STM32F407VG with LAN8742A through RMII protocol doesn't run

[rgruberski]

Hi! I am looking for help with my own PCB design first running process. I have PCB with STM32F407VG and LAN8742A PHY. I lost the whole day trying to run it without any effect. After powering on, the orange LED is on constantly, and nothing else. I tried it with the program, and the behavior is the same with an erased chip. I have attached schemat parts, clock configuration, and the board state photo.

I tried to set multiple clock configurations, but nothing came up. Maybe I need to add some power sequence at the start of the MCU. I tried many configurations of reset line and the same effect, just nothing. I don't have any idea what I should do more.

I will be grateful for any help and suggestions! Thank you so much for your attention and participation.

[TDK]

Basic questions:

Are you able to connect with STM32CubeProgrammer?

Are you able to debug the code on the board (any code) by stepping through, observing registers, etc?

 

What does "doesn't run" here mean in particular? What are you expecting to happen? Is the orange LED being on problematic? Are you expecting some other LED to light up or thing to happen?

[rgruberski]

Thank you for your reply. The problem has been solved. There was a missing pull-down resistor on one of the lines.

[Humml87]

Hi,

i have the same problem. Where you add a pull-down resistor?

Best regards

Christian