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
(SPIn.CTRLA).
- 3.In Master mode, select the clock
speed by writing the Prescaler bits (PRESC) and the Clock Double bit (CLK2X) in
SPIn.CTRLA.
- 4.Optional: Select the Data Transfer
mode by writing to the MODE bits in the Control B register (SPIn.CTRLB).
- 5.Optional: Write the Data Order bit
(DORD) in SPIn.CTRLA.
- 6.Optional: Setup Buffer mode by
writing BUFEN and BUFWR bits in the Control B register (SPIn.CTRLB).
- 7.Optional: To
disable the multi-master support in Master mode, write ‘1’ to the
Slave Select Disable bit (SSD) in SPIn.CTRLB.
- 8.Enable the SPI by
writing a ‘1’ to the ENABLE bit in SPIn.CTRLA.