DCAN
CAN_TX
CAN Core
Rx
Tx
pin
CAN_RX
pin
Test Modes
1451
SPNU563A – March 2018
Copyright © 2018, Texas Instruments Incorporated
Controller Area Network (DCAN) Module
27.14.3 External Loop Back Mode
The External Loop Back Mode is similar to the Loop Back 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
Loop Back 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 Loop Back Mode can be activated by setting bit ExL in Test Register to 1.
shows the connection of signals CAN_TX and CAN_RX to the CAN Core in External Loop
Back Mode.
NOTE:
When Loop Back Mode is active (LBack bit set), the ExL bit will be ignored.
Figure 27-18. CAN Core in External Loop Back Mode