# Holybro Pixhawk 4
:::warning
PX4 does not manufacture this (or any) autopilot.
Contact the [manufacturer](https://holybro.com/) for hardware support or compliance issues.
:::
_Pixhawk 4_® is an advanced autopilot designed and made in collaboration with Holybro® and the PX4 team.
It is optimized to run PX4 v1.7 and later, and is suitable for academic and commercial developers.
It is based on the [Pixhawk-project](https://pixhawk.org/) **FMUv5** open hardware design and runs PX4 on the [NuttX](https://nuttx.apache.org/) OS.
:::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
- IO Processor: STM32F100
- 32 Bit Arm® Cortex®-M3, 24MHz, 8KB SRAM
- 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:
- 8-16 PWM outputs (8 from IO, 8 from FMU)
- 3 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
- Dedicated S.Bus servo output
- 5 general purpose serial ports
- 3 I2C ports
- 4 SPI buses
- Up to 2 CANBuses for dual CAN with serial ESC
- Analog inputs for voltage / current of 2 batteries
- Power System:
- Power module output: 4.9~5.5V
- USB Power Input: 4.75~5.25V
- Servo Rail Input: 0~36V
- Weight and Dimensions:
- Weight: 15.8g
- Dimensions: 44x84x12mm
- Other Characteristics:
- Operating temperature: -40 ~ 85°c
Additional information can be found in the [Pixhawk 4 Technical Data Sheet](https://github.com/PX4/PX4-user_guide/raw/main/assets/flight_controller/pixhawk4/pixhawk4_technical_data_sheet.pdf).
## Where to Buy
Order from [Holybro](https://holybro.com/products/pixhawk-4).
## Connectors
:::warning
The **DSM/SBUS RC** and **PPM RC** 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_ pinouts from [here](https://cdn.shopify.com/s/files/1/0604/5905/7341/files/Pixhawk4-Pinouts.pdf).
::: info
Connector pin assignments are left to right (i.e. Pin 1 is the left-most pin).
The exception is the [debug port(s)](#debug_port) (pin 1 is the right-most, as shown below).
:::
## 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 | RC SBUS |
| UART7 | /dev/ttyS5 | Debug Console |
| UART8 | /dev/ttyS6 | PX4IO |
## Dimensions
## Voltage Ratings
_Pixhawk 4_ can be triple-redundant on the power supply if three power sources are supplied. The three power rails are: **POWER1**, **POWER2** and **USB**.
::: info
The output power rails **FMU PWM OUT** and **I/O PWM OUT** (0V to 36V) do not power the flight controller board (and are not powered by it).
You must supply power to one of **POWER1**, **POWER2** 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. **POWER1** and **POWER2** inputs (4.9V to 5.5V)
1. **USB** input (4.75V to 5.25V)
**Absolute Maximum Ratings**
Under these conditions the system will not draw any power (will not be operational), but will remain intact.
1. **POWER1** and **POWER2** inputs (operational range 4.1V to 5.7V, 0V to 10V undamaged)
1. **USB** input (operational range 4.1V to 5.7V, 0V to 6V undamaged)
1. Servo input: VDD_SERVO pin of **FMU PWM OUT** and **I/O PWM OUT** (0V to 42V undamaged)
## Assembly/Setup
The [Pixhawk 4 Wiring Quick Start](../assembly/quick_start_pixhawk4.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, while the I/O console and SWD interface can be accessed via **I/O Debug** port.
In order to access these ports, the user must remove the _Pixhawk 4_ casing.
The pinout uses the standard [Pixhawk debug connector pinout](https://github.com/pixhawk/Pixhawk-Standards/blob/master/DS-009%20Pixhawk%20Connector%20Standard.pdf).
For wiring information see:
- [System Console > Pixhawk Debug Port](../debug/system_console.md#pixhawk_debug_port)
## Peripherals
- [Digital Airspeed Sensor](https://store-drotek.com/793-digital-differential-airspeed-sensor-kit-.html)
- [Telemetry Radio Modules](../telemetry/index.md)
- [Rangefinders/Distance sensors](../sensor/rangefinders.md)
## Supported Platforms / Airframes
Any multicopter / airplane / rover or boat that can be controlled with normal RC servos or Futaba S-Bus servos.
The complete set of supported configurations can be seen in the [Airframes Reference](../airframes/airframe_reference.md).
## Further info
- [Pixhawk 4 Technical Data Sheet](https://github.com/PX4/PX4-user_guide/raw/main/assets/flight_controller/pixhawk4/pixhawk4_technical_data_sheet.pdf)
- [FMUv5 reference design pinout](https://docs.google.com/spreadsheets/d/1-n0__BYDedQrc_2NHqBenG1DNepAgnHpSGglke-QQwY/edit#gid=912976165).
- [Pixhawk 4 Wiring QuickStart](../assembly/quick_start_pixhawk4.md)
- [Pixhawk 4 Pinouts](https://cdn.shopify.com/s/files/1/0604/5905/7341/files/Pixhawk4-Pinouts.pdf) (Holybro)
- [Pixhawk 4 Quick Start Guide](https://cdn.shopify.com/s/files/1/0604/5905/7341/files/Pixhawk4-quickstartguide.pdf) (Holybro)