Hi,
I programmed the code protect fuses on a PIC16F628A. I have tried erase the chip thus restting the fuses back to normal using ICProg or WinPic but to no avail. When i read the PIC i either get 3FFF or 0000 and when i try to program it, programming fails altogather. The hardware is OK as i have sucessfully programmed andother PIC16F628A.
Any ideas on how to revice the IC back or shall i conisgn it to the dustbin.
Any help would be greatly appreciated
Regards
Joseph
Question is which programming voltage the programmers you have tried use?. Once the protection fuses are set, a full erase, using a programmer that support the high voltage programming algorithm, is needed to once again access the chip.
Best Wishes
Hmm, you should be able to erase it. You're not using low voltage programming (LVP) are you? I believe you have to use a programmer that supports traditional (HVP) to erase it.
Hi,
Thanks for the information.
I am using High voltage programming (12V) and the supply voltage is
4.85V. Does the PIC tolerate such deviation from the supply during programming?Joseph
I'm not sure what you mean. 4.85V is close enough on the 5V supply, but Vpp should be close to 13V IIRC. Is your programmer applying that much voltage to the /MCLR pin when you program it?
"joseph" schreef in bericht news: snipped-for-privacy@p10g2000cwp.googlegroups.com...
You need a HV programmer that can supply the required high voltage. If memory serves it is 13.5V for the PIC16F628A. You can find the programming specifications at Microchip. Code protection fuses need more power and time to be erased then the others. Which is deliberately done by design to make sure all others are erased before the code protection fuse is. Make sure to select the right component on your programmer. The programming algorithm of the PIC16F628A differs from the one of the PIC16F628.
petrus bitbyter
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