An open source development environment (tooling, headers, examples) for the CH32V003 with gcc-riscv64 that can be used in Windows (Native), Linux and/or WSL. The CH32V003 is 10-cent part with a RISC-V EC core that runs at 48MHz, has 16kB of flash and 2kB of RAM and a bunch of peripherals. It also comes in SOP-8, QFN-20 and SOIC packages. You can get the datasheet here.

The goal of this project is to develop the tooling and environment for efficient use of the CH32V003. Avoid complicated HALs, and unleash the hardware! The existing EVT is massive, and dev environment weighty. This project specifically avoids the HAL and makes it so you can just use the TRM. In contrast, blinky is only 500 bytes with ch32v003fun, boots faster, and significantly simpler overall.

ch32v003fun contains:

1. Examples using ch32v003fun, but not as many as using the HAL.
2. "minichlink" which uses the WCH CH-Link with libusb, for cross-platform use.

• An STM32F042 Programmer, the NHC-Link042
• An ESP32S2 Programmer, the esp32s2-funprog
• The official WCH Link-E Programmer.
• Supports gdbserver-style-debugging for use with Visual Studio.
• Supports printf-over-single-wire. (At about 400kBaud)

3. An extra copy of libgcc so you can use unusual risc-v build chains, located in the misc/libgcc.a.
4. A folder named "ch32v003fun" containing a single self-contained source file and header file for compling apps for the ch32v003.
5. On some systems ability to "printf" back through
6. A demo bootloader.

In Progress:

1. Write more demos.

And by fast I mean very fast. Typically around 36kBytes/sec.

./minichlink -T | pv > /dev/null
Found ESP32S2 Programmer
 536KiB 0:00:15 [36.7KiB/s] [        <=>                     ]

You can just try out the debugprintf project, or call SetupDebugPrintf(); and printf() away.

Via gdbserver built into minichlink! It works with gdb-multiarch as well as in Visual Studio Code

For installation instructions, see the [https://github.com/cnlohr/ch32v003fun/wiki/Installation](wiki page here)

You can use the pre-compiled minichlink or go to minichlink dir and make it.

cd examples/blink
make

In Linux this will "just work"(TM) using minichlink.
In Windows, if you want to use minichlink, you will need to use Zadig to install WinUSB to the WCH-Link interface 0.
The generated .hex file is compatible with the official WCH flash tool.

text = code, data = constants and initialization values, bss = uninitialized values.
dec is the sum of the 3 and reflects the number of bytes in flash that will get taken up by the program.

It enumerates as 2 interfaces. 0. the programming interface. I can't get anything except the propreitary interface to work.

1. the built-in usb serial port. You can hook up UART D5=TX to RX and D6=RX to TX of the CH32V003 for printf/debugging, default speed is 115200. Both are optional, connect what you need.

If you want to mess with the programming code in Windows, you will have to install WinUSB to the interface 0. Then you can uninstall it in Device Manager under USB Devices.

On linux you find the serial port with ls -l /dev/ttyUSB* /dev/ttyACM* and connect to it with screen /dev/ttyACM0 115200
Disconnect with CTRL+a :quit.

Adding your user to these groups will remove the need to sudo for access to the serial port: debian-based sudo usermod -a -G dialout $USER arch-based sudo usermod -a -G uucp $USER

You'll need to log out and in to see the change.

To use the WCH-Link in WSL, it is required to "attach" the USB hardware on the Windows side to WSL. This is achieved using a tool called usbipd.

1. On windows side, install the following MSI https://github.com/dorssel/usbipd-win/releases
2. Install the WSL side client:
   • For Debian: sudo apt-get install usbip hwdata usbutils
   • For Arch-based: sudo pacman -S usbip hwdata usbutils
   • For Ubuntu (not tested):

        sudo apt install linux-tools-5.4.0-77-generic linux-tools-virtual hwdata usbutils
        sudo update-alternatives --install /usr/local/bin/usbip usbip `ls /usr/lib/linux-tools/*/usbip | tail -n1` 20

3. Plug in the WCH-Link to USB
4. Run Powershell as admin and use the usbipd list command to list all connected devices
5. Find the this device: 1a86:8010 WCH-Link (Interface 0) and note the busid it is attached to
6. In powershell, use the command usbipd wsl attach --busid=<BUSID> to attach the device at the busid from previous step
7. You will hear the windows sound for the USB device being removed (and silently attached to WSL instead)
8. In WSL, you will now be able to run lsusb and see that the SCH-Link is attached
9. For unknown reasons, you must run make under root access in order to connect to the programmer with minichlink. Recommend running sudo make when building and programming projects using WSL. This may work too (to be confirmed):

Unlike serial interfaces, by default, the USB device is owned by root, has group set to root and everyone else may only read by default. The way to allow non-root users/groups to be able to access devices is via udev rules.

minichlink provides a list of udev rules that allows any user in the plugdev group to be able to interact with the programmers it supports.

You can install and load the required udev rules for minichlink by executing the following commands in the root of this Git repository:

sudo cp minichlink/99-minichlink.rules /etc/udev/rules.d/
sudo udevadm control --reload-rules && sudo udevadm trigger

If you add support for another programmer in minichlink, you will need to add more rules here.

Note: This readme used to recommend manually making these rules under 80-USB_WCH-Link.rules. If you wish to use the new rules file shipped in this repo, you may want to remove the old rules file.

I wrote some libusb copies of some of the basic functionality from WCH-Link, so you can use the little programmer dongle they give you to program the ch32v003.

Currently, it ignores all the respone codes, except when querying the chip. But it's rather surprising how featured I could get in about 5 hours.

Anyone who wants to write a good/nice utility should probably look at the code in this folder.

Note: This is genearlly used for CI on this repo. However, note that this is not the path that allows for debugging on Windows.

This project can also be built, uploaded and debugged with VSCode and the PlatformIO extension. Simply clone and open this project in VSCode and have the PlatformIO extension installed.

See here for further details.

If the C/C++ language server clangd is unable to find ch32v003fun.h, the example will have to be wiped make clean and built once with bear -- make build, which will generate a compile_commands.json, which clangd uses to find the include paths specified in the makefiles.
make clangd does this in one step. build_all_clangd.sh does in build scripts does this for all examples.

• Needed for programming/debugging: SWIO is on PD1
• Optional (not needed, can be configured as output if fuse set): NRST is on PD7
• UART TX (optional) is on: PD5

You can open a github ticket or join my Discord in the #ch32v003fun channel. https://discord.gg/CCeyWyZ

• https://raw.githubusercontent.com/openwch/ch32v003/main/RISC-V%20QingKeV2%20Microprocessor%20Debug%20Manual.pdf Debugging Manual
• http://www.wch-ic.com/downloads/QingKeV2_Processor_Manual_PDF.html Processor Manual
• http://www.wch-ic.com/downloads/CH32V003RM_PDF.html Technical Reference Manual
• http://www.wch-ic.com/downloads/CH32V003DS0_PDF.html Datasheet
• https://github.com/CaiB/CH32V003-Architecture-Exploration/blob/main/InstructionTypes.md Details for the compressed ISA on this chip.