I decided to add place for bothy CAN-FD and RS485 as IPC on the module. The design seen from left is CAN at top, RS485 on bottom – switching the module to right we get the oposite. I have the extra space to do it and it allows me to build modules using UART’s only. One of the modules – like this ethernet module can act as gateway between Ether, CAN and RS485.
I have in addition added a SPI Flash 8Mb and SPI FRAM (32Kb) and if I have pins and space I will add USB and/or USART TTL. I did consider TF-Card until I realized that STM32G491 don’t have a HW IO for that. USB is great for just connecting to a PC and download FW using ST’s build in bootloader.