PX4 Reference Flight Controller Design

The PX4 reference design is the Pixhawk series of flight controllers. First released in 2011, this design is now in its 5th generation (with the 6th generation board design in progress).

Binary Compatibility

All boards manufactured to a particular design are expected to be binary compatible (i.e. can run the same firmware). From 2018 we will offer a binary compatibility test suite that will allow us to verify and certify this compatibility.

FMU generations 1-3 were designed as open hardware, while FMU generations 4 and 5 provided only pinout and power supply specifications (schematics were created by individual manufacturers). In order to better ensure compatibility, FMUv6 and onward will return to a complete reference design model.

Reference Design Generations

• FMUv1: Development board (STM32F407, 128 KB RAM, 1MB flash, schematics) (no longer supported by PX4)
• FMUv2: Pixhawk (STM32F427, 168 MHz, 192 KB RAM, 1MB flash, schematics)
• FMUv3: Pixhawk variants with 2MB flash (3DR Pixhawk 2 (Solo), Hex Pixhawk 2.1, Holybro Pixfalcon, 3DR Pixhawk Mini, STM32F427, 168 MHz, 256 KB RAM, 2 MB flash, schematics)
• FMUv4: Pixracer (STM32F427, 168 MHz, 256 KB RAM, 2 MB flash, pinout)
• FMUv4 PRO: Drotek Pixhawk 3 PRO (STM32F469, 180 MHz, 384 KB RAM, 2 MB flash, pinout)
• FMUv5: Holybro Pixhawk 4 (STM32F765, 216 MHz, 512 KB RAM, 2 MB flash, pinout)
• FMUv6: work in progress, final name TBD, variant 6s (STM32H7, 400 MHz, 2 MB RAM, 2 MB flash) and variant 6i (i.MX RT1050, 600 MHz, 512 KB RAM, external flash)