WCH RISC-V Microcontrollers

January 1, 1

Noteworthy chips (IMO)

Chip	Arch	Speed	SRAM	Flash	Power	Notes
CH32V003	V2A	48MHz	2KB	16KB	??
CH32V002	V2C	48MHz	4KB	16KB	2-5V	Pin compatible with V003
CH32V006	V2C	48MHz	8KB	16KB	2-5V
CH32V203	V4B	144MHz	20KB	??KB	3.3V	No PMP, Slow DIV opcode
CH32V305	V4F	144MHz	32KB	??KB	3.3V	FPU
CH32V307	V4F	144MHz	64KB	??KB	3.3V	FPU, Ethernet

More here: https://github.com/ch32-rs/ch32-data#Families

Useful Links

Flashing devices

Via WCH-LinkE (Dongle with CH32V305)

This is the method you want to program bare chips (or modules without a USB port and/or buttons).

Connect the 3.3V, GND, SDIO, and optionally the SDCLK pins to the microcontroller (NOTE: chips with 16 pins or less don’t have a SDCLK pin). These pins are typically found on the backside of the dongle.

Then use wlink.

bash
# list connected
wlink status

wlink flash myprogram.elf

IMPORTANT: Unless you’re programming an older chip like the CH32V2003, your WCH-LinkE probably needs a firmware update. wlink status will report the current firmware version. Newer chips are supported by newer firmwares. At the time of this writing v2.18 is the current version, supporting the CH32V006 family of chips and the CH32V317.

Until wlink adds firmware upgrade support, you can use a separate tool:

https://github.com/cjacker/wlink-iap

The latest firmwares can be found in the WCH-LinkUtility package provided by WCH. For the WCH-LinkE, you want FIRMWARE_CH32V305.bin.

bash
wlink-iap -f ../Firmware_Link/FIRMWARE_CH32V305.bin

The wlink-iap tool will automatically switch to IAP mode, so upgrading firmwares only requires that you do the above.

Via bootloader (ISP/IAP)

You can flash a device using the wchisp tool (link).

NOTE: Uploading data via the booloader is slower than a WCH-LinkE. Also, you can’t dump binaries using the bootloader. More information here.

Installing wchisp

NOTE: You should add udev rules first, otherwise you’ll have to sudo to do anything with the devices.

/etc/udev/rules.d/50-wchisp.rules

udev
SUBSYSTEM=="usb", ATTRS{idVendor}=="4348", ATTRS{idProduct}=="55e0", MODE="0666"
# or replace MODE="0666" with GROUP="plugdev" or something else

bash
# Paste the above in this file
sudo nano /etc/udev/rules.d/50-wchisp.rules

# Reload udev
sudo udevadm control --reload
sudo udevadm trigger

To install wchisp using Cargo:

bash
cargo install wchisp --git https://github.com/ch32-rs/wchisp

Other methods can be found on the wchisp github page.

Running wchisp

If the module has a boot button, hold it while the device powers on (by plugging it in or by pushing reset). You can confirm the device is in bootloadr mode with lsusb.

bash
lsusb
# ...
# Bus 001 Device 005: ID 4348:55e0 WinChipHead
# ...

You can now use wchisp to retrieve information about the attached device.

bash
wchisp info

# 00:28:26 [INFO] Opening USB device #0
# 00:28:26 [INFO] Chip: CH32V203C8T6[0x3119] (Code Flash: 64KiB)
# 00:28:26 [INFO] Chip UID: CD-AB-58-CF-F1-BC-16-38
# 00:28:26 [INFO] BTVER(bootloader ver): 02.70
# 00:28:26 [INFO] Code Flash protected: true
# 00:28:26 [INFO] Current config registers: ff003fc000ff00ffffffffff00020700cdab58cff1bc1638
# RDPR_USER: 0xC03F00FF
#   [7:0]   RDPR 0xFF (0b11111111)
#     `- Protected
#   [16:16] IWDG_SW 0x1 (0b1)
#     `- IWDG enabled by the software, and disabled by hardware
#   [17:17] STOP_RST 0x1 (0b1)
#     `- Disable
#   [18:18] STANDBY_RST 0x1 (0b1)
#     `- Disable, entering standby-mode without RST
#   [23:22] SRAM_CODE_MODE 0x0 (0b0)
#     `- CODE-192KB + RAM-128KB / CODE-128KB + RAM-64KB depending on the chip
# DATA: 0xFF00FF00
#   [7:0]   DATA0 0x0 (0b0)
#   [23:16] DATA1 0x0 (0b0)
# WRP: 0xFFFFFFFF
#   `- Unprotected

To flash:

bash
wchisp flash ./path/to/firmware.{bin,hex,elf}

Again, more information can be found on the wchisp github page.

Via probe-rs

Need to see if this is even Useful

Creating a binary

Start with this.

https://github.com/cjacker/ch32v_evt_makefile_gcc_project_template

It provides a simple script for generating a basic project (NOTE: when I tried it, it was a broken blinky app).

Depending on your chip, this sample project will need to be changed to use an available PIN. The default is D0, which the CH32V002 does not have, so I made mine use D4. Take note of the init code that sets the pin to PP mode (push-pull).