Quick Start Guide

Supported Boards

F9 Microkernel supports the following boards:

• STM32F4DISCOVERY
• STM32F429I-DISC1
• NUCLEO-F429ZI
  • All supported boards are based on the ARM Cortex-M4F core. F9 should work on any STM32F40x/STM32F429/STM32F439 microcontroller.
• B-L475E-IOT01A
  • Supported by upstream QEMU and used as the default emulation target.

Toolchain Requirements

Building F9 Microkernel requires an arm-none-eabi toolchain with Cortex-M4F support:

• Arm GNU Toolchain
  • Download the AArch32 bare-metal target (arm-none-eabi) package.

Building F9

Configuration

Configuration is the first build step. Run make config to select options. The build system generates a .config file and a configuration header include/autoconf.h for C programs.

Compilation

Run make to build. Output files are placed in the build directory.

Flashing and Debugging

STM32F4 Boards

For flashing and debugging on STM32F4 boards, stlink is required. With st-flash in the PATH, make flash programs the STM32F4DISCOVERY board with the built F9 binary image.

Source-level debugging with gdb is possible via OpenOCD or stlink, but may be limited on resource-constrained targets.

In-Kernel Debugger (KDB)

KDB (in-kernel debugger) is enabled by default and provides essential kernel inspection. Press ? to display the menu:

Key	Function
a	Dump address spaces
e	Dump ktimer events
K	Print kernel tables
m	Dump memory pools
M	Dump MPU status
n	Show timer (now)
p	Show sampling (requires SYMMAP)
s	Show softirqs
t	Dump threads
v	Show tickless scheduling status

KDB communicates via USART. The port can be selected during make config.

Serial Port Configuration

STM32F4DISCOVERY

Port	TX Pin	RX Pin
USART4	PA0	PA1
USART2	PA2	PA3
USART1	PA9	PA10

STM32F429I-DISC1

Port	TX Pin	RX Pin
USART4	PC11	PC10
USART2	PD5	PD6
USART1	PA9	PA10

NUCLEO-F429ZI

Port	TX Pin	RX Pin
USART3	PD8	PD9
USART2	PD5	PD6
USART1	PB6	PB7

Note: On the NUCLEO-F429ZI, USART3 is connected to the on-board VCOM (Virtual COM Port) provided by the ST-LINK.

QEMU Emulation

For B-L475E-IOT01A under QEMU, semihosting carries normal console output and USART1 is reserved for KDB input. Run with:

qemu-system-arm -M b-l475e-iot01a -nographic \
    -semihosting -serial mon:stdio \
    -kernel build/b-l475e-iot01a/f9.elf

Note: -serial mon:stdio is still required for interactive KDB shell. The mon: prefix enables QEMU monitor access via Ctrl+A then c. Exit with Ctrl+A then x.

Serial Terminal Setup

For physical boards, connect a USB-to-serial adapter and use a terminal emulator at 115200 baud, 8N1. For example, with screen:

screen /dev/ttyUSB0 115200 8n1

Press Ctrl-a and `k to exit screen.