PAx: GPIO Port A pins, labeled PA0 .. PA15
PBx: GPIO Port B pins, labeled PB0 .. PB15
PCx: GPIO Port C pins, commonly PC13 .. PC15 are broken out
Other labels typically present: 3V3, 5V, G (GND), NRST (reset), BOOT (BOOT0), and SWD/RVSWD pads for programming/debug (SWCLK/SWDIO or similar).

For the exact header layout and picture of the silkscreen labels, please refer to the official WeActStudio documentation:

https://github.com/WeActStudio/WeActStudio.BluePill-Plus-CH32

Pins used by this firmware (as referenced in src/main.rs):

PA1: ADC analog input (combined Trigger/Threshold in the 555-timer example)
PB0: Digital output (Q in the 555-timer example)

If you need to map a label to code, use the same letter+number as in the silkscreen. For example, p.PA1 in code corresponds to pin labeled "PA1" on the PCB header, and p.PB0 corresponds to "PB0".

Building

cargo build --release

Wire the MCU’s USB pins to a USB connector:
- D+ (PA12)
- D− (PA11)
- GND and 5V (as appropriate for your board; ensure you have a data-capable cable)

After flashing and powering via USB, your OS should enumerate a virtual serial port (e.g., /dev/ttyACM0 on Linux, COMx on Windows, /dev/tty.usbmodem* on macOS). Open it with any terminal program (baud setting is ignored by CDC but 115200 is fine).

Example:

Linux: screen /dev/ttyACM0 115200
macOS: screen /dev/tty.usbmodemXXXX 115200
Windows: Use PuTTY on the shown COM port.

You can flash the built ELF using wchisp (WCH ISP tool):

wchisp flash target/riscv32imc-unknown-none-elf/release/bms
# or, if using a wrapper on your system/container, the command may be:
# wchip wchisp flash target/riscv32imc-unknown-none-elf/release/bms

Unlock / Remove MCU Protection (fix "checksum error")

Some CH32 devices ship with flash protection enabled. When protected, tools may report a checksum error and refuse to program. You can clear the protection by performing a full chip erase with wchisp. This will erase all flash contents.

Steps:

Ensure WCH-Link/WCH-LinkE is connected to the target and your OS has permissions to access it.
Verify connection and current status:

wchisp info

Mass erase the chip (this also clears protection/lock bits):

* start the device (while pressing boot)
wchisp erase
* powercycle the device (while pressing boot)
wchisp config reset
* powercycle the device again (while pressing boot), flash should not work

Flash your firmware again:

wchisp flash target/riscv32imc-unknown-none-elf/release/bms

Notes:

The target used in this project is CH32V203C8T6; wchisp detects it automatically with WCH-Link.
If your wchisp version differs, run wchisp --help, wchisp erase --help, or consult the tool's README for the exact flag name.
If the tool still reports protection, look for commands named unprotect or protect --off in wchisp --help. The mass/chip erase is the typical way to clear protection.

Debugging

For debugging purposes a container file is provided together with wrapper scripts to start the containerized openocd and riscv-gdb transparently. The wrapper scripts assume that podman is setup.

Starting Debug server

./bin/openocd

Connecting with gdb for interactive debugging

./bin/gdb -f target/riscv32imc-unknown-none-elf/release/bms

README.md Unescape Escape

ch32v203-bms

WeActStudio BluePill Plus CH32 Pin Labels

Building

Unlock / Remove MCU Protection (fix "checksum error")

Debugging

README.md