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+<!-- SPDX-License-Identifier: MIT -->
+# CH32V003 ch32fun template (fully open source)
+
+A minimal `make` project for the CH32V003 built on
+[ch32fun](https://github.com/cnlohr/ch32fun) (MIT). It uses no WCH EVT SDK,
+no WCH GCC, no `libprintf`, and no IQmath.
+
+The example blinks an LED on `PD0`. Put your own application in `firmware.c`.
+
+## Stack
+
+| Component | Role | License |
+|---|---|---|
+| ch32fun | startup, headers, GPIO helpers, `printf`, linker script | MIT |
+| `riscv64-elf-gcc` / binutils | compiler and binutils | GPL |
+| `riscv64-elf-newlib` | **headers only** (`stdio.h`, `string.h`, ...) | BSD |
+| `ch32fun/misc/libgcc.a` | compiler runtime | GCC runtime license |
+| `minichlink` | flashing / SWIO monitor | MIT |
+| `wchisp` (optional) | alternative flasher | GPL-2.0 |
+
+### Why the missing `rv32ec` newlib multilib does not matter
+
+Arch's `riscv64-elf-newlib` has no `rv32ec`/`ilp32e` library, but ch32fun
+builds with `-nostdlib` and links its own `misc/libgcc.a`:
+
+```text
+-nostdlib ... -L.../misc -lgcc
+```
+
+Only newlib's **headers** are used. The CH32V003 startup, `printf`, and
+runtime support come from ch32fun, so no WCH or newlib object code is linked.
+
+## Requirements
+
+Arch packages:
+
+```bash
+sudo pacman -S --needed base-devel riscv64-elf-gcc riscv64-elf-newlib libusb
+```
+
+`libusb` is only needed to build `minichlink` for flashing. `systemd-libs`
+provides `libudev` and is normally already installed.
+
+ch32fun checkout:
+
+```bash
+git clone https://github.com/cnlohr/ch32fun ~/code/ch32fun
+```
+
+The Makefile defaults to `~/code/ch32fun`. If yours is elsewhere:
+
+```bash
+make CH32FUN_ROOT=/path/to/ch32fun
+```
+
+It also defaults to the Arch newlib header directory
+`/usr/riscv64-elf/include` and the compiler prefix `riscv64-elf`. Override
+with `NEWLIB=...` or `PREFIX=...` if needed.
+
+## Build
+
+```bash
+cd ch32fun-template
+make
+make size
+```
+
+Outputs:
+
+```text
+firmware.elf
+firmware.bin
+firmware.hex
+firmware.lst
+firmware.map
+```
+
+Only `firmware.bin` is written to the chip. `make` never flashes implicitly.
+
+The template currently builds to about 620 bytes of flash:
+
+```text
+text    data    bss    dec    hex
+620       0      0    620    26c    firmware.elf
+```
+
+## Flash and monitor
+
+`make flash` builds `minichlink` on first use and writes `firmware.bin`:
+
+```bash
+make flash
+```
+
+`minichlink` needs permission to access the WCH-Link. Install its udev rules
+once:
+
+```bash
+sudo make -C ~/code/ch32fun/minichlink install_udev_rules
+```
+
+Then reconnect the WCH-LinkE. Wiring for SWIO programming:
+
+```text
+WCH-LinkE       CH32V003
+3V3      <-->   3V3
+GND      <-->   GND
+SWIO     <-->   PD1
+```
+
+View `printf` output over the SWIO debug channel:
+
+```bash
+make monitor
+```
+
+`make terminal` and `make unbrick` are also provided by ch32fun's build rules.
+
+If you prefer `wchisp` from the AUR:
+
+```bash
+yay -S wchisp
+wchisp flash firmware.bin
+```
+
+## Customize
+
+- `firmware.c` — application code; `LED_PIN` is `PD0`.
+- `funconfig.h` — clock and `printf` configuration.
+- `TARGET` — output basename. It must match the application source name, so
+  `TARGET := firmware` uses `firmware.c`.
+- `TARGET_MCU` — defaults to `CH32V003`; change it to target another ch32fun
+  MCU.
+
+Useful overrides:
+
+```bash
+make TARGET_MCU=CH32V003
+make CH32FUN_ROOT=/path/to/ch32fun
+make PREFIX=riscv32-unknown-elf
+make clean
+```
+
+For a Linux-hosted cross compiler instead of the bare-metal package:
+
+```bash
+make PREFIX=riscv64-linux-gnu EXTRA_CFLAGS=-no-pie
+```
+
+That path also works but is less clean; `riscv64-elf-gcc` is recommended.
+
+## License
+
+The template files (`Makefile`, `firmware.c`, `funconfig.h`, this README) are
+MIT-licensed; see `LICENSE`. ch32fun is MIT-licensed. GCC, binutils, newlib,
+and `minichlink` are open source under their respective licenses.