STM32F746G-DISCO Windy Display

Live weather map for the STM32F746G-DISCO evaluation board, rendered on the onboard 480×272 TFT LCD. Inspired by Windy.com.

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What it shows

A Windy-style weather map centred on 56.460 °N, 13.592 °E (Scania, southern Sweden):

Element	Source
Map tiles	OpenStreetMap (zoom 9)
Current conditions (T, wind, humidity)	Open-Meteo free API
24-hour wind / gust chart	Open-Meteo hourly forecast
Wind-speed colour ramp	Windy.com palette

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Hardware

MCU	STM32F746NG, Cortex-M7 @ 216 MHz
Display	RK043FN48H-CT672B, 480×272, parallel RGB565
Display controller	LTDC (on-chip)
Pixel clock	~9.6 MHz via PLLSAI
SDRAM	IS42S32400F, 8 MB @ 0xC000_0000 (FMC)

Note – The weather image lives in Flash as a const uint16_t[] array. The LTDC AHB master reads Flash directly; no SDRAM copy is needed. SDRAM is initialised but not used for the static display.

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Repository layout

.
├── Core/
│   ├── Inc/
│   │   ├── main.h
│   │   ├── sdram.h
│   │   ├── stm32f7xx_hal_conf.h
│   │   ├── windy_display.h
│   │   └── windy_img.h          ← auto-generated (not in git, see below)
│   └── Src/
│       ├── main.c               ← boot + clock config
│       ├── sdram.c              ← FMC / IS42S32400F init
│       ├── stm32f7xx_it.c       ← SysTick handler
│       └── windy_display.c      ← LTDC init, points at windy_img[]
├── display_test.c / .h          ← standalone display test patterns
├── startup_stm32f746xx.s        ← Cortex-M7 vector table + Reset_Handler
├── STM32F746NGHx_FLASH.ld       ← linker script
├── Makefile
├── flash.sh                     ← GDB/OpenOCD flash helper
└── tools/
    ├── windy_render.py          ← renders weather map → windy_img.h
    └── requirements.txt

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Quick start

1 – Clone + submodules

git clone https://github.com/MYBLtd/746Disco_Windy.git
cd 746Disco_Windy
git submodule update --init --depth 1

This pulls two submodules into Drivers/:

• Drivers/STM32F7xx_HAL_Driver — STM32F7 HAL driver
• Drivers/CMSIS/Device/ST/STM32F7xx — CMSIS device headers

The ARM CMSIS core headers (core_cm7.h etc.) are vendored directly in Drivers/CMSIS/Include/ and require no separate download.

2 – Render the weather image

pip3 install -r tools/requirements.txt
python3 tools/windy_render.py
# → Core/Inc/windy_img.h  (auto-generated C header, ~1 MB source)
# → tools/windy_480x272.png  (preview)

3 – Build

make
# Optional: override STM32CubeF7 path
make CUBE_F7_PATH=/path/to/your/STM32CubeF7

4 – Flash

# Using st-flash (st-link):
st-flash write build/display_test.bin 0x08000000

# Or using the included GDB script (OpenOCD on port 3333):
./flash.sh

5 – Refresh the image

The image is a static snapshot baked into firmware. To update it:

python3 tools/windy_render.py   # fetch fresh weather data
make
st-flash write build/display_test.bin 0x08000000

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Toolchain

• arm-none-eabi-gcc ≥ 12 (tested with 14.2.1)
• Python 3.10+ with requests, Pillow, numpy
• st-flash or OpenOCD for flashing

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Flash usage

Section	Size
Weather image (.rodata)	~255 KB
Code + HAL	~12 KB
Total	~267 KB / 1024 KB

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License

Code: MIT Map tiles: © OpenStreetMap contributors (ODbL) Weather data: Open-Meteo (CC BY 4.0)