Thanks again for all this support.
I have perfect comms using the HW SPI library. I use the exact same code, substituting calls to encapsulated versions of NG's code for the various HW calls.
My HW SPISettings call is:
And my USART setup call is:
pinMode (MSPIM_SS, OUTPUT); // SS
// must be zero before enabling the transmitter
UBRR0 = 0;
UCSR0A = _BV (TXC0); // any old transmit now complete
pinMode (MSPIM_SCK, OUTPUT); // set XCK pin as output to enable master mode
UCSR0C = _BV (UMSEL00) | _BV (UMSEL01); // Master SPI mode
UCSR0B = _BV (TXEN0) | _BV (RXEN0); // transmit enable and receive enable
// must be done last, see page 206
UBRR0 = 0; // full speed //3 // 2 Mhz clock rate
The MOSI signals are the same, but the replies are not. I cannot understand why.
I use the same code, so the same delayMicroseconds calls are made to ensure that there is enough time.
I am at a loss, but thank you so much for your help!