pickit3 trouble PLEASE

[l_gaminde]

Im using a pickit3 and it just started having problems it says it programs and verify but when you try to verify it says it 's not correct 16f876


Programming...
Programming/Verify complete

Verifying...
The following memory regions failed to verify correctly
Program Memory
Address: 00000000 Expected Value: 00002914 Received Value: 00000000
Verify failed

[l_gaminde]

Ok tried two different things hold chip in reset program and then verify works, also powering from external power supply works. guess its a USB port problem are there any good usb add in boards that will stop this problem

[l_gaminde]

Well no that did not help it worked for about 4 times now back to the same cannot verify

[Jerson]

Are you having this problem with just this one chip? Have you tried other chips to eliminate the chance of PK3 being bad?

Another thing you can try before you give up on PK3, update the firmware on the PK3.

You will find this in MPLAB->settings->configuration->manual update.

[HenrikOlsson]

Hi,
When I've had issues with PK3's they seem to all have been related to USB power supply issues.
If used on a laptop make sure you have the computer powered by the mains adapter and try another, short, high quality USB cable. Last time I had issues I had two laptops side by side, the PK3 worked fine on one of them but not on the other. Swapped the USB cable to a better one and everything's fine... (No, I was not powering my circuit "thru" the PK3, just the PK3 itself).

If you're using a desktop computer (which it sounds like you are) you could possibly try a powered USB hub.

Not saying this IS the problem but I've run into a couple of times.

/Henrik.

[l_gaminde]

Thanks Henrik and jerson maybe I have found the answer I have code protect on it has never acted this way before but once I turned it off it started working again. I have tried all your suggestions except the cable with intermittent results, I will find another cable hopefully a tad bit longer also.
Thank you both