Ethernet loosing link

[xRadx]

Hello guys,

I am facing an issue with Ethernet link on Nucleo F746ZG board.
The board was working correctly for many months, but recently it has stared loosing the link : LEDs are blinking, however it's not possible to connect to the boards, the board is not responding to ping and is not visible on router's connected devices list.

There were no changes to the board (HW or SW), some other devices were added to the network, but neither MAC or IP address is duplicated...

Anyone has some ideas of the reason or advice on how to start with troubleshooting this issue?

Thanks in advance

[fpistm]

Hi @xRadx
Are you able to test with an other board?

[xRadx]

Not with the same software, but the same libs/IDE compiled on the same PC I flash firmware on F767ZI. It works w/o any problems from 2months (so nut too long), but also different network.

The F746ZG was working fine for more than 1year...

So it would rather difficult to compare vs other boards etc. I am concern on how to try debug this issue...

[fpistm]

I am concern on how to try debug this issue...

Honestly don't know.
That's why I would suggest to test with an other board F746ZG to see if it is not simply a hw issue.
Example if you used the flash to store some data then at a certain number of iteration flash is no more usable like there is a life cycle of 10k write iteration (just an example).

[xRadx]

The flash is used only at the SW programming stage. Then no writing to the flash at all while a code is running...
I have this board from new and I've flashed it max 100 times. So i it's not this case.

Is there any spot in the lib code where it checks ethernet link periodically?

[fpistm]

The flash is used only at the SW programming stage. Then no writing to the flash at all while a code is running... I have this board from new and I've flashed it max 100 times. So i it's not this case.

OK. As stated just an example.

Is there any spot in the lib code where it checks ethernet link periodically?

Yes, it is called periodically thanks a timer interrupt;
https://github.com/stm32duino/STM32Ethernet/blob/b44edf68e1bb967b2a9df4b4e71c8d2e3ff70b0f/src/utility/stm32_eth.cpp#L318

[xRadx]

I bought another board the same type, but it also looses link...

Reset button does not help. Reconnecting ethernet cable makes even worst - LEDs go OFF and even reset button does not help...
Flashing firmware again also does not help.

The only trick that does the job is changing port on a network swtich the nucleo is connected to. But to the same switch are connected also other devices that works w/o any problems...

I will check if Nucleo will work on the new port and if not then I would try a different switch.

[xRadx]

Unfortunately either with any port and another switch nucleo looses the ethernet link.
I have even changed router, but nothing helps.

[fpistm]

Strange. If you change all hardware involved. There is probably something different than before. But hard to help.
Power?