As its name implies, at the heart of this board made by nanodyne, features the cost-effective CH32V003F4U6 microcontroller by WCH, boasting a clock frequency of up to 48 MHz, 16KB of Flash memory, and 2KB of RAM.

CH32V003 USB PCB design
(click image to enlarge)

The board comes with an external crystal pre-installed, but it can be readily removed and bypassed with a solder bridge, offering flexibility in clock configuration to suit users’ specific needs.

There are 13 (or 15 when considering crystal pins) of the 18 GPIOs directly accessible from the side pins. Additionally, there is a user LED at PC0 and a user button at PD7, which also serves a reset functionality.

CH32V003 USB bottom view
(click image to enlarge)

The product page emphasizes the board’s capacity to utilize bitbanged USB with the rv003usb stack by CNLohr, making it an ideal plug-and-play platform for USB peripheral applications. Additionally, three of the 18 available GPIOs are designated for USB functionality, with accessible USB data lines via two through-holes on the board’s interior.

The product page mentions that the board is fully compatible with the open-source ch32v003fun project. Furthermore, the PCB design is open source with the CERN-OHL-W-2.0 license and available on GitHub

CH32V003 USB top view
(click image to enlarge)

To program the board, users require a compatible SWIO programmer, such as the WCH LinkE. Alternatively, users can utilize other programmers, like the ESP32-S2, as described in the documentation. 

Lastly, Arduino enthusiasts can utilize the Ardulink project to program the board with an AVR-based ATMega328P device (i.e. Uno R3, Nano, etc).

 Further information

The CH32V003 USB Development Board is primarily intended for development and evaluation purposes. It is priced at $5.16 for a single unit, with volume discounts available; for instance, two units cost $5.58, three units cost $6.42, and so on.