SprinterOS

A lightweight Real-Time OS and Bootloader for Cortex-M7, completely bare-metal

The goal is to bring up a CORTEX-M7 based STM32F767ZI chip, with no help from HAL or any external libraries, purely by reading reference manuals & datasheets. At the end:

• bootloader
• true real-time kernel
• user facing CLI that resembles linux

With all the features, we're stuck with only 2MB of FLASH, around half we need for user. Also, we only have 512KB of memory. As a result, the OS is written with extreme care for the size and resource constraints

1. Connect a SPI based SD card reader onto a SPI. make sure to edit the main bootloader to reflect this if you do!

// change SPIx to the right SPI you are using
if (init_spi(&spi_master, SPI1)) {

2. Build and load the bootloader. For STM platforms, the recommended approach is via the st-flash utility

cd boot

make clean
make boot

// ensure that your device is connected
st-flash write build/boot.bin 0x08000000

3. Build and load the kernel

cd kernel

make clean
make sprinter

// ensure that the SD card is connected your computer, and use the sprinterloader utility
cd ..
cd tools
./sprinterloader.sh <kernel_img_location> <disk>

4. Connect to UART (UART_1 is currently supported), you should see UART logs from boot and kernel upon boot!

• ARM CORTEX-M7 Based Hardware (STM32F767ZI used as dev chip)

• For any inquiries, please reach out to xsmu0922@gmail.com