Hex Cube Black Flight Controller

The Hex Cube Black flight controller (previously known as Pixhawk 2.1) is a flexible autopilot intended primarily for manufacturers of commercial systems. It is based on the Pixhawk-project FMUv3 open hardware design and runs PX4 on the NuttX OS.

The controller is designed to be used with a domain-specific carrier board in order to reduce the wiring, improve reliability, and ease of assembly. For example, a carrier board for a commercial inspection vehicle might include connections for a companion computer, while a carrier board for a racer could includes ESCs form the frame of the vehicle.

Cube includes vibration isolation on two of the IMU's, with a third fixed IMU as a reference / Backup.

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

Key Features

• 32bit STM32F427 Cortex-M4F^® core with FPU
• 168 MHz / 252 MIPS
• 256 KB RAM
• 2 MB Flash (fully accessible)
• 32 bit STM32F103 failsafe co-processor
• 14 PWM / Servo outputs (8 with failsafe and manual override, 6 auxiliary, high-power compatible)
• Abundant connectivity options for additional peripherals (UART, I2C, CAN)
• Integrated backup system for in-flight recovery and manual override with dedicated processor and stand-alone power supply (fixed-wing use)
• Backup system integrates mixing, providing consistent autopilot and manual override mixing modes (fixed wing use)
• 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

Where to Buy

• The Cube (ProfiCNC)

Specifications

Processor

• 32bit STM32F427 Cortex M4 core with FPU
• 168 MHz / 252 MIPS
• 256 KB RAM
• 2 MB Flash (fully accessible)
• 32 bit STM32F103 failsafe co-processor

Sensors

• TBA

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
• 3.3v ADC input
• 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)

Pinouts and Schematics

Board schematics and other documentation can be found here: The Cube Project.

All other Cube documentation, including pinouts can be found at docs.cubepilot.org (e.g. Cube Module Overview, Mini Carrier Board etc.).

Serial Port Mapping

Ports

Top-Side (GPS, TELEM etc)

Serial Ports

The serial port mappings are as below:

• GPS1:/dev/ttyS3
• TEL1: /dev/ttyS1
• TEL2: /dev/ttyS2
• TEL4: /dev/ttyS6 (ttyS4 UART)

  TEL4 is labeled as GPS2 on Cube.

Debug Ports

USB/SDCard Ports

Building Firmware

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-v3_default

Issues

CAN1 and CAN2 silk screen on the Pixhawk 2.1 are flipped (CAN1 is CAN2 and vice versa).