BadHAL

A Hobby-grade HAL/BSP for the STM32-H750-disco board.

TODO

• Tune memory timings
• Doom
• Ethernet + network stack
• UDP pixelflut
• Build a pixelflut wall @ DCTF27 or something.

BSP features

• System clock setup (480MHz + QSPI + LTDC)
• Setup for external SDRAM (8 MiB @ 0x9000_0000)
• Header only include fault handlers (crash.h)

HAL Drivers

• usart (blocking only for now)
• nvic
• clock (subset of RCC; work in progress)
• mpu
• gpio
• debug (SWO logging)
• qspi
• ltdc

Libraries

• badfs (a simple read-only filesystem for QSPI flash)
• text (a simple text rendering library for LTDC)
• sprintf (stb_sprintf)

Other features

• SysTick and sys_delay
• FPU setup
• I-Cache, D-Cache and branch predictor setup
• C23 only codebase with a couple intrinsics

Building

On Arch Linux (btw) you can grab all deps by doing

sudo pacman -Syu --needed \
    cmake \
    arm-none-eabi-gcc \
    arm-none-eabi-gdb \
    arm-none-eabi-newlib \
    arm-none-eabi-binutils \
    stlink

If targeting clang also grab clang, lld, and baremetal-compiler-rt(AUR).

Otherwise hunt down these deps for your system of choice. Make sure your compiler is new enough for C23

Then you can setup the project by doing

cmake -G Ninja -B build -DCMAKE_BUILD_TYPE=Release

# you can also set:
# -DGCC_PREFIX="/path/to/your/gcc/arm-none-eabi"
# -- or --
# -DUSE_CLANG=ON
# -DCLANG_PATH="/path/to/folder/containing/clang/"
# -DCLANG_RTLIB_PATH="/dir/libclang_rt.builtins-armv7em.a"

And then build and flash with

cd build
ninja burn # has build as a dependency

Debugging

The project is setup for VSCode debugging with Cortex-Debug. Pressing F5 should start a debug session.

Make sure you rebuild and flash before debugging.

Docs / learning

You should check the following docs in order from most to least specific:

• UM2488 - Discovery kit manual (pinout, names other components on board)
• Discovery board schematics (very specific part numbers)
• STM32H750xB datasheet (contains GPIO AF table)
• RM0433 - STM32H7 series manual (documents most peripherals, memory map)
• ARM Cortex-M7 manual (MPU, FPU, NVIC...)
• ARMv7-M Architecture Reference Manual (ISA, SCB, ...)

There are also the specific manuals for the DK components:

• LCD datasheet
• Flash datasheet

Shoutout:

• iKramp/stm32-project (Good place to "borrow" some code)