RTC/API in MPC5606B stops incrementing RTCCNT

[snafu]

Hello

I ran into problem with FIRC clocking RTC/API module. I use the module for periodic wakup during sleep (stop mode -10) Usually it works fine but from time to time, interrupts stop comming and and I discovered, that the RTCCNT timer is not being incremented.

The question is a little vague but is it possible at all, that FIRC can stop under any circumstances?

Thank you for any reply

Regards

Pavel

[lukaszadrapa]

Hi Pavel,

FIRC definitely shouldn't stop if not requested. Have you tried to build just very simple application which use RTC/API for periodical wake up? It sounds rather like some kind of SW issue. Do you have more boards? Can you see the same behavior on all of them?

Regards,

Lukas

[snafu]

Hi Lukas

Thank you for the reply.

The situation happens on more boards so it doesn't seem to problem of the board.

Most of the time wakeup works but I found out one weird thing. When I put zero into RTCVAL in RTCC register, interrupts stop comming (but RTCCNT keeps on incrementing) and when I put other value into RTCVAL interrups work fine.

I looked at other flags in RTCC when 0 is in RTCVAL but all are correctly set (CNTEN, RTCIE are set, CLKSEL is ok).

Is value 0 in RTCVAL somehow special? I didn't find anything about it in reference manual.

Thank you

Pavel

[lukaszadrapa · Accepted solution]

Hi Pavel,

I found out that this has been already reported some time ago. Design team confirmed this behavior - if RTCVAL is zero, interrupts are not triggered. I can see that there was a request to add this information to the reference manual but it has not been processed yet.

So, please avoid writing zero to the registers as a workaround.

Sorry for inconvenience.

Regards,

Lukas

[snafu]

Hi Lukas

thank you for the confirmation of the bug. Workaround is not a problem.

Regards

Pavel