# External buildroot tree for stm32f769 discovery board # This repository provides an external buildroot tree to be used with at least buildroot 2021.02 for the stm32f769 discovery board from STMicroelectronics. It builds a minimal operating system for the target: * Das U-Boot bootloader. * Minimal Linux kernel. * Very small userspace (minimal busybox). The current configuration is built using a prebuilt toolchain from [Bootlin](https://bootlin.com/) to accelerate the build. ## How to build ## First install Buildroot's required dependencies. See: [The buildroot user manual, chapter 2: System requirements](https://buildroot.org/downloads/manual/manual.html#requirement). Also install openocd, it is required for the flashing script (see below). Then set up the required source code: ``` mkdir STM32F769DISCO && cd STM32F769DISCO wget 'https://buildroot.org/downloads/buildroot-2021.02.7.tar.gz' tar -xf buildroot-2021.02.7.tar.gz mv buildroot-2021.02.7 buildroot git clone 'https://git.lumina-sensum.com/git/LuminaSensum/buildroot-stm32f769-disco.git' export BR2_EXTERNAL="$PWD/buildroot-stm32f769-disco" ``` Build the image: ``` cd buildroot make O=output_build stm32f769-disco_defconfig cd output_build make cd ../.. ``` ## Flashing ## To flash the bootloader, run the provided flash.sh script which is located in the external tree: ``` buildroot-stm32f769-disco/board/stm32f769-disco/flash.sh buildroot/output_build ``` ## Installing the operating system ## During build, buildroot creates the sdcard.img file inside the images directory, which you can then simply burn onto a micro sd card using dd: ``` sudo dd if=buildroot-stm32f769-disco/output_build/images/sdcard.img of=/dev/sdX ``` * Notes: * This will destroy any data stored on the micro sd card! * Replace sdX with the correct device node name for your micro sd card!