AVR MKII Programmer

walterf252000 · Joined: 24 Apr 2012 Posts: 33

Hello everyone, i bought this programmer a few months back, and i just noticed something weird, I have been using the Atmega168 chips, and so far i have been able to program them just fine, i just ordered a few more from digi-key but for some reason the new chips won't program, and i noticed the differfence between the one i can program and the new ones is just the part number, although i'm not really sure why that would matter, the new chips i just ordered are Atmega168-20PU, according to the data sheet the only difference between the Atmega168A and Atmega168-20PU is just the speed.
However when i try to program the Atmega168-20PU i get an error, i'm using AVR Studio 5.0, i have tried AVR Studio 4.0 as well but i still get the same issue, it tells me that i can not detect the µController even though the power is applied and the connections are fine.

I hope i'm making sense, i really don't know how to describe this issue, hopefully someone here will shed some light, i've searched the forums but have not found anything that can help me resolve this issue.

thanks in advance to everyone.

Walter

hgrueneis · Joined: 04 Apr 2009 Posts: 906 Location: A-4786 Brunnenthal

Maybe the original fuse setting in those chips is different.
Try to lower the programing frequency to just above 5KHz and erase the chip.
The signature bytes are the same: 1E, 94, 06 (hex).
If that does not work, connect an Oscillator (not a crystal) with approximately 1MHz to xtal1 and try again to erase.
Any other TTL clock source will do too as long as the frequency is not too high.
Make sure that all possible VCC and GND connections are made.
Good luck.
Hubert