Have i blown this PIC?

[Fletcher]

Since i didnt have a 7805 vreg handy to run a 16f628 with 8 leds attached, i ran the pic from a 78l05 and the leds from another 78l05 and i sank the current though the PIC.

I programmed the chip and put it in the circuit and it worked. However ICprog wont allow me to read or write to the PIC anymore. Have i blown up the pic?

 

[Nigel Goodwin]

Since i didnt have a 7805 vreg handy to run a 16f628 with 8 leds attached, i ran the pic from a 78l05 and the leds from another 78l05 and i sank the current though the PIC.

I programmed the chip and put it in the circuit and it worked. However ICprog wont allow me to read or write to the PIC anymore. Have i blown up the pic?

You could have done, what do you mean by 'sank the current though the PIC'?, and what pin was involved.

 

[Fletcher]

i had 8 leds with resistors connected to pins rb0 to rb7. I was using the pic to sink the current from these leds instead of sourcing.

It seems like ive damaged something on the pic related to programming, because it still runs the code i put on the chip in the first place.

 

[Nigel Goodwin]

That doesn't sound like you could have damaged anything!.

What happens when you try and reprogram it?.

 

[Fletcher]

ICprog programs it and it fails verification, when i try to read the code from it there isnt any.

 

[Fletcher]

The only other thing i can think of is that the code i programmed the chip with ended with a SLEEP command. But i dont know if that matters.

 

[Nigel Goodwin]

ICprog programs it and it fails verification, when i try to read the code from it there isnt any.

If the PIC blank after you try to program it?, or does it still have the previous program inside?.

The first part of programming wipes the chip.

If it's not being wiped it's probably not being switched to programming mode.

 

[StupidDum]

try writing simple code to test it

 

[Fletcher]

http://vrplanet.qgl.org/pic.jpg

Thats what i get when i try to read it. But im positive i didnt put code protect or powerup timer on.

 

[0mega]

Hi,

I don't use IC-prog but i'm guessing that you have code protected the code (the drop down box on the side indicates code protect for adress 0-7FF). Try selecting something else (might be "off", or "0-0x000")

That's just a guess though...

Hope that helped,
That shifty dude,
Sadly yours,
inventor of stupid credentials,
JB

 

[Nigel Goodwin]

http://vrplanet.qgl.org/pic.jpg

Thats what i get when i try to read it. But im positive i didnt put code protect or powerup timer on.

Try erasing the chip and reading it again - it should be all $3FFF when erased.

 

[Fletcher]

http://vrplanet.qgl.org/pic.jpg

Thats what i get when i try to read it. But im positive i didnt put code protect or powerup timer on.

Try erasing the chip and reading it again - it should be all $3FFF when erased.

Still the same result. Ill try and get a new pic chip tomorrow.
Theres a guy on https://www.siliconchip.com.au/cms/A_100878/article.html who has built the exact same programmer as me and he is having the same problem. It turns out i must have had the code protect or lvp fuse bit set.

 

[vaineo]

I don't know if you said what programmer your using, but if its a in circuit programmer you might have a component somewhere in the circuit thats drawing to much, i had a 7-Seg led do that, faild on the verify every time untill i removed the 7-Seg display and then it worked fine.