August 18, 2012 at 8:11 pm #20853
It’s working now :)
I had to lower the ISP frequency. When using the ATmega16 it was working great at 460.8 kHz, but for some reason the ATmega644A prefers something lower, so I have it on at 115.2 kHz and I am able to program the device.
Thanks for the response!