I am using the mcp4251 digital potentiometer and have it working perfectly with the atmega328p on the bare bones board, I try to port it over to the atmega644p and have no luck getting it to work.
I am using the code from http://www.arduino.cc/en/Tutorial/SPIDigitalPot to get it to work on the 328. I did have to change the channel info to get it to work with both wipers since it requires a different bit set. That can’t be the issue since the chip is expecting them to be those bits.
I tried using #10, #9, and even the actual SS pin which I assume is 12 as the chip select. Set all those pins to output, hooked up the sck and the mosi pins to phisical pins 6 (PB5, MOSI) and 8(PB7, SCK) and nothing seems to work.
any ideas? could my spi.h file be messed up for use in 644?
it does have it commented in the file "// PB4(MISO), PB3(MOSI), PB5(SCK), PB2(/SS) " which is not right on the 644.