MSPM0G3507: CAN single message Tx example seeing wrong waveform on TxD

Hi, Crane

According to my previous experience, this SDK code example should be able to communicate normally.

Also, if you want to verify CAN operation, you can try mcan_loopback demo, this demo configure can loopback internal M0.

Regards,

Helic

Hi Helic,

Thanks for your reply.

Loopback example works fine. When setting external loopback, correct CANFD signal can be seen on TxD pin. But when loopback is disabled, the signal on TxD pin is like what's described in last post. Tried to remove the external connection with TxD pin and it behaves the same.

The only difference is the loopback enable function:

DL_MCAN_lpbkModeEnable(MCAN0_INST, DL_MCAN_LPBK_MODE_EXTERNAL, true);

Looking into this function, what it does are:

    *regCccr |= 0x00000080;                   // set CCCR TEST bit
    *regCccr &= (~(0x00000020));              // clear CCCR MON bit (switch between internal and external loopback)
    *regTest |= 0x00000010;                   // set TEST LPBK bit 

Then my question is, should it work to just disable loopback to make normal transmission work? Or is there anything else that needs to be configured when the loopback is disabled?

Thanks!

Crane