CAN-FD External loopback test in iMXRT1180

[vilas_shetty]

Hello community,

i am trying to test CAN-FD in iMXRT1182 EVK for external loopback but in the mcuXpresso sdk i only find example for internal loopback testing. Can anyone help me out in performing  external loopback test. Also help me out whether i can short TX to RX pin directly in the board to have external loopback connectivity.

#IMXRT1182# MCUXpresso-IDE 

[Gavin_Jia]

Hi @vilas_shetty ,

Thanks for your interest in NXP MIMXRT series!

RT1180 FlexCAN provides these operation modes:

This loopback mode is what you call internal loopback mode, which is used for self-testing, but in this mode the Tx and Rx pins are not able to detect any external signals.

In the meantime, I've checked other sources and found the difference between the external loopback mode and the internal loopback mode you mentioned in comparison:

So I don't think the external loopback mode you mentioned can be implemented on the RT1180. 

Best regards,
Gavin

[vilas_shetty]

Hello Gavin_Jia,
Then how can i test the CAN-FD ? do you have any other methods

[Gavin_Jia · Accepted solution]

Hi @vilas_shetty ,

Thanks for your input.

As we discussed earlier, the internal loopback mode can only be used for self-testing to verify that the CAN controller is functioning properly.The external loopback mode, on the other hand, can be used to test the hardware, i.e., the entire system's physical layer and communication functions properly.

Although the RT1180 does not provide an external loopback mode, and there is a slight difference between using external Rx and Tx connections and the directly provided external loopback mode, it is basically equivalent. You can use this approach for testing. Also, using a dedicated external CAN analyzer, etc. can help you verify that the entire communication link is working properly.

Best regards,
Gavin