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STM32H755 IWDG1 hardware watchdog in a continuous reboot and unable to recover the board

murali.karicheri
Associate II

I have a STM32H755 based board where we use M7 for BareMetal and M4 to run zephyr OS. We enabled IWDG1 in BareMetal and finds that the Flash erase of Bank 1 (M4 bank1, M7 bank 0) from Zephyr cause a reset and reset cause is IWDG1. Couldn't understand what is the dependency. M7 should be able run code from Bank 0 while erase happens on Bank 1.

Now I have enabled IWDG1 in hardware and the reload value is 5 msec. It continuously reboots and I am unable to connect the STMCubeIDE to halt the Cores from rebooting due to IWDG1. I have enabled Debugger0>Device Settings to have 'Suspend watchdog counters while halted "Enable", but IDE connects and disconnects immediately due to watchdog reboot which happens right away after boot. Is there a way to recover from this state.. Since I am not able to connect debugger or STMCube programmer, I am not able to flip the OB bit for hardware watchdog for IWDG1. Need help

1 ACCEPTED SOLUTION

Accepted Solutions
TDK
Guru

You should be able to connect under reset, or boot into the bootloader by shorting BOOT0 to VDD during reset to connect and recover the device.

If you feel a post has answered your question, please click "Accept as Solution".

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1 REPLY 1
TDK
Guru

You should be able to connect under reset, or boot into the bootloader by shorting BOOT0 to VDD during reset to connect and recover the device.

If you feel a post has answered your question, please click "Accept as Solution".