In the watch dog windowed mode the service routine causes an unhandled exception unless the countdown timer is less than the SWT_WN register.

[CGilm.1]

 However the countdown timer SWT_CO cannot be checked unless the watchdog is disabled. Is there a way check the countdown timer without disabling the watchdog timer. Or is it OK to disable the watchdog timer check the countdown timer the enable the watchdog timer?

[Angelo Castello]

Hello,

As reported by the RM ...

When the watchdog is disabled (SWT_CR[WEN]=0), this field shows the value of the internal down counter. When the watchdog is enabled (SWT_CR[WEN]=1), this field is cleared (the value is 0x0000_0000). Values in this field can lag behind the internal counter value for up to six system plus eight counter clock cycles. Therefore, the value read from this field immediately after disabling the watchdog may be higher than the actual value of the internal counter.

you should be able to read the down counter value both watchdog enable or disable but one explicitly note reports:

1. SWT_CO will reflect the internal value of the counter when WEN=0, and will be read as 0x0000_0000 when WEN=1.

In both cases, watchdog enabled or disable, you should never catch unhandle exception. I'll do soon a check for double confirmation.

Regards