Hi Cat, This may have already been asked and I missed it but, in your initialization code, do you set the CS pin to OUTPUT before or after you enable the SPI port? If it's done after, an initial low voltage on the pin may be forcing the SPI port into slave mode as soon as it's enabled. Bruce
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Re: [AVR-Chat] Code stuck waiting for SPI transmission but only after power-up. (ATMega644P)
2010-03-15 by Bruce Parham