SLAU847F October 2022 – March 2026 MSPM0L1105 , MSPM0L1106 , MSPM0L1116 , MSPM0L1117 , MSPM0L1227 , MSPM0L1227-Q1 , MSPM0L1228 , MSPM0L1228-Q1 , MSPM0L1303 , MSPM0L1304 , MSPM0L1304-Q1 , MSPM0L1305 , MSPM0L1305-Q1 , MSPM0L1306 , MSPM0L1306-Q1 , MSPM0L1343 , MSPM0L1344 , MSPM0L1345 , MSPM0L1346 , MSPM0L2116 , MSPM0L2117 , MSPM0L2227 , MSPM0L2227-Q1 , MSPM0L2228 , MSPM0L2228-Q1
The CTL0.CSSEL bit selects which connected peripheral is addressed by the up to 4 CS signals. The bits are controlled by the SPI module in controller or target/peripheral mode. The selected signal is controlled during the transfers.
The chip select signal needs to be provided by the controller in four-wire mode and the chip select polarity can be inverted by configuring the PINCM.CSx.INV register.
In peripheral mode, the clock is provided by the controller and used by the peripheral to capture the data. The peripheral has the option to operate in 3-wire or 4-wire mode. 4-wire mode only accepts data transfers if the CS is activated.
The CTL0.CSCLR bit controls whether the transmit/receive shift register is automatically cleared when the chip select (CS) signal becomes inactive:
When using CTL0.CSCLR = 1, observe these timing constraints to ensure proper synchronization:
These timing requirements help the peripheral resynchronize with the controller after clock-line disturbances or glitches, or during system initialization. This feature applies only when operating in peripheral mode.