Hardware Client Select Control

The SPI module allows for direct hardware control of a Client Select output. The Client Select output (SS_out) is controlled both directly, through the SSET bit, and indirectly by the hardware while the transfer counter is nonzero (see the Transfer Counter section). The SS_out pin is selected with the PPS controls. The SS_out polarity is controlled by the SSP bit.

Setting the SSET bit will assert SS_out. Clearing the SSET bit will leave SS_out to be controlled by the transfer counter. When the transfer counter is loaded, the SPI module will automatically assert SS_out. When the transfer counter decrements to zero, the SPI module will deassert SS_out either one baud period after the final SCK pulse of the final transfer (when CKE/SMP = 0/1) or one half baud period otherwise, as shown in the following figure.

Figure 1. SPI Host SS Operation - CKE = 0, BMODE = 1, TWIDTH = 0, SSP = 0