Solved..
Thanks...

Searching these forums is a good place to start. For example:
search.php?keywords=arduino+wdt

There seem to be a few posts with info and solutions to this.

Hello everyone,

How can Enable WDT and set the timeout period (eg. 1 or 2Sec.) in Arduino Uno. also need to be clear it end of main loop.

Regards
Bijumon.

... to function. But after writing my last message, I realized that this option causes the timer to be automatically cleared, which prevented the Arduino from resetting as I had expected. Once I understood this, I re-tested the code without enabling the AutoClear watchdog option and only included ...

Hello Martin, Thank you once again for your help! I have tried the method you mentioned. Here’s what I did: I selected the Arduino Uno board for programming. I enabled the AutoClear watchdog option. I added an LED and connected it to pin D13. I added the following line before starting ...

Hello everyone, I need help with enabling the Watchdog Timer on an Arduino board. I have searched through several articles on the topic, but I wasn't able to fully understand the correct way to enable the Watchdog as needed. I understand that the Watchdog ...

... the esp32 can solve a Knight's tour for a 45 x 45 chess board and the Arduino version here happily solves for 10 x 10. It is slightly odd - for ... 'kludge' - every 1000000 recursive calls it has a 10ms delay to stop wdt issues. Using the heuristic it takes a few ms (on the esp32) even for ...

I didn't try - but the pulse would stay high until the MCU resets?

The attached program demonstrates calling address 0... This works AOK.

WDT is used automatically - on PIC / esp32 etc but not so on AVR - again didn't test this.

Martin

... to reset 2) Call address 0 (see attached) This outputs some text to UART (at 115200 baud) - then resets after 5s and does it again... 3) Using the wdt timer (#import <avr/wdt.h> (for example wdt_enable(WDTO_15MS); ) Martin

... I'll have a fiddle and see if I can get it to use transaction_write. This means the i2c might not be running at 1MHz in the sample? Also - the wdt is indeed kicking in - and this outputs an error message to the USB port every time it overflows. Martin