SPRUIU1C July 2020 – February 2024 DRA821U , DRA821U-Q1
When the MCSPI is configured as a controller device with a single enabled channel (MCSPI_MODULCTRL[2] MS = 0 and MCSPI_MODULCTRL[0] SINGLE = 1), the assertion of the SPIEN[i] signal is optional depending on device connected to the controller. In 3-pin mode (MCSPI_MODULCTRL[1] PIN34 = 1) the controller starts transmitting data when a write to the MCSPI_TX_0/1/2/3 register or the FIFO is performed. In 4-pin mode (MCSPI_MODULCTRL[1] PIN34 = 0) the assertion and de-assertion of SPIEN[i] is controlled by software using the MCSPI_CHCONF_0/1/2/3[20] FORCE bit.