SPRUJ53B April 2024 – September 2024 TMS320F28P550SJ , TMS320F28P559SJ-Q1
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 controller and peripheral mode. The following examples demonstrate these considerations.
In 3-wire controller mode, SPICLKx, SPIPTEx, and SPIPICOx pins must be configured as SPI pins (SPIPOCIx pin can be configured as non-SPI pin). When the controller transmits, the controller receives the data the controller transmits (because SPIPICOx and SPIPOCIx are connected internally in 3-wire mode). Therefore, the junk data received must be cleared from the receive buffer every time data is transmitted.