Build configurations

Preset	Configuration	Clock setup	Use
`stm32vldiscovery`	`configs/stm32vldiscovery_defconfig`	PLL to 24 MHz	Physical board
`stm32vldiscovery-qemu`	same defconfig + overlay `src/board/stm32vldiscovery/qemu.yaml`	Skipped	QEMU only

cmake --preset stm32vldiscovery-qemu -DPython3_EXECUTABLE="$PWD/.venv/bin/python"
cmake --build --preset stm32vldiscovery-qemu
bash scripts/run-qemu-stm32vldiscovery.sh
python3 tests/qemu_files_test.py --board stm32vldiscovery

QEMU maps its first serial port to USART1. Exit the interactive session with Ctrl-A, then X.

Warning: Do not flash the QEMU build to a physical board. It skips clock setup, so the board would run at the 8 MHz reset clock while assuming 24 MHz.

Clock

With clock_setup true (the default in board.yaml), board_init() runs the PLL from HSI/2 × 6 = 24 MHz, the STM32F100 maximum, with undivided AHB, APB1, and APB2 clocks. Each step waits with a bounded iteration budget; a failure halts before the console starts, so diagnose it with a debugger.

QEMU does not model the clock controller or GPIO: reads return 0 and writes are ignored. Its CPU and SysTick clock is fixed at 24 MHz, so the QEMU overlay (qemu.yaml, clock_setup: false) skips clock setup and the board reports 24 MHz in both configurations.

Memory budget

Both defconfigs change four defaults to fit 8 KB of RAM:

Setting	Default	This board
`CONFIG_HOMECORE_KERNEL_MAIN_STACK_SIZE`	3072	2048
`CONFIG_HOMECORE_SHELL_BASIC_MAX_NESTING`	8	4
`CONFIG_HOMECORE_VFS_MAX_FILE_SIZE`	4096	1024
`CONFIG_HOMECORE_KERNEL_STDIO_BUFFERED`	y	n (saves about 2 KB of heap)

VFS entries and descriptors use heap only while they exist, so the default caps of 16 files, 16 directories, and 16 open files are kept. In QEMU, about 450 bytes of heap are used after boot, and 16 directories plus 16 empty files add about 2 KB. File contents, BASIC programs, and variables share the remaining heap. When it runs out, creating an entry fails with "Not enough space" (ENOMEM), which differs from "No space left on device" at a cap.

BASIC lines may nest parentheses, unary signs, function calls, and IF ... THEN up to 4 levels. Measured stack peaks in QEMU are about 0.9 KB for file commands and 1.7 KB for BASIC at the nesting limit, leaving about 380 bytes of margin. mem reports heap use and the stack high-water mark.

Console wiring (physical board)

Board pin	Adapter pin
PA9 (USART1 TX)	RX
PA10 (USART1 RX)	TX
GND	GND

Use a 3.3 V USB-to-UART adapter at 115200 baud, 8N1, no flow control. The on-board ST-LINK/V1 has no virtual COM port. OpenOCD provides board/stm32vldiscovery.cfg for it; on Linux the ST-LINK/V1 needs the usb-storage quirk 483:3744:i. These flashing steps have not been checked with this port:

openocd -f board/stm32vldiscovery.cfg \

-c "program build/stm32vldiscovery/homecore verify reset exit"

LEDs

File	LED	Pin
`/dev/led0`	LD3 green	PC9
`/dev/led1`	LD4 blue	PC8

Both are GPIO LEDs on port C, lit when the pin is high. QEMU models no GPIO, so the stm32vldiscovery-qemu build's overlay disables them and enables console LEDs with the same files, which print [led0] on and similar lines. See LEDs.

Hardware validation checklist

Confirm the banner, uptime against elapsed time (which checks the 24 MHz PLL), mem, the file commands, basic, the LEDs (write /dev/led0 on lights LD3), and reboot, as described in the porting guide.

The full board guide is docs/boards/stm32vldiscovery.md.

SoC	ST STM32F100RB (`st/stm32f100`)
Core	Cortex-M3
Flash	128 KB at `0x08000000`
RAM	8 KB at `0x20000000`
Clock	24 MHz, PLL from HSI/2 × 6
Console	USART1, PA9 TX / PA10 RX, 115200 8N1
Presets	`stm32vldiscovery`, `stm32vldiscovery-qemu`

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