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@@ -2,38 +2,117 @@ ## Background -The CH573F is a relatively new, little micro controller powered off a 32-bit -Risc-V core. It's a Chinese board with tenuous support with existing -infrastructure, but they are dirt-cheap on Ali Express with -not-impossible-to-read documentation. This makes it prime real-estate for some -bare-metal hacking. One can find them [here](https://www.aliexpress.us/item/3256804723616466.html). +THe CH573F is a relatively new, fairly powerful, little microcontroller. They're +about USD 1.00 a piece on AliExpress, which makes them incredibly cheap for +their abilities, which makes them an ideal replacement for my Arduinos to run my +Christmas lights! + +The documentation for the controller is fairly easy to read, though examples are +few and far between and the SDK is mostly in Chinese, but that's what this +project is for. True to form, this project has no dependencies on any 3rd party +SDK or OS. It's completely bare metal from the ground up. + +## Specs + +The CH573 has some pretty impressive specs for its price point. For the purposes +of this project, it has: + +* Royalty-free RISC-V core: + * 32-bit Qingke RISC-V processor WCH RISC-V3A + * RV32IMAC instruction set w/ hardware multiplication and division. + * System frequency from 32KHz up to 60MHz (Though I can only get 6.4MHz, 30MHz + and 60MHz to work). +* 512K FlashROM + * 32KB application data +* UART + * 4 independent UART, with 8-level FIFO +* SPI support with DMA + +## Related Work + +This project is very similar to: + + * https://git.josher.dev/cgit/stm32l4.git/ + * https://git.josher.dev/cgit/esp32-ws2812b.git/ + +Together they make up my microcontroller trio for my Christmas lights every +year. ## Setup -To compile this project, one needs a riscv32 cross compiler. These can be built -with ct-ng. Describing this processes is outside the scope of this document, but it -can be done. +To compile this project, one needs a few things. + +1. A RISC-V crosscompiler with Picolibc +1. An installed version of "Fiddle", which is my custom + register-description-language, found at https://git.josher.dev/cgit/fiddle.git +1. ch-flash, or another WCH ISP. +1. Cmake + +### RISC-V Cross-compiler with Piclibc + +The easiest way to get one of these is to use +[crosstool-ng](https://crosstool-ng.github.io/) with the default +`riscv32-picolibc-elf` + +```bash + $ ct-ng riscv32-picolibc-elf + $ ct-ng build + $ ct-ng install +``` + +### Fiddle + +Fiddle is a program used to take language-agnostic register descriptions and +compile them into usable source code. The register descriptions for this project +are provided as fiddle (fdl) files. + +The Fiddle compiler is implemented in Haskell using the Haskell stack build +system. Install stack with: + +```bash + $ apt install stack +``` + +get fiddle: + +```bash + $ git clone https://git.josher.dev/cgit/fiddle.git + $ cd fiddle + $ stack install +``` + +This will compile and install `fiddlec`, which is required to build this +project. -You should then have a cross-compiler with a tuple like -`riscv32-arm-unknown-elf`, which is the tuple this project expects. +### WCH ISP -## Compilation +There are many open source projects which can flash to the CH573F. I have one in +my git grove, but they're easy to find if another one works better. -To compile, just run make. There are no build dependencies at the moment. +```bash + $ git clone https://git.josher.dev/cgit/ch-flash.git + $ cd ch-flash + $ make +``` -## Flashing +### CMake -Flashing this project is more difficult as the offical method for flashing uses -proprietary-garbage. Luckily there's an open-source solution at -https://github.com/frank-zago/isp55e0. So one needs to build that project and -flash using it. +Install cmake through your package manager. -The board can be fickle at times, but I got the flashing procedure down consistently. +```bash + $ apt install cmake +``` -To flash you, +## Compiling and Flashing -1. Disconnect the board from the USB -2. Hold the BOOT button, and plug the board back in (while stil holding BOOT!) -3. run `make flash` (Still hold BOOT!) +```bash + $ git clone https://git.josher.dev/ch573.git + $ cd ch573 + $ cmake -B build + $ make -C build + $ /path/to/ch-flash -f build/main.bin +``` -once make flash is complete, the board should immediately reset and start blinking. +To flash, disconnect the ch573 from USB, hold down the BOOT button, then +re-connect it, ch-flash should automatically detect it and flash it. After that, +it all should work. |