pic16f819 fried pins

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

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

"Roger Hamlett" a écrit dans le message de news: YzLwf.23075$ snipped-for-privacy@newsfe4-gui.ntli.net...

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

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

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

One demerit assessed.

--
Rich Grise, Self-Appointed Chief,
Apostrophe Police

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

--
 Thanks,
    - Win

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

"Winfield Hill" a écrit dans le message de news: snipped-for-privacy@drn.newsguy.com...

"Rune Christensen" a écrit dans le message de news: 43c3a501$0$2503$ snipped-for-privacy@dread14.news.tele.dk...

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

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

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

Graham

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

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.

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.

--
 Thanks,
    - Win

On 10 Jan 2006 15:28:39 -0800, Winfield Hill used recycled pixels to say:

waiting to zap another day? hehehe!

"Ian Stirling" a écrit dans le message de news:

43c3ef19$0$82672$ snipped-for-privacy@ptn-nntp-reader03.plus.net...

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

Hi Win,

"W>>

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