STM32F4 Ethernet not responding after power up

[Maor Avni]

Posted on December 29, 2016 at 13:48

We have a STM32F4 MCU on our boards, and recently have witnessed some strange behavior: The ethernet doesn't work after powering up the board. No pings, no TCP connections. 

After pressing the reset button on the board the ethernet starts working. 

The application uses FreeRTOS 8.2.3 and LwiP 1.3.2.

I built a skeleton application using CubeMX and I couldn't see this behavior

The application has lots of legacy drivers so I can't migrate the application to the HAL libraries and the CubeMX. I'll need to solve this problem with the current code base.

We have a bootloader, but the bootloader doesn't come into play yet as it simply jumps straight to the application.

Any pointers?

Thanks,

Maor

[Tesla DeLorean]

Posted on December 29, 2016 at 21:52

You might want to try an effective power-on-reset circuit for the STM32 and PHY, ie something that will threshold the supply, and holds NRST low for 100ms or so after that.

Check spec for PHY wrt the reset pulse width required, and clock start time expectations. Check if you can identify issues with the MAC or PHY state, that lead to the subsequent failure of the ping and TCP/IP packets. ie see if the register or status bit are indicative of the underlying issue.