sensor-fw

Aleph STM32 Firmware

This is the firmware for the STM32H747 MCU on the Aleph FC. It reads sensor data from the IMU, magnetometer, and barometer at a high rate, and stores it on the SD card. It also streams the data over the board-to-board UART to the Orin NX carrier board.

Pre-requisites

• rust + cargo
• probe-rs or openocd
• flip-link
• defmt-print for RTT logging: cargo binstall defmt-print

Flashing instructions

1. Connect Aleph FC to your computer using a USB-C cable.
2. Verify that Aleph FC is detected:

probe-rs info --protocol swd

# expected output:
ARM Chip with debug port Default:
Debug Port: DPv2, Designer: STMicroelectronics, Part: 0x4500, Revision: 0x0, Instance: 0x00
├── 0 MemoryAP
│   └── ROM Table (Class 1), Designer: STMicroelectronics
│       ├── ROM Table (Class 1), Designer: ARM Ltd
│       │   ├── Cortex-M4 SCS   (Generic IP component)
│       │   │   └── CPUID
│       │   │       ├── IMPLEMENTER: ARM Ltd
│       │   │       ├── VARIANT: 1
│       │   │       ├── PARTNO: Cortex-M7
│       │   │       └── REVISION: 1
│       │   ├── Cortex-M3 DWT   (Generic IP component)
│       │   ├── Cortex-M7 FBP   (Generic IP component)
│       │   └── Cortex-M3 ITM   (Generic IP component)
│       ├── Cortex-M7 ETM   (Coresight Component)
│       └── Coresight Component, Part: 0x0906, Devtype: 0x14, Archid: 0x0000, Designer: ARM Ltd

3. Build and flash the firmware from the fsw/sensor-fw directory:

# Option 1: Using probe-rs (quick)
cargo rrb fw

# Option 2: Using OpenOCD with RTT logging (includes live logs)
cargo build --release --bin fw
../openocd/flash.sh target/thumbv7em-none-eabihf/release/fw --defmt

Convert binary telemetry data to CSV

1. Connect SD card to your computer.
2. Find the path to the binary file on the SD card (should be something like /Volumes/<sd_card>/DATA.BIN).
3. Run the blackbox CLI from the fsw/blackbox directory:

cargo run --release -- <path_to_binary_file>

4. The CSV output will printed to stdout. You can redirect it to a file by running:

cargo run --release -- <path_to_binary_file> > <output_file>.csv

Appendix

Debugging and recovery

Flash manually using probe-rs

# build the firmware:
cargo build --release --bin fw
# flash the firmware:
probe-rs run --chip STM32H747IITx target/thumbv7em-none-eabihf/release/fw

Flash + RTT using openocd

# build the firmware:
cargo build --release --bin fw
# flash the firmware + attach to RTT with defmt logging
../openocd/flash.sh target/thumbv7em-none-eabihf/release/fw --defmt 

Erase all internal flash memory

probe-rs erase --chip STM32H747IITx

This is useful if portions of the internal flash are being used by the firmware to store data, and it needs to be cleared. E.g. Betaflight uses the internal flash to store configuration data.

Soft reset the MCU over SWD

probe-rs reset --chip STM32H747IITx

Hard reset the MCU (using the nRST pin)

probe-rs reset --chip STM32H747IITx --connect-under-reset