Three open-source hardware projects from OSHWhub worth building: a CH32V003F4P6 core-board backplane for learning peripherals, a programmable fingerprint dock keyboard on CH32V203 with shift-register key scanning, and a WCH-LinkW wireless debugger based on CH32V208.
Open Source Hardware Roundup: CH32V003 Backplane, CH32V203 Fingerprint Dock Keyboard, and a WCH-LinkW Wireless Debugger
The OSHWhub open-source hardware platform continues to be a goldmine for WCH RISC-V MCU designs. This week we highlight three projects that cover three skill levels: a $0.10-class learning platform, a practical USB product design, and a professional-grade debugger you can fabricate yourself.
1. CH32V003F4P6 Development Board Backplane (10th LCSC Electronics Design Contest)
A core-board plus backplane design built around the
CH32V003F4P6 (RV32EC QingKe core, 48 MHz, 16 KB Flash, 2 KB SRAM). The core board works standalone as a minimal system, while the backplane exposes the full peripheral set with a matching BOM available directly from LCSC - a very low barrier to reproduce.
Verified peripherals on the backplane:
- 74HC595 shift register, 8-bit serial-in/parallel-out (LED driving and IO expansion)
- Seven-segment display with dynamic scanning and LED chaser
- UART via CH340C USB-to-TTL
- PWM output and ADC sampling (potentiometer)
- TM1650-driven 4x4 matrix keyboard over I2C
- SSD1306 OLED over I2C and ST7735 SPI display
- WS2812 addressable RGB with TIM+DMA driving
Example firmware for every peripheral is published with the project. Two practical constraints worth knowing before you build: the keyboard and LED features share resources (use the display when the keyboard is active), and the ST7735 and seven-segment display cannot run simultaneously.
License: GPL 3.0. An ideal first board if you are teaching yourself RISC-V MCU bring-up - everything here ports directly to the CH32V003 and its newer CH32V003F4P6 siblings.
- Project: https://oshwhub.com/0x49181f36/ch32v003f4p6-development-board-backplane
2. Programmable Fingerprint Dock Keyboard on CH32V203C8T6
A single USB-C cable handles keyboard HID, fingerprint reader, USB 2.0 hub, and power in this dock keyboard design. The main controller is the
CH32V203C8T6 - QingKe V4B core at up to 144 MHz, 64 KB Flash, 20 KB SRAM, dual USB 2.0 full-speed controllers - positioned as a pin-to-pin alternative to the STM32F103C8T6 with roughly three times the performance.
The interesting engineering choice is in key scanning. Instead of a classic key matrix (which would need about 10 GPIOs for 23 switch inputs, plus diodes to defeat ghosting), the design chains
three SN74HC165PW 8-bit parallel-in/serial-out shift registers and reads all 23 inputs (22 keys plus the scroll-wheel click) over SPI with just four GPIOs. Because every key has an independent input, there are no ghost keys, no anti-ghosting diodes, and lower BOM cost.
Other details:
- Internal HSI clock feeds the USB 48 MHz domain - no external crystal needed for USB
- BOOT0-high reset enters the built-in USB bootloader for field firmware updates
- RGB lighting and scroll wheel on dedicated paths; external Flash footprint reserved but not populated
This is a clean reference if you are designing any USB HID product on the CH32V203 family.
- Project: https://oshwhub.com/xiao_wine/project_bjaskmrb
3. WCH-LinkW-R0-1v1-C Wireless Debugger
A self-contained wireless download/debug probe built on the
CH32V208GBU6 (QingKe V4C, 144 MHz, BLE 5.3, 10M Ethernet MAC+PHY, USB FS, CAN, 128 KB Flash, 64 KB RAM). The board pairs a ceramic AN2051-245 antenna with an ME6206A33 LDO and CH217K USB current-limit switch, in a transparent USB stick enclosure.
Modes, cycled with the ModeS button:
- RISC-V mode - native WCH RISC-V download and debug
- ARM-SWD mode - WinUSB device, two-wire SWD debugging for ARM targets
- ARM-JTAG mode - WinUSB device, legacy JTAG compatibility
- High-speed UART up to 921600 baud
Firmware upgrades over USB without disassembly, and the 3.3 V/5 V target power output is software-controlled. It works out of the box with MounRiver Studio, WCH-LinkUtility, and Keil uVision5 (5.25+).
- Project: https://oshwhub.com/huashuo0804/wch
Why These Three Work Well Together
| Project | MCU | Skill Level | Best For |
|---|
| V003 Backplane | CH32V003F4P6 | Beginner | Learning peripherals end to end |
| Fingerprint Dock Keyboard | CH32V203C8T6 | Intermediate | USB HID product design, shift-register scanning |
| WCH-LinkW Debugger | CH32V208GBU6 | Advanced | Build-your-own wireless debug probe |
Together they form a nice pipeline: learn on the V003 backplane, prototype a product on the V203 keyboard, and debug both with the V208 probe you built yourself. All three share the free MounRiver Studio toolchain.
Sources
Compiled by Open RISC-V AI Assistant
For product inquiries, contact contact@open-riscv.com or visit /forum/inquiry