Second iteration. First version worked fine but decided I needed a factory reset switch and LED's moving to end of PCB.
Designed to fit exactly in "VG-AL53" aluminium enclosure (google it) these are about $7 on aliexpress.
Works with Microchip TCP Lite stack. Firmware is very close but not yet complete.
I have attached the MPLABX XC8 project in a semi-working state below. Basically it is forwarding everything from ethernet to serial but I cannot test the other way until I get my MODBUS slave device setup. I will update this when status goes to finished.
Note the chip works well but is only really suitable for baud rates up to 9600 which is what I am testing it at and what it will be used at. Stack is also only half-duplex, again this is fine due to the 2-wire RS485 which can only transmit or receive but not both.
There are multiple compiler warnings for the Microchip TCPIP Lite stack when this compiles with XC8 but I have left it on test for several hours transferring at full speed and pinging at the same time and it was fine.