SPRUII0F May 2019 – June 2024 TMS320F28384D , TMS320F28384D-Q1 , TMS320F28384S , TMS320F28384S-Q1 , TMS320F28386D , TMS320F28386D-Q1 , TMS320F28386S , TMS320F28386S-Q1 , TMS320F28388D , TMS320F28388S
The external loopback mode is similar to the loopback mode; however, the external loopback mode includes the signal path from the CAN core to the Tx pin, and the signal path from the Tx pin back to the CAN core. When the external loopback mode is selected, 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 the ExL bit in Test Register to 1.
Figure 30-6 shows the connection of signals CAN_TX and CAN_RX to the CAN Core in external loopback mode.