PX4 User Guide (v1.14)

# 3DR Pixhawk 1 Flight Controller (Discontinued)

WARNING

This flight controller has been discontinued and is no longer commercially available. You can use the mRo Pixhawk as a drop-in replacement.

WARNING

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

The 3DR Pixhawk® 1 autopilot is a popular general purpose flight controller based on the Pixhawk-project (opens new window) FMUv2 open hardware design (it combines the functionality of the PX4FMU + PX4IO). It runs PX4 on the NuttX (opens new window) OS.

Pixhawk Image

Assembly/setup instructions for use with PX4 are provided here: Pixhawk Wiring Quickstart

# Key Features

  • Main System-on-Chip: STM32F427 (opens new window)
    • CPU: 180 MHz ARM® Cortex® M4 with single-precision FPU
    • RAM: 256 KB SRAM (L1)
  • Failsafe System-on-Chip: STM32F100
    • CPU: 24 MHz ARM Cortex M3
    • RAM: 8 KB SRAM
  • Wifi: ESP8266 external
  • GPS: u-blox® 7/8 (Hobbyking®) / u-blox 6 (3D Robotics)
  • Optical flow: PX4 Flow unit
  • Redundant power supply inputs and automatic failover
  • External safety switch
  • Multicolor LED main visual indicator
  • High-power, multi-tone piezo audio indicator
  • microSD card for high-rate logging over extended periods of time

Connectivity

  • 1x I2C
  • 1x CAN (2x optional)
  • 1x ADC
  • 4x UART (2x with flow control)
  • 1x Console
  • 8x PWM with manual override
  • 6x PWM / GPIO / PWM input
  • S.BUS / PPM / Spektrum input
  • S.BUS output

# Where to Buy

Originally manufactured by 3DR® this board was the original standard microcontroller platform for PX4®. While the board is no longer manufactured by 3DR, you can use the mRo Pixhawk as a drop-in replacement.

Order mRo Pixhawk from:

# Specifications

# Processor

# Sensors

  • ST Micro L3GD20H 16 bit gyroscope
  • ST Micro LSM303D 14 bit accelerometer / magnetometer
  • Invensense MPU 6000 3-axis accelerometer/gyroscope
  • MEAS MS5611 barometer

# Interfaces

  • 5x UART (serial ports), one high-power capable, 2x with HW flow control
  • 2x CAN (one with internal 3.3V transceiver, one on expansion connector)
  • Spektrum DSM / DSM2 / DSM-X® Satellite compatible input
  • Futaba S.BUS® compatible input and output
  • PPM sum signal input
  • RSSI (PWM or voltage) input
  • I2C
  • SPI
  • 3.3 and 6.6V ADC inputs
  • Internal microUSB port and external microUSB port extension

# Power System and Protection

  • Ideal diode controller with automatic failover
  • Servo rail high-power (max. 10V) and high-current (10A+) ready
  • All peripheral outputs over-current protected, all inputs ESD protected

# Voltage Ratings

Pixhawk can be triple-redundant on the power supply if three power sources are supplied. The three rails are: Power module input, servo rail input, USB input.

# Normal Operation Maximum Ratings

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

  • Power module input (4.8V to 5.4V)
  • Servo rail input (4.8V to 5.4V) UP TO 10V FOR MANUAL OVERRIDE, BUT AUTOPILOT PART WILL BE UNPOWERED ABOVE 5.7V IF POWER MODULE INPUT IS NOT PRESENT
  • USB power input (4.8V to 5.4V)

# Absolute Maximum Ratings

Under these conditions the system will not draw any power (will not be operational), but will remain intact.

  • Power module input (4.1V to 5.7V, 0V to 20V undamaged)
  • Servo rail input (4.1V to 5.7V, 0V to 20V)
  • USB power input (4.1V to 5.7V, 0V to 6V)

# Schematics

FMUv2 + IOv2 schematic (opens new window) -- Schematic and layout

Note

As a CC-BY-SA 3.0 licensed Open Hardware design, all schematics and design files are available (opens new window).

# Connections

Pixhawk ports are shown below. These use Hirose DF13 connectors (predating the JST-GH connectors defined in the Pixhawk connector standard).

WARNING

Many 3DR Pixhawk clones use Molex picoblade connectors instead of DF13 connectors. They have rectangular instead of square pins, and cannot be assumed to be compatible.

Pixhawk Connectors

TIP

The RC IN port is for RC receivers only and provides sufficient power for that purpose. NEVER connect any servos, power supplies or batteries to it or to the receiver connected to it.

# Pinouts

# TELEM1, TELEM2 ports

Pin Signal Volt
1 (red) VCC +5V
2 (blk) TX (OUT) +3.3V
3 (blk) RX (IN) +3.3V
4 (blk) CTS (IN) +3.3V
5 (blk) RTS (OUT) +3.3V
6 (blk) GND GND

# GPS port

Pin Signal Volt
1 (red) VCC +5V
2 (blk) TX (OUT) +3.3V
3 (blk) RX (IN) +3.3V
4 (blk) CAN2 TX +3.3V
5 (blk) CAN2 RX +3.3V
6 (blk) GND GND

# SERIAL 4/5 port

Due to space constraints two ports are on one connector.

Pin Signal Volt
1 (red) VCC +5V
2 (blk) TX (#4) +3.3V
3 (blk) RX (#4) +3.3V
4 (blk) TX (#5) +3.3V
5 (blk) RX (#5) +3.3V
6 (blk) GND GND

# ADC 6.6V

Pin Signal Volt
1 (red) VCC +5V
2 (blk) ADC IN up to +6.6V
3 (blk) GND GND

# ADC 3.3V

Pin Signal Volt
1 (red) VCC +5V
2 (blk) ADC IN up to +3.3V
3 (blk) GND GND
4 (blk) ADC IN up to +3.3V
5 (blk) GND GND

# I2C

Pin Signal Volt
1 (red) VCC +5V
2 (blk) SCL +3.3 (pullups)
3 (blk) SDA +3.3 (pullups)
4 (blk) GND GND

# CAN

Pin Signal Volt
1 (red) VCC +5V
2 (blk) CAN_H +12V
3 (blk) CAN_L +12V
4 (blk) GND GND

# SPI

Pin Signal Volt
1 (red) VCC +5V
2 (blk) SPI_EXT_SCK +3.3
3 (blk) SPI_EXT_MISO +3.3
4 (blk) SPI_EXT_MOSI +3.3
5 (blk) !SPI_EXT_NSS +3.3
6 (blk) !GPIO_EXT +3.3
7 (blk) GND GND

# POWER

Pin Signal Volt
1 (red) VCC +5V
2 (blk) VCC +5V
3 (blk) CURRENT +3.3V
4 (blk) VOLTAGE +3.3V
5 (blk) GND GND
6 (blk) GND GND

# SWITCH

Pin Signal Volt
1 (red) VCC +3.3V
2 (blk) !IO_LED_SAFETY GND
3 (blk) SAFETY GND

# Serial Port Mapping

UART Device Port
UART1 /dev/ttyS0 IO debug
USART2 /dev/ttyS1 TELEM1 (flow control)
USART3 /dev/ttyS2 TELEM2 (flow control)
UART4
UART7 CONSOLE
UART8 SERIAL4

# Debug Ports

# Console Port

The PX4 System Console runs on the port labeled SERIAL4/5.

TIP

A convenient way to connect to the console is to use a Dronecode probe (opens new window), as it comes with connectors that can be used with several different Pixhawk devices. Simply connect the 6-pos DF13 1:1 cable on the Dronecode probe (opens new window) to the Pixhawk SERIAL4/5 port.

Dronecode probe

The pinout is standard serial pinout, designed to connect to a 3.3V FTDI (opens new window) cable (5V tolerant).

3DR Pixhawk 1 FTDI
1 +5V (red)
2 S4 Tx
3 S4 Rx
4 S5 Tx 5
5 S5 Rx 4
6 GND 1

The wiring for an FTDI cable to a 6-pos DF13 1:1 connector is shown in the figure below.

Console Connector

The complete wiring is shown below.

Console Debug

Note

For information on how to use the console see: System Console.

# SWD Port

The SWD (JTAG) ports are hidden under the cover (which must be removed for hardware debugging). There are separate ports for FMU and IO, as highlighted below.

Pixhawk SWD

The ports are ARM 10-pin JTAG connectors, which you will probably have to solder. The pinout for the ports is shown below (the square markers in the corners above indicates pin 1).

ARM 10-Pin connector pinout

Note

All Pixhawk FMUv2 boards have a similar SWD port.

# 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-v2_default

# Parts / Housings

# Supported Platforms / Airframes

Any multicopter / airplane / rover or boat that can be controlled with normal RC servos or Futaba S-Bus servos.

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