49.7.8 Local Loopback Test Mode

Local Loopback mode connects the output of the transmitter directly to the input of the receiver, as shown in the figure below. The MISO pin has no effect on the receiver and the MOSI pin is driven as in normal mode.

The MOSI, SPCK and NPCSx are normally transmitted unless the PIO is configured to drive logical values to prevent the SPI external target device from starting.

Local Loopback mode allows a quick and easy verification of the transmitter and receiver logic.

Local Loopback mode is enabled when SPI_MR.LLB=1 and SPI_MR.MSTR= 1.

Figure 49-21. Local Loopback Mode Configuration