CBUnmanned H753-SOM

PX4 v1.18

WARNING

PX4 does not manufacture this (or any) autopilot. Contact the manufacturer for hardware support or compliance issues.

The CBUnmanned H753-SOM is a System-on-Module (SoM) flight controller built around the STM32H753 microcontroller. It is intended to be mounted on a carrier board that breaks out the I/O and provides power, peripherals, and connectors for a specific vehicle integration.

INFO

This flight controller is manufacturer supported.

Key Features

• MCU: STM32H753 (32-bit Arm® Cortex®-M7, 480 MHz, 2 MB Flash, 1 MB RAM)
• IMU: Dual InvenSense ICM-42670-P (on SPI4)
• Barometer: ST LPS22HB (on I2C1)
• Storage: microSD card (SDMMC2)
• Interfaces:
  • 6x user UARTs (TEL1, TEL2, TEL3, GPS1, GPS2, RC) plus a debug console — flow control on TEL1/TEL2/TEL3
  • 2x CAN (UAVCAN)
  • 2x external I2C (one per GPS port for compass) and 1x internal I2C (barometer)
  • 1x external SPI (the dual IMUs are on a separate internal SPI bus)
  • 9x PWM outputs (DShot / Bi-Directional DShot supported)
  • USB
  • Ethernet optional
• Power: Powered from an external regulated 5 V supply (e.g. a BEC on the carrier board). Battery voltage (up to 65 V) and current are monitored via ADC; the voltage sense input is a separate pin behind a voltage divider and does not power the board.

INFO

CAN transceivers require a 5 V supply. USB-only power (≈4.5 V after the input diode) is not sufficient to operate the CAN bus.

Where to Buy

Check CBUnmanned for availability.

Building Firmware

TIP

Most users will not need to build this firmware. It is pre-built and automatically installed by QGroundControl when appropriate hardware is connected.

To build PX4 for this target from source:

make cbunmanned_h753-som_default

Serial Port Mapping

UART	Device	PX4 Default	Pins (TX / RX)	Flow Control (CTS / RTS)
USART2	/dev/ttyS0	TEL1	PD5 / PA3	PA0 / PD4
USART3	/dev/ttyS1	GPS1	PD8 / PD9	—
UART4	/dev/ttyS2	GPS2	PC10 / PC11	—
UART5	/dev/ttyS3	Console	PC12 / PD2	—
USART6	/dev/ttyS4	RC	PC6 / PC7	—
UART7	/dev/ttyS5	TEL2	PE8 / PE7	PE10 / PE9
UART8	/dev/ttyS6	TEL3	PE1 / PE0	PD14 / PD15

PWM Outputs

The board provides 9 PWM outputs, all of which support DShot and Bidirectional DShot.

The outputs are split across 4 timer groups:

Outputs	Timer
1, 2, 3	Timer1
4, 5	Timer2
6, 7, 8	Timer3
9	Timer4

All outputs within the same group must use the same protocol and update rate.

Debug Port

The system console runs on UART5 (PC12 / PD2). USB CDC ACM is auto-started and provides MAVLink access.

PX4 Bootloader Update

Boards that ship without the PX4 bootloader must have it flashed before PX4 firmware can be installed. Download the cbunmanned_h753-som_bootloader.bin bootloader binary and follow the DFU Bootloader Update instructions.

Once the PX4 bootloader is flashed, firmware can be installed normally via QGroundControl.