Custom PCB, STM32H7 and KSZ8863RLL, RMII

[DavidWahlberg]

Hi

I have made a custom PCB based on STM32H723VGT MCU and KSZ8863RLL with interface RMII. I have followed the Hardware Design Guide for the KSZ8863. Including 100 Ohm impedance from RJ45 to PHY and 50 Ohm impedance from PHY to STM32. Length matching is also done with meanders. 

Without any configuration from CubeMx I am expecting some activity on the LEDS when I plug a ethernet cable in the RJ45 connector.

Are there anyone with experience with the KSZ8863 3-port switch, that have any suggestions? I have added a picture of the schematic. The crossed is not implemented on the board, so please ignore those.

Any help is much appreciated!

Friendly regards, David

[DavidWahlberg]

Hi @LCE 

Happy to hear that you got it working! 🙂

Some other project came on my desk over the summer, but now I have returned to this project.

I have thought of your suggestion of setting 3-bit in register 198, which would make sense. On my custom PCB I have routed the SMI interface, but as @Pavel A.  mentioned about the limited register access, I am trying getting the SPI interface up and running. For that reason I ordered the ksz8863 daughter board (https://www.microchip.com/en-us/development-tool/ac320004-7) to have access the pins as well as multiple strap options. I have wired it up and made the strap option for [P2LED1, P2LED0] = [1 , 0] to enable SPI slave mode. However, still no good response on the MISO line when trying to read 0x00 register (I am expecting a response of 0x88 according to datasheet).

How far have you come you your project? Can you confirm that my SPI transfer is correct?

Friendly regards, David