# CLAUDE.md

This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.

## Context

University exercise (RTO, "UE u01") for an STM32F072VBTx (Cortex-M0) board. The git root is two levels up (`rto1/`); `UE/` holds exercises, `VO/` holds lecture slides (PDF). The exercise spec is [doc/u01.pdf](doc/u01.pdf). Code comments are partly German.

## Build

Keil µVision 5 project [Apus.uvprojx](Apus.uvprojx), target `Apus`, ARM Compiler 6 (armclang V6.23). There is no Makefile, linter, or test suite. Command-line build:

```
"C:/Users/gaems/AppData/Local/Keil_v5/UV4/UV4.exe" -b Apus.uvprojx -j0 -o build_log.txt
```

(`-r` for rebuild, `-f` to flash.) Output goes to `output/` (`Apus.axf`, `Apus.build_log.htm`), map file to `listing/`. These build artifacts and the `.uvguix.*` / `.uvoptx` IDE state files are committed to git, so they show up as modified after every build.

- Global defines: `STM32F072,USE_STDPERIPH_DRIVER`. Include paths: `src`, `stm32f0-stdperiph`, `src/Devices`, `src/Tasks` — so BSP headers are included as `"BSP/Led.h"`, task headers directly.
- **New `.c` files must be added to the project's file groups in `Apus.uvprojx`** (or via the µVision IDE), otherwise they are not compiled.

## Architecture

- **Superloop, no RTOS (yet).** [src/main.c](src/main.c) initializes the BSP, then calls each task function (`TaskCounter`, `TaskKey`, `TaskLed`, `TaskWatch`, `TaskPoti`, `TaskMandelbrot`) once per loop iteration, clearing the TFT at the start of each iteration. Tasks are plain `void TaskX(void)` functions in [src/Tasks/](src/Tasks/) (aggregated by `TaskAll.h`) that keep state in `static` locals and draw their own row on the TFT (`Tft_DrawString(10, 18 + row*24, ...)`, 16x24 font).
- **Timing measurement via GPIO.** [src/Debug.c](src/Debug.c) drives GPIOB pins as logic-analyzer probes; `debug_t` maps each task (and the SysTick ISR) to a pin. `main.c` wraps every task call in `Debug_Set`/`Debug_Unset`; the double toggle on the `mandelbrot` pin at loop start measures the probe overhead. When adding a task, add an enum entry in `Debug.h` **and** its pin to the mask in `Debug_Init`.
- **SysTick** ([src/BSP/systick.c](src/BSP/systick.c)) fires every 1 ms and increments a private `msTicks` counter (also toggles the `systick` debug pin).
- **BSP** ([src/BSP/](src/BSP/)): `Key`, `Led`, `Adc` (potentiometer), `TftDisplay` — thin wrappers over the vendored ST Standard Peripheral Library in [stm32f0-stdperiph/](stm32f0-stdperiph/). Device/CMSIS/startup files live in [src/Devices/](src/Devices/). Don't modify vendored code.
- [src/StdDef.h](src/StdDef.h) provides `BOOL`/`TRUE`/`FALSE`/`NULL_PTR`; use these instead of `<stdbool.h>`. `assert()` failures land in `__aeabi_assert` in `main.c` (infinite loop for inspection in the debugger).