Pc PIC16F877A-I/P DIP-40

[olymbou]

hi to everyone . i have a board from a viessmann gas heater and it has a Microcontroller - Microchip Pc PIC16F877A-I/P DIP-40 and i whant to buy anather one , do i have to programe it or is it programed. thanks john.

[stj]

Re: Pc PIC16F877A-I/P DIP-40

you have to program it,
and obviously you need the hex file first.

the original is probably protected btw, so dont expect to read the code from it.

[ben7]

Re: Pc PIC16F877A-I/P DIP-40

hi to everyone . i have a board from a viessmann gas heater and it has a Microcontroller - Microchip Pc PIC16F877A-I/P DIP-40 and i whant to buy anather one , do i have to programe it or is it programed. thanks john.

Yes you will very likely have to program it again.

You MIGHT be able to get one pre-programmed, but I don't think you will, unless you take it out of another similar unit that had a different failure.

[olymbou]

Re: Pc PIC16F877A-I/P DIP-40

do they get dameged or unprogramed when they are on in use .i checket everything on the board and did not find nothing (open or closd or burnd )

[mariushm]

Re: Pc PIC16F877A-I/P DIP-40

They don't usually get unprogrammed, flash memory inside has very long retention (decades).
It's possible the chip could be damaged if something connected to it failed, but otherwise they shouldn't just fail all of the sudden.

It's most likely the internal memory is protected (you can't read the hex data from it) so even if you buy a spare mcu or request one as a sample (it's old, almost obsolete so made in small quantity, therefore expensive) you'd still need the code to upload in it and a programmer.
I have a programmer and I could flash one for you but again.. you need the code in the first place.

[stj]

Re: Pc PIC16F877A-I/P DIP-40

it's not rare or expensive - it's worth a few Euro and easy to get in any quantity.
but the code is the prooblem.

[mariushm]

Re: Pc PIC16F877A-I/P DIP-40

I don't want to check again, but it was about 5-6 dollars on microchip's own site. It's 6$ on Digikey: http://www.digikey.com/product-detai...%2FP-ND/446143

They don't even recommend this one for new designs, the 887 is recommended.. which has very minor differences and costs only 2.65$ on Digikey.

You can get more powerful PIC chips for that money, for example you can get pic18f4321 at 3.2$ when getting 10, or 3$ when getting 25.

With 3.4$ (10 quantity) you get get pic18f4550 with usb support, 48mhz, the works... much more powerful and more user friendly (better architecture for C)

[Agent24]

Re: Pc PIC16F877A-I/P DIP-40

Check the obvious - does the PIC have all the power supplies present and correct? If it has a crystal or other clock source check that its functioning.