SPRUHM9H October 2014 – May 2024 TMS320F28075 , TMS320F28075-Q1 , TMS320F28076
In addition to the normal SPI initialization, to configure the SPI module for 3-wire mode, the TRIWIRE bit (SPIPRI.0) must be set to 1. After initialization, there are several considerations to take into account when transmitting and receiving data in 3-wire master and slave mode. The following examples demonstrate these considerations.
In 3-wire master mode, SPICLKx, SPISTEx, and SPISIMOx pins must be configured as SPI pins (SPISOMIx pin can be configured as non-SPI pin). When the master transmits, the master receives the data the master transmits (because SPISIMOx and SPISOMIx are connected internally in 3-wire mode). Therefore, the junk data received must be cleared from the receive buffer every time data is transmitted.