I know this is late response, but unfortunately I don’t think you can share these pins. I needed something with connectivity to be able to use the rs485 and the ethernet component of the same module and everything I found is that you cannot share the SPI with display/w5500. In fact m5 told me that I couldn’t use the LAN PoE w5500 with the CoreS3 because the rs485 connected to pins that were unavailable on the CoreS3se and CoreS3 so I had to buy the Core basic. If I am wrong, hopefully I am, then maybe someone will reply and we will both benefit.