stm32f746 ETHERNET issue

[clock.1166]

Hi,

Could anyone help with this problem? Its driving me mad!!!

I have designed an ethernet interface  for an F746-100 MCU

I have changed pins to avoid using Port G and I have used the  circuit below.

The RJ45 connector is a standard RB1-125BAG1A and the ethernet chip is a LAN8742A

Can anyone tell me if there are any mistakes in this?

I cannot get any connection at all - F746-100 will not ping.

Green LED ON and Yellow LED flashes continuously.

I have an STM32F746 - 144 Nucleo with the same software (apart from the two pins that are changed) -works fine.

The 25MHz xtal works OK (same signal on both boards) and the LAN8742_STATUS_OK returns 0  on both boards when I debug.

There appears to be no errors in the setup LAN8742.c or the ethernetif.c when I debug. This code works OK on the NUCLEO board and I can display a small webpage. Both sets of code use only ETH and LWIP, fixed IP, on a standard Cubeide setup. I assume that the only difference is the two GPIO allocations (PG13>PB12 and PG11>PB11) which I have altered in software.

I have the same sort of signals on both boards on TXP/TXN/RXP/RXN

Can some kind soul tell me if there is anything obviously wrong with my hardware?

Thanks.

Chris

[Iyesi.1]

Hello clock.1166,

I have a problem with custom design LAN8742 ic circuit. What is the problem for that there is no signal on the TXD0/TXD1/TXEN pins? There are signals on RXD0/RXD1 and RXN-P, TXN-P pins by the way.

[clock.1166]

Hi - The circuit that I posted works perfectly.

My problem was that the 49.9ohm resistors were incorrect values. After I had changed these - all was OK.

Chris