Initialize the SPI to a basic functional state by following these steps:
- 1.Configure the SS pin in the Port peripheral.
- 2.Select SPI Master / Slave operation
by writing the Master/Slave Select bit (MASTER) in the Control A register
(SPI.CTRLA).
- 3.In Master mode, select the clock
speed by writing the Prescaler bits (PRESC) and the Clock Double bit (CLK2X) in
SPI.CTRLA.
- 4.Optional: Select the data transfer
mode by writing to the MODE bits in the Control B register (SPI.CTRLB).
- 5.Optional: Write the Data Order bit
(DORD) in SPI.CTRLA.
- 6.Optional: Setup buffer mode by writing BUFEN and BUFWR bits in the Control B
register (SPI.CTRLB).
- 7.Optional: To disable the multimaster
support in Master mode, write '1' to the Slave Select Disable bit (SSD) in
SPI.CTRLB.
- 8.Enable the SPI by writing a '1' to
the ENABLE bit in SPI.CTRLA.