PX4 User Guide

# Pixhawk 4 Mini

The Pixhawk® 4 Mini autopilot is designed for engineers and hobbyists who are looking to tap into the power of Pixhawk 4 but are working with smaller drones. Pixhawk 4 Mini takes the FMU processor and memory resources from the Pixhawk 4 while eliminating interfaces that are normally unused. This allows the Pixhawk 4 Mini to be small enough to fit in a 250mm racer drone.

Pixhawk 4 Mini was designed and developed in collaboration with Holybro® and Auterion®. It is based on the Pixhawk FMUv5 design standard and is optimized to run PX4 flight control software.

Pixhawk4 mini

Tip This autopilot is supported by the PX4 maintenance and test teams.

# Quick Summary

  • Main FMU Processor: STM32F765
    • 32 Bit Arm® Cortex®-M7, 216MHz, 2MB memory, 512KB RAM
  • On-board sensors:
    • Accel/Gyro: ICM-20689
    • Accel/Gyro: BMI055
    • Magnetometer: IST8310
    • Barometer: MS5611
  • GPS: ublox Neo-M8N GPS/GLONASS receiver; integrated magnetometer IST8310
  • Interfaces:
    • 8 PWM outputs
    • 4 dedicated PWM/Capture inputs on FMU
    • Dedicated R/C input for CPPM
    • Dedicated R/C input for Spektrum / DSM and S.Bus with analog / PWM RSSI input
    • 3 general purpose serial ports
    • 2 I2C ports
    • 3 SPI buses
    • 1 CANBuses for CAN ESC
    • Analog inputs for voltage / current of battery
    • 2 additional analog input
  • Power System:
    • Power Brick Input: 4.75~5.5V
    • USB Power Input: 4.75~5.25V
    • Servo Rail Input: 0~24V
    • Max current sensing: 120A
  • Weight and Dimensions:
    • Weight: 37.2g
    • Dimensions: 38x55x15.5mm
  • Other Characteristics:
    • Operating temperature: -40 ~ 85°c

Additional information can be found in the Pixhawk 4 Mini Technical Data Sheet.

# Purchase

Order from Holybro.

# Interfaces

Pixhawk 4 Mini interfaces

Warning The RC IN and PPM ports are for RC receivers only. These are powered! NEVER connect any servos, power supplies or batteries (or to any connected receiver).

# Pinouts

Download Pixhawk 4 Mini pinouts from here.

# Dimensions

Pixhawk 4 Mini Dimensions

# Voltage Ratings

Pixhawk 4 Mini can have power supply redundancy — if two power sources are supplied. The power rails are: POWER and USB.

Note The output power rail of MAIN OUT does not power the flight controller board (and is not powered by it). You must supply power to one of POWER or USB or the board will be unpowered.

Normal Operation Maximum Ratings

Under these conditions all power sources will be used in this order to power the system:

  1. POWER (4.75V to 5.5V)
  2. USB input (4.75V to 5.25V)

Absolute Maximum Ratings

Under these conditions the system will remain intact.

  1. POWER input (0V to 6V undamaged)
  2. USB input (0V to 6V undamaged)
  3. Servo input: VDD_SERVO pin of MAIN OUT (0V to 24V undamaged)

# Assembly/Setup

The Pixhawk 4 Mini Wiring Quick Start provides instructions on how to assemble required/important peripherals including GPS, Power Management Board, etc.

# 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:

make px4_fmu-v5_default

# Debug Port

The PX4 System Console and SWD interface run on the FMU Debug port. In order to access these ports, the user must remove the Pixhawk 4 Mini casing.

Pixhawk 4 Mini FMU Debug

The port has a standard serial pinout and can be connected to a standard FTDI cable (3.3V, but it's 5V tolerant) or a Dronecode probe. The pinout uses the standard Pixhawk debug connector pinout. Please refer to the wiring page for details of how to wire up this port.

# Serial Port Mapping

UART Device Port
UART1 /dev/ttyS0 GPS
USART2 /dev/ttyS1 TELEM1 (flow control)
USART3 /dev/ttyS2 TELEM2 (flow control)
UART4 /dev/ttyS3 TELEM4
USART6 /dev/ttyS4 TX is RC input from SBUS_RC connector
UART7 /dev/ttyS5 Debug Console
UART8 /dev/ttyS6 Not connected (no PX4IO)

# Peripherals

# Supported Platforms

Motors and servos are connected to the MAIN OUT ports in the order specified for your vehicle in the Airframe Reference. This reference lists the output port to motor/servo mapping for all supported air and ground frames (if your frame is not listed in the reference then use a "generic" airframe of the correct type).

Warning Pixhawk 4 Mini does not have AUX ports. The board cannot be used with frames that require more than 8 ports or which use AUX ports for motors or control surfaces. It can be used for airframes that use AUX for non-essential peripherals (e.g. "feed-through of RC AUX1 channel").

# Further info