SPRUIE9D May 2017 – May 2024 DRA74P , DRA75P , DRA76P , DRA77P
The external loopback mode is similar to the loopback mode; however, it includes the signal path from CAN core to Tx pin, the Tx pin itself, and the signal path from Tx pin back to CAN core. When external loopback mode is selected, the input of the CAN core is connected to the input buffer of the Tx pin.
With this configuration, the Tx pin IO circuit can be tested.
External loopback mode can be activated by setting bit DCAN_TEST[8] EXL to 1.
Figure 26-184 shows the connection of signals CAN_TX and CAN_RX to the CAN core in external loopback mode.
When loopback mode is active (LBACK bit set), the EXL bit will be ignored.