ch32fun

2 Articles

10 Cent Microcontroller Makes Tracker Music

October 29, 2025 by 17 Comments

We are absurdly spoiled these days by our microcontrollers. Take the CH32V00X family– they’ve been immortalized by meme as “the ten cent micro” but with a clock speed of 48MHz and 32-bit registers to work with, they’re astoundingly capable machines even by the standards of home computers of yore. That’s what motivated [Tim] to see if he could use one to play MOD files, with only minimal extra parts– and quite specifically no DAC.

Well, that’s part of what motivated him. The other part was seeing Hackaday feature someone use a CH32V003 making chiptune-like beeps. [Tim] apparently saw that post as a gauntlet thrown down, and he picked it up with an even smaller chip: the CH32V002, which he proceeded to turn into a MOD player. For those of you who slept through 80s and early 90s (or for those precocious infants reading this who hadn’t then yet been born), MOD files are an  electronic music format, pioneered on the Amiga home computers. Like MIDI, the file specifies when to play specific voices rather than encoding the sound directly. Unlike MIDI, MOD files are self-contained, with the samples/voices used being stored inside the file. The original version targeted four-channel sound, and that’s what [Tim] is using here.

As you can see from the demo video, it sounds great. He pulled it off by using the chip’s built-in PWM timer. Since the timer’s duty cycle is determined by a variable that can be changed by DMA, the CPU doesn’t end up with very much to do here. In the worst case, with everything in flash memory instead of SRAM, the CPU is only taxed at 24%, so there’s plenty of power to say, add graphics for a proper demo. Using the existing MODPlay Library, [Tim]’s player fits into 4kB of memory, leaving a perfectly-usable 12kB for the MOD file. As far as external components needed, it’s just an RC filter to get rid of PWM noise.

[Tim] has put his code up on GitHub for anyone interested, and has perhaps inadvertently cast down another gauntlet for anyone who wants to use these little RISC V microprocessors for musical tasks. If you can do better, please do, let us know.

Continue reading “10 Cent Microcontroller Makes Tracker Music” →

World’s Cheapest ARM Debugger Is Actually RISC-V

October 22, 2025 by 18 Comments

[bogdanthegeek] has a lot of experience with the ARM platform, and their latest escapade into working with cheap ARM chips recovered from disposable vapes involved a realization that it was just plain wrong to debug such recovered silicon with something as expensive as a Pi Pico. No, they needed to build a debugger using the super cheap CH32V003.

What follows is an interesting tour around ARM Debug Access Port (DAP) programmers and creating a practical USB-connected device that actually works with modern toolchains. The first problem to be solved was that of host connectivity. These days, it’s USB or go home, which immediately limits the microcontrollers you can choose. Luckily for [Bogdan], they were aware of the excellent work by [cnlohr] on wedging low-speed USB support onto the RISC-V CH32v003 with the software-only bit-banging rv003usb, which provided a starting point. The next issue was to check for interrupt-driven endpoint support (needed for low-speed USB) in the Mac OS X kernel, which they knew was being dropped at an alarming rate (well, at least for full-speed). Luckily, the CMSIS-DAP standard required support for interrupt-driven USB endpoints, so kernel support was likely intact.

Next, [Bogdan] noticed that the DAPLink project had been ported to the bigger, native-USB WCH chips like the CH32V203, so it was a matter of porting this code to the diminutive CH32V003 using the rv003usb stack for the USB support using [cnlohr]’s ch32fun toolchain. There were a few bumps along the way with a lack of clarity in the DAPLink code, and some inconsistencies (across platforms) with the USB library dependencies of the upstream tool pyOCD, but they did get some tools working on at least Mac OS and some others on Linux. Which was nice.

We’ve covered the CH32V003 a fair bit, with people trying to give it all kinds of big-CPU tricks, such as speech recognition (of sorts) or even building a supercluster.