SPRUIE9D May 2017 – May 2024 DRA74P , DRA75P , DRA76P , DRA77P
The slave transmit-only mode is programmable (set the MCSPI_CHxCONF[13:12] TRM bit field [where x = 0] to 0x2) and avoids the requirement for the MPU to read the MCSPI_RXx register (minimizing data movement) only when transmission is meaningful.
To use the McSPI as a slave transmit-only device, the RXx_FULL and RX0_OVERFLOW interrupts and DMA read requests must be disabled due to the state of the MCSPI_RXx register.
When the SPI word transfer completes, the MCSPI_CHxSTAT[2] EOT bit is set (where x = 0).
Figure 26-89 shows a half-duplex system with a master device on the left and a transmit-only slave device on the right. Each time a bit transfers out from the slave, 1 bit transfers in the master. After eight cycles of the serial clock SPICLK, WordB transfers from the slave to the master.