Hello,
I have designed a PCB with a STM32F746VET6 microcontroller and LAN8742A physical interface and magnetics. I'm not an expert in Ethernet and I'm not achieving to make it works.
I want to validate this design and I'm trying to do a ping to the device from the PC. For this purpose, I have a program that implements a tcp echo. Trying to perform a ping, always the packets are lost. However, I try the same program in the Nucleo-144 STM32F746 evaluation board and it works. The design that I have to validate has the same electronics that in the evaluation board (micrcontroller + LAN8742A).
I have checked the signals with the oscilloscope, and the pins RXD0 and RXD1 (of the RMII) are always receiving frames. Furthermore, the pin CRS_DV is asserted when RXD0 and RXD1 receive data. Is this good? In the TXD0,TXD1, MDIO and MDC pins there are nothing.
I have also checked the generated REF_CLK signal and is of 50 MHz. This is good.
I have also change the configuration of the Ethernet peripheral to disable the autonegotiation (Speed to 10M and Half Duplex), but it doesn't work.
Any idea? Data received in the RXD pins are from the network traffic? Is it normal and it means that it is running correctly? What things can I check and test?
Any help will be appreciated very much.
Luis
