# nanji

An experimental OS for the PineTime.

nanji aims to be dependency-free project, handling everything from bootstraping the hardware to the UX.
Thus, it will not rely on any third party bootloader or external RTOS.

This is a hobby project to play around OS development.
As such, it is by no way intended to be daily-driven by anyone.

Moreover, I don't even recommend to flash it on any other hardware than the PineTime dev kit wired to a STLink-V2 interface.

nanji is written in C99 for to be buildable with most compilers.
Moreover, as much as I would like to use C23, its new features are still not all implemented by GCC for the `arm-none-eabi` target.

## Building and flashing

Build-time dependencies:
- GCC cross-compiler (>= 15) and binutils for the `arm-none-eabi` target
- Make
- OpenOCD to flash to the PineTime.

To build nanji, you can just run `make` at the project root.
The resulting binary will be found at `build/nanji`.

Connect your PineTime to your machine through a STLink-V2 interface.
If you don't know how to do so, please read the [PineTime Devkit Wiring](https://wiki.pine64.org/wiki/PineTime_Devkit_Wiring) guide on the Pine64 wiki.

Once your pinetime is plugged to your PC through STLink-V2, start OpenOCD with:

```sh
openocd -f /usr/share/openocd/scripts/interface/stlink.cfg -f /usr/share/openocd/scripts/target/nrf52.cfg
```

You can then connect to the OpenOCD console through telnet or tcl on another shell, and run:
```
halt
nrf5 mass_erase
program <PATH_TO_THE_NANJI_BINARY>
```

## License

This project is licensed under the GPLv3.
See the `LICENSE` file.