How to program a CH32V003 MCU without using WCH link

Question

I recently came across the CH32V003 MCU and wanted to embed it in my projects. To program, I was advised to use the WCH link but my standard port I use to program the MCUs is an USB port. So if I need to use it as a fixed model without using a separate programming device. When I browsed through YouTube, I found a channel 'Bitluni's lab'; I found that he made the supercluster and used a CH32V203 to program all the 16 CH32V003s, see Cheap Risc-V Supercluster for $2 (DIY, CH32V003).

Unfortunately, he didn't give any schematics and firmware. Is there any way like using a USB to one wire interface chip or using the same chip used in the WCH-link? If I need to use the same chip in the WCH-link, how to program that MCU?

Answer 1

One answer is to use CNLohr's project to bit-bang low speed USB on the CH32V003. I haven't quite gotten it compiling and working, but will report back if I run into any issues. Here is the current location of the codebase [1] and his reference PCB design [2] that he shows in his demo video (https://youtu.be/j-QazXghkLY).

Note that you still need to do the initial programming with a WCH-linkE, but after that you can supposedly use USB only.

[1] https://github.com/cnlohr/rv003usb, it will supposedly get integrated back into ch32v003fun

[2] https://github.com/cnlohr/cnhardware/tree/master/ch32v003/ch32v003f4u6_with_wsleds