ColdFire/68K Microcontrollers and ProcessorsのトピックRe: MCF5211/5213 Watchdog Reset

MCF5211/5213 Watchdog Reset

foreigner — Tue, 10 Apr 2007 01:43:13 GMT

I would like to have a "hard" reset whenever the watchdog times out.

There is a CWRI bit in the CWCR that is supposed to be used for selecting interrupt or reset whenever the watchdog times out. If I then look into the bit descriptions of the CWRI bit I find that selecting 0 for interrupt on timeout is OK but selecting 1 states the following: "Reserved. If a one is written undetermined behaviour will result. Note: If a core reset is required, the watchdog interrupt should set the soft reset bit in the interrupt controller."

Has anyone had any success with this approach or is there another way to get the reset of the micro upon watchdog timeout??

Thanks,

Re: MCF5211/5213 Watchdog Reset

SimonMarsden_de — Wed, 11 Apr 2007 16:42:26 GMT

Hi

I think this is a documentation error. Earlier ColdFire processors could be reset by the Core Watchdog Timer, but this is not available for later processors.

An alternative is to force a reset by writing to the Reset Control Register (RCR) in the Reset Controller Module. You could do this from the interrupt handler of the CWT.

Cheers

Simon

Re: MCF5211/5213 Watchdog Reset

foreigner — Wed, 11 Apr 2007 19:13:49 GMT

Thanks for the info Simon!

I can do it that way, I'm just not sure how well this would work if the program somehow "got lost". Will it still get the correct vector for the interrupt and so on? I know this is not anything that commonly happens but that's kind of the idea for a watchdog right?

I guess an external watchdog is always an option.

Thanks,

Nick