Curious Scientist Walks Through the Design of a Sub-$5 WCH Electronics CH32V006K Dev Board

Pseudonymous maker "Curious Scientist" has shown off the design process for a compact, breadboard-friendly development board built around the WCH Electronics CH32V006K8U6 RISC-V chip — bringing the finished device to life for under $5.

"I have been working with the [WCH Electronics] CH32 microcontroller chips for a while, and I even designed some simple circuits with them such as my miniature breadboard voltmeter or my USB PD [Power Delivery] breadboard power supply," Curious Scientist explains. "This time, I picked a little more advanced microcontroller and designed a development board around it. I think it is particularly useful because, apart from the manufacturer's development board, there are no easy-to-buy designs available, according to my research."

While picking up WCH Electronics' official evaluation board is certainly an option, Curious Scientist found it came with too many drawbacks — in particular the fact that it can't be easily used with a breadboard unless you connect the two with a mess of flying wires. The solution: designing a new board built around the same part that uses a dual in-line 0.1"-spaced layout and can, as a result, simply be inserted directly into a breadboard.

The WCH CH32V006K8U6 itself is a low-cost 32-bit microcontroller built around the free and open source RISC-V instruction set architecture, delivering a single microcontroller core running at 48MHz, 8kB of static RAM (SRAM), and 62kB of program flash plus 3,328b for a bootloader. General-purpose input/output (GPIO) pins, including some linked to the part's 12-bit analog to digital converter (ADC), are brought out to 0.1" breadboard-friendly pin headers at either side of the board, plus a debug/programming header at one end.

Despite being designed for as low a production cost as possible, the finished board includes some handy features — such as a USB Type-C port, connected via a low-cost WCH Electronics CH340N USB-UART bridge, plus a Serial-Wire Debug (SWD) interface. It's this latter that is used to flash a program onto the CH32V006K8U6's internal program memory: "My board cannot be [programmed via USB], Curious Scientist admits. "At least, I haven't investigated the possibilities of it yet. I use the 1-wire debug interface (SWIO) for programming the CH32 microcontroller."

The project is documented on Curious Scientist's website, and in the video embedded above and on the maker's YouTube channel. The board design, created in KiCad 9, has been released on PCBWay under the reciprocal Creative Commons Attribution-ShareAlike license.