STM32H7 Independent Watchdog Timeout Limit

[westman]

Per the presentation linked below, the independent watchdog timeout range for the SMT32H7 is from 125 microseconds to 32 seconds. Is 32 seconds a hard limit? We would like to increase this value.

STM32H7-WDG_TIMERS-Independent Watchdog (IWDG)

Thanks in advance for your help.

Regards, Mark

[TDK · Accepted solution]

Yes, it's a hard limit. You can see the clock scheme here:

Slowest update is 32 kHz / 2^8 / 2^12 = 0.305 Hz or about 32 seconds.

Keep in mind LSI accuracy is not perfect and can vary +/- 10% or so. Check datasheet for specifics.