Reset

[bernage]

Hi, although I did not put the code program in pic16f876, it gives an LED light in the circuit i set up. I think i need to completely reset pic16. Is the reset with the Mclr tip and button a temporary reset? How can I completely empty Pic16?
Thanks in advance for any info

 

[augustinetez]

To completely empty a Pic16 (or any PIC), you need to use a programmer to erase it.

 

[Nigel Goodwin]

To empty it you simply select the erase option in your programmer software.

But there's no need to, it does exactly that anyway as the first part of programming it.

 

[bernage]

To completely empty a Pic16 (or any PIC), you need to use a programmer to erase it.

I did it so many times but warning pops up “device is not blank” on pickit3 or mplabx ipe screen.

 

[sagor1]

Your screen grabs suggest that some of the program space is corrupted (bad). Erase simply writes FF to every byte, but may or may not verify it was written correctly. A blank check does a read, checking that every program location is FF. If possible, do a read of the chip after erase, and look at the 8f4 location, is there FF before and after? That is, are all locations containing FF except that one byte? Or, are locations after the "bad byte" 8F4 also containing program code?
Have you tried programming some other program into the PIC? It is entirely possible the PIC chip is bad. Does the erase and verify work ok with other 16F876 chips? If so, your chip is bad. If others fail as well, then the programmer may have a fault, or something is not set up properly in the programmer.

 

[Nigel Goodwin]

Your screen grabs suggest that some of the program space is corrupted (bad). Erase simply writes FF to every byte, but may or may not verify it was written correctly.

To clarify further, the programmer doesn't write 0x3FF (not 0xFF) to the PIC, the PIC itself does it - all the programmer does is send the erase command - the PIC then erases all memory in a certain sequence, in order to prevent any attempts to read a protected device. So program memory is erased first, and the fuses are erased last.

A blank check does a read, checking that every program location is FF. If possible, do a read of the chip after erase, and look at the 8f4 location, is there FF before and after? That is, are all locations containing FF except that one byte? Or, are locations after the "bad byte" 8F4 also containing program code?
Have you tried programming some other program into the PIC? It is entirely possible the PIC chip is bad. Does the erase and verify work ok with other 16F876 chips? If so, your chip is bad. If others fail as well, then the programmer may have a fault, or something is not set up properly in the programmer.

Pretty unlikely, as PIC's are incredibly reliable, even when seriously abused.

Is the OP trying to program it in-circuit?, or out of circuit?.