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cwatchdogstm32f4lwip

STM32F4 chip resets when ethernet callback runs with IWDG enabled

I'm using an STM32F429ZI chip on my setup. On it I'm using LWIP to handle ethernet packets.

When the controller gets a packet, it runs the callback function and reprograms the flash using one of the IAP examples. We've left the IWDG disabled while creating and testing this section. The section works, but when IWDG is reenabled, if crashes only on this particular callback example.

I have another callback that takes a message and sends back some status stuff. This does work with IWDG enabled.

To be clear, the board only resets on the tftp callback. I've stuff a number of IWDG counter resets all over the tftp file, but it changes nothing. The crash also seems to be different that an IWDG restart.

See tftpserver.c here

Solution

  • Turns out our prescaler was way too low. Upped it from 4 (0.125s) to 16(0.5s). Good facepalm to myself.