TLF35584, WWD Settings

[FenoK]

I understand that to configure WWD, set the 0x06~0x0A register after trigger in LOW.
Although WWD has been implemented in the system, I am inquiring because it sometimes starts with an increase in Err Cnt in the initial drive.

Does changing the value of the WWD register restart the LOW? Or does CWOW continue with the changed value?

I would like to know which state (INIT, NORMAL) and at which point it is advantageous to change the setting of the WWD.

In the currently configured system, the symptoms are as follows.

1. Trigger at LOW (Initial setting 600ms)
2. Set up WWD-related registers in Protection Registers.
3. Trigger accordingly with the thought that the CW & OW changed to the setting value will continue.

If no. 2 is performed only once, the ERR CNT rises to 2 once, and then the correct trigger gradually continues to converge to 0.
If no. 2 is performed several times (less than 10 times at 10 ms TASK), it operates without increasing ERR CNT.

[Vishnu_Nambrath · Accepted solution]

Hello, 

I think you are asking about the Window watchdog error counter shown below. 
The counter increments by two at every invalid window watchdog triggering and decrements by one at every valid window watchdog triggering. 

This register is type R3 - which means registers that are being reset in case of “Move to INIT” event, FAILSAFE, STANDBY and a POR. You should read "00" if you are moved to these states and no invalid triggering till you read WWDECNT. 

Watchdog configurations will not affect the error counter. 
Even if you disable the window watchdog, error counter will not reset to zero. 

In your tests
case 1: I suspect there could be at least one invalid trigger. Can you please check?
case 2: Can you please check the device is going into any of the states mentioned above? 

Coming to your second question, Watchdog can be configured in INIT, NORMAL and WAKE state depending on the requirements. 

Regards 
Vishnu