19.4.1.8.6 SPI Client Mode and Frame Client Mode

This Framed SPI mode is enabled by setting the MSTEN bit (SPIxCON1[5]) to ‘0’, the FRMEN bit (SPIxCON1[23]) to ‘1’ and the FRMSYNC bit (SPIxCON1[22]) to ‘1’. Therefore, both the SCKx and SSx pins will be inputs. The SSx pin will be sampled on the sample edge of the SPI clock. When SSx is sampled active-high or active-low, depending on the FRMPOL bit (SPIxCON1[21]), data will be transmitted on the next transmit edge of SCKx. A connection diagram indicating signal directions for this operating mode is shown in Figure 19-17.

Figure 19-17. SPIx Client, Frame Client Connection Diagram
Note:
  1. In Framed SPI modes, the SSx pin is used to transmit/receive the Frame Synchronization pulse.
  2. Framed SPI modes require the use of all four pins (i.e., using the SSx pin is not optional).
  3. Client Select is not available when using Frame mode as a client device.