CH32V208 Ethernet & Embassy experimentation

This is a test project to test the CH32 ethernet capability and hopefully assist in the development of a proper driver in ch32-hal.

Reference

As can be seen in the Reference Manual, CH32 have two Ethernet controllers:

• A 10/100/1G MAC + 10M PHY or 10/100M PHY - present in the other lines of uC (RM section 27.1)
• A 10M MAC + PHY, no MII interface - present in the CH32V208, CH579 and a few other uC (RM section 27.2)

10/100/1G MAC (CH32V307)

Comparing STM32 RM and CH32 RM indicate that the this MAC is most likely compatible with eth_v1a driver from embassy-stm32:

• present in v1b and v1c, but not in doc:
  • no mention of regs::Dmarswtr
  • no mention of edfe
• present in v1, but not in doc:
  • no mention of MLT
  • no mention of dmasbmr

disclaimer: I didn't check all the registers

This isn't the target of this repo

10M MAC (CH32V208, CH579)

This is the simplest of the two. It's barely more complex than an SPI controller, so a driver can implemented from scratch relatively quickly.

There is a reference usage in openwch/ch32v20x (in C). Note: MournRiverStudio doesn't have HAL for the 32V208 's Ethernet peripheral, and the included SVD doesn't show the same registers as the doc.

It's restrictive on the system clock, as FSYS has to be 60 or 120MHz. Other than that, it's easy to start:

• Init Eth peripheral
  • setup interrupts as required
• Enable Ethernet
  • Set sys clock to 60 or 120MHz
  • Set ETH_10M_EN in EXTEND.CTR (this enables the clock and PHY power)
  • Set ETHPRE in RCC.CFGR0 if sys clock is 120MHz
• Send data (tested, working)
  • set RX DMA (buffer address, len)
  • set TXCRCEN in MACON2
• receive data (TBD)
  • set RX DMA (buffer address, len)
  • set MARXEN in MACON1
  • set RXEN in ECON1

ch32-metapac / ch32-data development branches

The ETH part of the ch32-metapac is still in work-in-progress, so ch32-metapac will have to be built manually from branch add-eth10m of ch32-data.

Building / running this project

This assumes you already installed the RISCV toolchain and wchisp with the WCH-LINKE debug interface.

Any CH32V208 board should be supported without modification, like the CH32V208-EVT, without guarantee.

git clone https://github.com/chmousset/rs-ch32-data.git ch32-data
git clone https://github.com/chmousset/rs-ch32v208-eth.git ch32v208-eth
cd rs-ch32-data
git checkout add-eth10m
./d gen
cd ../ch32v208-eth
cargo run --release