What are the conditions to set/modify/trigger IWDG2? My application runs in secure mode and I do write to 0x5a002000 the trigger value of 0xaaaa, but I still get a IWDG2 reset. No matter what I do I seem not to be able to change the settings.

[42Bastian Schick · Accepted solution]

Solved.

I had to enable the APB4 clock (0x50000200 = 0x8000).

[Kevin HUBER]

Hello @42Bastian Schick​ ,

Yes, you found it. Thanks for coming back to post the solution :).

As explained page 584 in the Reference Manual RM0436 rev5.0: https://www.st.com/resource/en/reference_manual/DM00327659-.pdf

The APB4 clock is needed to access to the IWDGx registers of IWDG2.

Regards,

Kévin

[42Bastian Schick]

The confusion came because the registers could be read. Most often, if the clock is not enabled, you cannot even read the registers.

Cheers

42Bastian