SPRUIL1D May 2019 – December 2024 DRA829J , DRA829J-Q1 , DRA829V , DRA829V-Q1 , TDA4VM , TDA4VM-Q1
The peripheral receive mode is programmable (set the MCSPI_CHCONF_0[13-12] TRM bit field to 0x1).
In receive-only mode, the MCSPI_TX_0 register must be loaded before the MCSPI is selected by an external MCSPI controller device. The MCSPI_TX_0 register content is always loaded into the shift register whether it is updated or not. The TX0_UNDERFLOW event is activated accordingly and does not prevent transmission.
When the MCSPI word transfer completes (the MCSPI_CHSTAT_0[2] EOT bit is set to 1), the received data is transferred to the channel receive register.
To use the MCSPI as a peripheral receive-only device, the TX0_EMPTY and TX0_UNDERFLOW interrupts and the DMA write requests must be disabled due to the state of the MCSPI_TX_0 register.
For a full-duplex transmission, the serial clock (SPICLK) synchronizes shifting and sampling of the information on the two serial data lines. If SPICLK synchronizes on a single serial data line, the data line should be half-duplex.
Figure 12-76 shows a half-duplex system with a controller device on the left and a receive-only peripheral device on the right. Each time a bit transfers out from the controller, 1 bit transfers in from the peripheral. After eight cycles of the serial clock SPICLK, WordA transfers from the controller to the peripheral.