To perform a diagnostic interconnect check at the digital input pins (the MCU_ERR, NCS, SDI, and SCK pins), the MUX_CFG[1:0] bits in the DIAG_CTRL register must be set to 11b for device interconnect mode. Use the INT_CON[2:0] bits in the DIAG_CTRL register to select which of these digital inputs are multiplexed to the DIAG_OUT pin.

A diagnostic check at the SDO digital-output pin is also possible in DMUX mode. This check uses the sequence that follows:

• Set the INT_CON[2:0] bits in the DIAG_CTRL register to 111b.
• Keep the SPI NCS pin HIGH.
• Use the SPI_SDO bit (bit D6 in the DIAG_CTRL register) to control the state of the SPI_SDO output buffer.

During this SPI_SDO output buffer check, the SPI_SDO input buffer is observed on the DIAG_OUT pin.