36.3 Host Mode

In Host mode, the device controls the SCK line and, as such, initiates data transfers and determines when any clients broadcast data onto the SPI bus.

Host mode can be configured in four different modes, configured by the TXR and RXR bits:
  • Full Duplex mode
  • Receive Only mode
  • Transmit Only mode
  • Transfer Off mode

The modes are illustrated in the following table:

Table 36-1. Host Mode TXR/RXR Settings
TXR = 1TXR = 0
RXR = 1Full Duplex mode

BMODE = 1: Transfer when RxFIFO is not full and TxFIFO is not empty

BMODE = 0: Transfer when RXFIFO is not full, TXFIFO is not empty, and the Transfer Counter is nonzero

Receive Only mode

Transfer when RxFIFO is not full and the Transfer Counter is nonzero

Transmitted data are either the top of the FIFO or the most recently received data

RXR = 0Transmit Only mode

BMODE = 1: Transfer when TxFIFO is not empty

BMODE = 0: Transfer when TXFIFO is not empty and the Transfer Counter is nonzero

Received data are not stored

No Transfers