f819 fried under my eyes : it was running on my
easypic2 development board, with nothing else than leds on its outputs,
when I saw the RB6 and RB7 leds dimming and then turning off. After
that, I was unable to flash it again (RB6 and RB7 are the programming
pins). And all others pins work well...

This chip was brand new, has only a very few cycles of flash writes (a
dozen), has never been loaded on its ouptuts, and my board runs
perfectly well (I tried after that to flash and run some other pics of
p16 & p18 family without any problem).

I fried by myself some pics, but I never saw a pic frying of its own 8-(

As it is not 100% dead, I wonder if it is a defective chip or something
else.

Does anybody here did experiment the same issue ?

Thanks !

Bruno
http://www.micro-examples.com/public/microex-navig/doc/200-pic-microcontroller-examples.html

One 'comment', leaps out at me here. "Nothing else than LEDs on it's
outputs". I hope there are some current limiting resistors as well?. If
not, then the outputs will have been massively overloaded....

Best Wishes

 

[BrunoG]

One 'comment', leaps out at me here. "Nothing else than LEDs on it's
outputs". I hope there are some current limiting resistors as well?. If
not, then the outputs will have been massively overloaded....

Best Wishes

Yes sure, the easypic has its own limiting resistors on board
I just mean : no extra load or extra device connected to the outputs...

Thanks !

Bruno
http://www.micro-examples.com/public/microex-navig/doc/200-pic-microcontroller-examples.html

 

[Rune Christensen]

Yes sure, the easypic has its own limiting resistors on board
I just mean : no extra load or extra device connected to the outputs...

Thanks !

Bruno
http://www.micro-examples.com/public/microex-navig/doc/200-pic-microcontroller-examples.html

Have you tried to remove and reinsert the chip sometimes the chips could
latch up due to some extreme/unlucky condition?

There will always be a failure rate of these chips maybe you were just
unlucky and got a faulty chip :-(

Regards
Rune

 

[Winfield Hill]

Rune Christensen wrote...

Roger Hamlett wrote...
BrunoG wrote ...

A brand new pic16f819 fried under my eyes : it was running on my
easypic2 development board, with nothing else than leds on its
outputs, when I saw the RB6 and RB7 leds dimming and then turning
off. After that, I was unable to flash it again (RB6 and RB7 are
the programming pins). And all others pins work well... [ snip ]

One 'comment', leaps out at me here. "Nothing else than LEDs on it's
outputs". I hope there are some current limiting resistors as well?.
If not, then the outputs will have been massively overloaded....

Yes sure, the easypic has its own limiting resistors on board
I just mean : no extra load or extra device connected to the outputs...

Have you tried to remove and reinsert the chip sometimes the chips
could latch up due to some extreme/unlucky condition?

There will always be a failure rate of these chips maybe you were
just unlucky and got a faulty chip :-(

Ahem. Did Bruno fail to tell us about a fully-charged 2.2uF 180V
capacitor "coming from a nixie power supply" that he discharged into
the RB7 pin and its associated '4053 cmos switch IC? "Nothing else
than LEDs on it's outputs," he says... Ahem.

http://www.micro-examples.com/public/microex-navig/doc/900-prog-led

 

[BrunoG]

No Win, that was another issue and the anolog switch acted like a fuse, and
the pic16f84a that was on the board was intact ! This time it is a pic16f819
who slowly died...

Anyway if I find the reason I'll write a paper about it ;-) !

Thanks,

Bruno
http://www.micro-examples.com/public/microex-navig/doc/200-pic-microcontroller-examples.html

 

[BrunoG]

Have you tried to remove and reinsert the chip sometimes the chips could
latch up due to some extreme/unlucky condition?

There will always be a failure rate of these chips maybe you were just
unlucky and got a faulty chip :-(

Regards
Rune

Yes I did, but without success. The pic seems to be lachted up as you say,
because it still runs, but RB6 & RB7 are inoperent...

Bruno
http://www.micro-examples.com/public/microex-navig/doc/200-pic-microcontroller-examples.html

 

[Stef Mientki]

Yes I did, but without success. The pic seems to be lachted up as you say,
because it still runs, but RB6 & RB7 are inoperent...

Bruno
http://www.micro-examples.com/public/microex-navig/doc/200-pic-microcontroller-examples.html

How foolish this may sound, try it tomorrow again!!
Me and someone else have seen such a phenomena,
when programming the chip with a "not-so-good" programmer.
And let me hear if you are the third person !!

Stef Mientki

 

[BrunoG]

How foolish this may sound, try it tomorrow again!!
Me and someone else have seen such a phenomena,
when programming the chip with a "not-so-good" programmer.
And let me hear if you are the third person !!

Stef Mientki

Hi Stef, I give the pic a little bit rest and and will try later as you say
: I'll tell you tomorrow more about its health...
I never, ever, had any problem to write a pic with the easypic board !
That's why I'm so surprised, I wrote pics thousand of times.
Maybe some software or fuses configuration may have cause this kind of
problem to other people ?

Thanks !

Bruno
http://www.micro-examples.com/public/microex-navig/doc/200-pic-microcontroller-examples.html

 

[Pooh Bear]

Hi Stef, I give the pic a little bit rest and and will try later as you say
: I'll tell you tomorrow more about its health...
I never, ever, had any problem to write a pic with the easypic board !
That's why I'm so surprised, I wrote pics thousand of times.
Maybe some software or fuses configuration may have cause this kind of
problem to other people ?

When micros get slightly 'hurt' they often lose the ability to be re-programmed.

Graham

 

[Ian Stirling]

No Win, that was another issue and the anolog switch acted like a fuse, and
the pic16f84a that was on the board was intact ! This time it is a pic16f819
who slowly died...

Anyway if I find the reason I'll write a paper about it ;-) !

Are you very sure you always observed proper anti-static precautions?
Very, very odd stuff happens when static hits chips, it can cause odd
delayed failures.

 

[Apostrophe Police]

One 'comment', leaps out at me here. "Nothing else than LEDs on it's
outputs".

No, the OP said, "leds on its outputs", and didn't introduce the
extraneous apostrophe.

One demerit assessed.

 

[Winfield Hill]

BrunoG wrote...

No Win, that was another issue and the anolog switch acted like a
fuse, and the pic16f84a that was on the board was intact! This
time it is a pic16f819 who slowly died...

Anyway if I find the reason I'll write a paper about it ;-) !

What was your charged 2.2uF 180V capacitor doing this time around?

 

[BrunoG]

Are you very sure you always observed proper anti-static precautions?
Very, very odd stuff happens when static hits chips, it can cause odd
delayed failures.

GOOD Ian, I think you got it.

The only difference between the defective pic and the other ones, is that I
bought it to my local dealer's store, instead of getting it directly by post
delivery from my usual supplier. Of course it increases static hits
exposures due to extra handling.

Thanks !

Bruno
http://www.micro-examples.com/public/microex-navig/doc/200-pic-microcontroller-examples.html

 

[Someone]

BrunoG wrote...

What was your charged 2.2uF 180V capacitor doing this time around?

waiting to zap another day? hehehe!

 

[Winfield Hill]

BrunoG wrote...

Ian Stirling wrote...

GOOD Ian, I think you got it.

The only difference between the defective pic and the other ones, is
that I bought it to my local dealer's store, instead of getting it
directly by post delivery from my usual supplier. Of course it
increases static hits exposures due to extra handling.

That's a 150pF capacitor charged to say 3kV, compared to your 2.2uF
capacitor charged to 2.2uF 180V. The first has 0.7mJ of energy,
compared to 35mJ for the second. But 0.7mJ is more than enough.

It only takes one small spark, which you may have administered.

 

[BrunoG]

Hi Win,

BrunoG wrote...

What was your charged 2.2uF 180V capacitor doing this time around?

I was building a nixie power supply for a single-nixe pic16f8Aa dcf77 little
clock, the program and schematic will be soon released on my web site ;-)


Thanks,

Bruno
http://www.micro-examples.com/public/microex-navig/doc/200-pic-microcontroller-examples.html