CH32V003 Tristate Multiplexing LED

# CH32V003 Tristate Multiplexing LED CH32V003J4M6 (SOP-8) drives a 5x6 LED matrix with only 6 GPIOs. - GitHub: [https://github.com/limingjie/CH32V003-Tristate-Multiplexing-LED](https://github.com/limingjie/CH32V003-Tristate-Multiplexing-LED) - YouTube: [LED Chaser Terminator - Low-Cost CH32V003 MCU Drives a 5x6 LED Matrix with 6 GPIOs - 555 Timer RIP!](https://www.youtube.com/watch?v=1Sye0EghZRU) - Bilibili: [Ultra Low-Cost LED Chaser - 6 GPIOs Drive a 5x6 LED Matrix](https://www.bilibili.com/video/BV1tz4y1g7z6/) I programmed 5 boards to show running words. But as there is no synchronization among the boards, the boards will soon run out of sync. ## How it works The program uses the [Tristate Multiplexing (Charlieplexing)](https://en.wikipedia.org/wiki/Charlieplexing) technique to drive LEDs. Each GPIO is used as both row and column lines, so n GPIOs support `n x (n - 1)` LEDs. There is only one LED light at a time, and each LED supports 16 brightness levels. The program uses `SysTick` to update the LED matrix 50,000 times per second, so each LED updates at 50,000/30/16 = 104Hz, which is fast enough for human eyes to notice. ## Programming To program the CH32V003 microcontroller, you will need a programmer that supports SWD. - The official [WCH-LinkE](https://www.wch-ic.com/products/WCH-Link.html) programmer. - Check [CNLohr's ch32v003fun](https://github.com/cnlohr/ch32v003fun) project for other options, such as ESP32S2 and Arduino-based programmers. ## Compiling and Uploading (macOS) Install [RISC-V Toolchain](https://github.com/riscv-software-src/homebrew-riscv). ```shell brew tap riscv-software-src/riscv brew install riscv-tools ``` This project uses the `minichlink` utility to upload, so the `libusb` is required as a dependency. ```shell brew install libusb ``` Clone the project, connect the board to the programmer, then run the `make` command to compile and upload the firmware. ```shell git clone https://github.com/limingjie/CH32V003-Tristate-Multiplexing-LED.git cd CH32V003-Tristate-Multiplexing-LED make ``` ## Build `minichlink` Utility (macOS) The `minichlink` utility in the `tools` library is built for `x86_64`. If your macOS runs on Apple Silicon, you can build the `minichlink` utility and copy it to the [tools](https://github.com/limingjie/CH32V003-Tristate-Multiplexing-LED/tree/main/tools) folder. ```shell brew install pkg-config brew install libusb git clone https://github.com/cnlohr/ch32v003fun.git cd ch32v003fun/minichlink make ``` ## References * [Stefan Wagner: CH32V003 RISC-V Mini Game Console](https://github.com/wagiminator/CH32V003-GameConsole) * [CNLohr: ch32v003fun](https://github.com/cnlohr/ch32v003fun) * [Stefan Wagner: TinyProbe - Logic Probe based on ATtiny13A](https://github.com/wagiminator/ATtiny13-TinyProbe) * [David Johnson-Davies: Twelve PWM Outputs from an ATtiny85](http://www.technoblogy.com/show?2H0K) * [Wikipedia: Charlieplexing](https://en.wikipedia.org/wiki/Charlieplexing)