LinkW: Open Source Wireless Programmer Based on CH32V208

LinkW is an open-source wireless debug probe built around the WCH CH32V208 RISC-V MCU. It targets the common frustration of dragging a USB cable to a target board during bring-up: the probe pairs over wireless, exposes a CMSIS-DAP interface, and provides a UART pass-through for printf-style debugging. The project is published on OSHWHUB with full schematic, PCB, BOM, and a step-by-step firmware flashing guide.

What It Does

• Wireless debug and download for WCH RISC-V MCUs
• Compatible with SWD/JTAG targets, including ARM Cortex-M devices
• One UART channel for serial output
• Replicates the WCH-Link experience without the physical cable between host and target

Hardware Highlights

• MCU: CH32V208GBU6 (QFN28, 4 x 4 mm)
• Wireless: 2.4 GHz on-chip radio through CH32V208
• Power: XC6206P332MR 3.3 V LDO
• Protection: two CH217K current-limiting chips for short-circuit protection
• Connector: 2 x 5 pin header for SWD/JTAG/UART/GND/VCC
• Power options: USB-A or 5 V pin on the debug connector

The author intentionally added a 5 V input on the debug connector so the probe can be powered from the target side when used as a wireless dongle, removing the need for a second USB cable.

Firmware Setup

The project uses standard WCH tools:

• WCHISPTool — for firmware download
• WCH-LinkUtility — for wireless address pairing and mode configuration
• MounRiver Studio — for driver installation (the LinkDrv folder in older MRS versions contains the probe drivers)

Typical flashing workflow:

1. Hold the BOOT button while plugging the probe into USB.
2. Check Device Manager for a USB Module device; this confirms the bootloader is reachable.
3. Use WCHISPTool with either USB or UART interface to load the LinkW firmware from the Firmware_Link folder inside WCH-LinkUtility.
4. Release BOOT after the download completes.

Wireless Pairing

After flashing, open WCH-LinkUtility:

1. Select RISC-V architecture and WIN-USB mode. WIN-USB mode exposes CMSIS-DAP, which is what Keil and most IDEs expect.
2. Set the target MCU family to CH32V208.
3. Read the default wireless address from one module and write the same address into the second module so the pair shares one network ID.
4. Verify both modules show the same address.

In the target IDE, choose CMSIS-DAP as the debugger. Power on the target-side module first, then the host-side module. The CON LED stays solid blue in WIN-USB mode, and the Mode LED turns green once the wireless link is established.

Use Cases

• Firmware development on devices mounted inside enclosures or on moving parts
• Remote debugging of battery-powered nodes
• Shared lab benches where multiple developers need to access the same target without swapping cables
• Teaching environments where students can debug targets from their own laptops without physical access to the board

The CH32V208 was a good fit here: it is a RISC-V MCU with integrated BLE/2.4 GHz radio, plenty of GPIO for the SWD/JTAG/UART signals, and a price point that keeps the probe cheap enough to leave on the target.

Project Files

• Schematic and PCB: available in the OSHWHUB editor
• BOM: LCSC-compatible, with CH32V208GBU6 as the single IC cost driver
• License: GPL 3.0
• Estimated reproduction cost: around 10 RMB

If you are building projects with CH32V003, CH32V203, CH32V307, or CH32V317 and want a cordless debug experience, this probe is worth replicating.

Source: 无线烧录器（LinkW）——CH32V208 (OSHWHub) https://oshwhub.com/yzh5256/wu-xian-shao-lu-qi-ch32v208

CH32V003 入门建议

CH32V003 是南京沁恒的 RV32EC 入门级 MCU，主频 48MHz，片上 2KB SRAM + 16KB Flash（部分型号），价格约 $0.1，非常适合 RISC-V 入门和成本敏感场景。

1. 开发环境

推荐使用 MounRiver Studio（基于 Eclipse 的官方 IDE），内置 GCC + OpenOCD 调试。

2. 最简 GPIO 闪烁代码

#include "ch32v00x.h"

int main(void) { GPIO_InitTypeDef gpio = {0}; RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOC, ENABLE); gpio.GPIO_Pin = GPIO_Pin_0; gpio.GPIO_Mode = GPIO_Mode_Out_PP; gpio.GPIO_Speed = GPIO_Speed_50MHz; GPIO_Init(GPIOC, &gpio); while (1) { GPIO_WriteBit(GPIOC, GPIO_Pin_0, Bit_SET); for (volatile int i = 0; i < 80000; i++); GPIO_WriteBit(GPIOC, GPIO_Pin_0, Bit_RESET); for (volatile int i = 0; i < 80000; i++); } }

3. 调试 / 烧录

• 使用 WCH-Link（便宜，淘宝 ¥15 左右）
• 或 DAP-Link / JLink OB
• 烧录接口：SWD（2 线）

4. 常用外设

GPIO、USART、I2C、SPI、TIM（PWM）、ADC（10-bit）、看门狗，基本覆盖教学 / 简单控制需求。

如果要做 BLE，请升级到 CH32V208；如果需要以太网，请考虑 CH32V307。 如有更多问题，欢迎在论坛继续讨论或联系 contact@open-riscv.com

Thanks for posting the LinkW reference. We also saw the same wireless programmer project on LCSC EDA (oshwhub.com/yzh5256) and wanted to add a few practical notes for anyone trying to replicate it on CH32V208WBU6 or CH32V208GBU6. Configuration observations from the original LCSC project (yzh5256):

• Use WCH-LinkUtility to set the Link into WIN-USB mode first, otherwise Keil will not see the device.
• Match the 32-bit wireless address between master and slave (default E339E339 must be changed to identical values like 3578B69C).
• The BOOT key must be held while plugging in the USB cable to enter DFU mode for WCHISPTool flashing.
• For RISC-V targets only the WinUSB / CMSIS-DAP mode works for debugging through LinkW; the LinkRV mode is reserved for non-debug use cases.
• After RISC-V mode is enabled, there is a known issue with some early firmware revisions where the green Mode LED is wired to a GPIO that drives the orange LED instead - the design fix is in V1.0.3.

For open-riscv.com community members who bought CH32V208 samples, we can ship LinkW bare PCBs in a kit form. Just reply here if you want a batch quote.

Source: https://oshwhub.com/yzh5256/wu-xian-shao-lu-qi-ch32v208