Flight Core Functional Description

Table of contents

  1. Flight Core Functional Description
    1. Overview
    2. Dimensions
    3. Features
    4. Block Diagram
    5. Orientation
    6. Power Supply
      1. Recommended
      2. Power Usage


ModalAI Flight Core is a PX4 flight controller that uses a very similar architecture to FMUv5x. It’s design goal is to be software compatible with the FMUv5x architecture in a smaller Pixracer-style form factor.


flight-core-dims.png flight_core_v1_imu_locations.png


Feature Details
Weight 6 g
MCU 216MHz, 32-bit ARM M7 STM32F765II
Memory 256Kb FRAM
  2Mbit Flash
  512Kbit SRAM
Firmware PX4
IMUs ICM-20602 (SPI1)
  ICM-42688-P (SPI2)
  BMI088 (SPI6)
Barometer BMP388 (I2C4)
Secure Element A71CH (I2C4)
microSD Card Information on supported cards
Inputs GPS/Mag
  CAN bus
Outputs 6 LEDs (2xRGB)
  8 PWM Channels
Extra Interfaces 3 serial ports


Block Diagram

fc-dk-preliminary-datasheet.png Figure 1



The following is a ‘top down’ view of the Flight Core depicting the orientation. Starting in PX4 v1.11, the orientation is updated to better align with the usage of the VOXL-Flight. The following is a ‘top down’ view of the Flight Core depicting a ROTATION_NONE setup.

PX4 Version Orientation to Achieve Forward Branch Notes
1.10 ROTATION_YAW_180 relesase/1.10 Not Recommended
modalai_1.10 ROTATION_NONE modalai_1.10 Recommended
master ROTATION_NONE master In Development

Flight Core Orientation

Power Supply

A 5VDC supply is required to power the Flight Core. The FC-PM Power Module board is recommended, which provides battery voltage and amperage monitoring through an I2C interface when connected to J6 using the MCBL-00003 cable.

Other connectors also allow a 5VDC supply to be connected (see connectors page )

  • J6 - recommended, provides I2C interace for monitoring
  • J1/J4/J5

Power Usage

NOTE: The following is preliminary data.

Test configuration:

  • Using a 5VDC supply
  • Using PX4 this commit
Use Case Typical Usage (Peak)
Idle 180 mA
Idle, with GPS (HolyBro Pixhawk 4, Second GPS) 260 mA
Idle, with Spektrum DSMX 200 mA
Idle, with Holybro Telemetry 230 mA
Idle, with GPS/Spektrum/Telemetry 330 mA


Pixhawk is a registered trademark of Lorenz Meier.