AnsweredAssumed Answered

MSCAN module, CANCTL1_CANE... possible to go from 1 to 0?

Question asked by Chris Pawlak on Feb 24, 2014
Latest reply on Feb 26, 2014 by TomE

I'm working with the MCF51JM128 Coldfire Microcontroller. Is it at all possible to change CANCTL1_CANE from 1 to 0?  I understand that CANE is write-once, but the following from the MCF51JM128 reference manual seems to imply there is a way around that. Regarding the CANCTL1 register:

 

Write: Anytime when INITRQ = 1 and INITAK = 1, except CANE that is write once in normal and

anytime in special system operation modes when the MSCAN is in initialization mode (INITRQ = 1 and

INITAK = 1).

 

I already found out that merely putting MSCAN in initialization mode is not enough to be able to change CANE to 0. What are these "special operation modes," and would they indeed allow me to change CANE to 0?

 

The reason I'm asking is that I would like to be able to temporarily use the TXCAN pin as a GPIO for diagnostic purposes, but at a point after which the MSCAN module has already been enabled (i.e. CANCTL1_CANE = 1).  And I would like to do this without having to do a hard reset on the microcontroller.

Outcomes