TMS320F280049: CAN module reset process

Hi Luke,

Checking back with design if there are differences between the two module reset methods but on a high level, SOFTPRES works by first clearing the corresponding bit (SOFTPRES10,CANA -> '0') then immediately setting it (SOFTPRES10,CANA -> 1).  For CAN_CTL.SWR, module reset is initiated by setting this bit (CAN_CTL.SWR -> '1') but it requires that CAN_CTL.INIT bit is set first prior to setting the SWR bit.  Will get back with you on this topic once I get design confirmation on other differences.

Regards,

Joseph

Joseph,

Yes, please help with this.

I would like to understand the differences between these two reset methods, which registers will reset to default value?

Thanks for your help.

Luke

Hi Luke,

SORTPRES method resets the entire DCAN module while SWR bit only resets a subset of the module.  SOFTPRES method would put all the CAN registers to default value.

Joseph

Joseph,

If we use below steps to do CAN reset, when we clear CAN_CTL.INIT bit, the CAN transaction should be still working since no user configuration is lost and the logic are reset for next CAN transaction. This is reasonable, is this correct?

1. EALLOW
2. set CAN_CTL.INIT
3. set CAN_CTL.SWR
4. loop check SWR=0
5. clear CAN_CTL.INIT
6. EDIS

Regards,

Luke

Luke,

Yes, with the above configuration, user settings are preserved and CAN transactions will be carried out after the above SW reset seqence.

Regards,

Joseph