Forked from https://github.com/smartmx/lwip_study_examples
This is LWIP using the CH32V307 and its on-chip 10M Ethernet PHY
The the lwip configuration file lwipopts.h is src/Drivers/LWIP/arch/lwipopts.h
The platform-specific ethernet file is src/Drivers/LWIP/arch/ethernetif.c
This code is currently based on LWIP 2.1.3 & LWIP contrib 2.1.0
An example project using this library is available at https://github.com/ddrown/ch32v307-lwip-example