# Holybro Pixhawk 4 Mini (Discontinued)
:::warning
PX4 does not manufacture this (or any) autopilot.
Contact the [manufacturer](https://holybro.com/) for hardware support or compliance issues.
:::
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](https://pixhawk.org/) **FMUv5** design standard and is optimized to run PX4 flight control software.
:::tip
This autopilot is [supported](../flight_controller/autopilot_pixhawk_standard.md) 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 or ICM20602
- Magnetometer: IST8310
- Barometer: MS5611
- GPS: u-blox 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](https://github.com/PX4/PX4-user_guide/raw/main/assets/flight_controller/pixhawk4mini/pixhawk4mini_technical_data_sheet.pdf).
## Where to Buy
Order from [Holybro](https://holybro.com/collections/autopilot-flight-controllers/products/pixhawk4-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](https://github.com/PX4/PX4-user_guide/raw/main/assets/flight_controller/pixhawk4mini/pixhawk4mini_pinouts.pdf).
## Dimensions
## Voltage Ratings
_Pixhawk 4 Mini_ can have power supply redundancy — if two power sources are supplied. The power rails are: **POWER** and **USB**.
::: info
The output power rail of **MAIN OUT** does not power the flight controller board (and is not powered by it).
You must [supply power](../assembly/quick_start_pixhawk4_mini.md#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)
1. **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)
1. **USB** input (0V to 6V undamaged)
1. Servo input: VDD_SERVO pin of **MAIN OUT** (0V to 24V undamaged)
## Assembly/Setup
The [_Pixhawk 4 Mini_ Wiring Quick Start](../assembly/quick_start_pixhawk4_mini.md) 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](../dev_setup/building_px4.md) for this target:
```
make px4_fmu-v5_default
```
## Debug Port
The [PX4 System Console](../debug/system_console.md) and [SWD interface](../debug/swd_debug.md) run on the **FMU Debug** port.
In order to access these ports, the user must remove the _Pixhawk 4 Mini_ casing.
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](https://kb.zubax.com/display/MAINKB/Dronecode+Probe+documentation). The pinout uses the standard [Pixhawk debug connector](https://github.com/pixhawk/Pixhawk-Standards/blob/master/DS-009%20Pixhawk%20Connector%20Standard.pdf) pinout. Please refer to the [wiring](../debug/system_console.md) page for details of how to wire up this port.
## Serial Port Mapping
| UART | Device | QGC Parameter Description | Port Label on FC |
| :----: | :--------: | :-----------------------: | :----------------------: |
| UART1 | /dev/ttyS0 | GPS1 | GPS Module |
| USART2 | /dev/ttyS1 | TELEM1 | TELEM1 |
| USART3 | /dev/ttyS2 | TELEM2 | N/A |
| UART4 | /dev/ttyS3 | TELEM/SERIAL4 | UART/l2C B |
| USART6 | /dev/ttyS4 | N/A | RC IN |
| UART7 | /dev/ttyS5 | N/A | Debug |
| UART8 | /dev/ttyS6 | N/A | Not connected (no PX4IO) |
## Peripherals
- [Digital Airspeed Sensor](https://holybro.com/products/digital-air-speed-sensor)
- [Telemetry Radio Modules](../telemetry/index.md)
- [Rangefinders/Distance sensors](../sensor/rangefinders.md)
## Supported Platforms
Motors and servos are connected to the **MAIN OUT** ports in the order specified for your vehicle in the [Airframe Reference](../airframes/airframe_reference.md).
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
- [_Pixhawk 4 Mini_ Technical Data Sheet](https://github.com/PX4/PX4-user_guide/raw/main/assets/flight_controller/pixhawk4mini/pixhawk4mini_technical_data_sheet.pdf)
- [FMUv5 reference design pinout](https://docs.google.com/spreadsheets/d/1-n0__BYDedQrc_2NHqBenG1DNepAgnHpSGglke-QQwY/edit#gid=912976165).