FCH7 - Flight Controller for Drone Quadcopter

Overview

FCH7 is a project aimed at developing a flight controller based on the STM32H743VITx MCU for drones with 4 to 8 motors, designed using KiCad. The flight controller is in a 30x30mm form factor, with the goal of running it under Betaflight. It is for the moment only designed for DJI HD VTX.

** Project status:** This project is currently under development. The schematics are completed and the PCB is being routed.

Main Features

Microcontroller

• STM32H743VITx - ARM Cortex-M7 dual core processor running at 480 MHz
  • 2048 KB Flash memory
  • 1024 KB RAM
  • 82 available GPIOs
  • LQFP100 package

Embedded Sensors

• ICM42688P - Modern IMU (gyroscope + accelerometer)
• MPU6500 - Secondary IMU for redundancy
• QMC5883L - 3-axis magnetometer for compass
• SPL06-001 - Barometer for altitude

Connectivity

• ExpressLRS (ELRS) - Integrated 2.4 GHz RF receiver
  • Dedicated RF_2.4 module
  • Support for long-range and low-latency link
• USB-C - 16-pin USB 2.0 connector for configuration and updates
• HDGC1002WR Connectors - Multiple connectors for peripherals
  • GPS (4 pins)
  • DJI HD VTX (6 pins)
  • Additional UART ports

Power Supply

• Intelligent power management
  • MP9943GQ-z regulator - Main buck converter
  • ME6217C33M5G regulator - 3.3V LDO
  • Support pour batteries LiPo (VBAT)
  • Rails multiples: VDD_MCU, VDD_RECV, 4V5, VDD_GYRO

Storage and LEDs

• Blackbox - SDIO interface for microSD card
  • Flight data logging for analysis
• WS2812 LEDs (addressable) - Programmable visual indicators
• Status LEDs - Multiple LEDs for diagnostics

Project Architecture

The project is organized into distinct hierarchical modules:

Folder Structure
C:.
│   .gitignore
│   fch7.kicad_pcb
│   fch7.kicad_prl
│   fch7.kicad_pro
│   fclib.bak
│   fclib.kicad_sym
│   fp-info-cache
│   fp-lib-table
│   README.md
│   sym-lib-table     
├───Hardware
│   ├───3D
│   │       CSTNE8M00G55Z000R0.stp
│   │       ICM-42688-P.stp
│   │       ME6217C33M5G.step
│   │       MP9943AGQ-Z.stp
│   │       MPU-6500.stp
│   │       STM32H743VIT6.stp
│   │
│   ├───Footprints
│   │   └───fch7_fp.pretty
│   │           AP2112K-1.8TRG1.kicad_mod
│   │           CONN-SMD_HDGC1002WR-S-6P.kicad_mod
│   │           CONN-SMD_HDGC1002WR-S-8P.kicad_mod
│   │           CRYSTAL-SMD_4P-L2.0-W1.6-BL.kicad_mod
│   │           CSNP1GCR01-BOW.kicad_mod
│   │           CSTNE8M00G55Z000R0.kicad_mod
│   │           IIM42352.kicad_mod
│   │           LED0603-R-RD_RED.kicad_mod
│   │           LGA-16_L3.0-W3.0-P0.50-BL_SQ.kicad_mod
│   │           LQFP-100_14x14mm_P0.5mm_STM32H743.kicad_mod
│   │           QFN40P300X300X95-25M-D.kicad_mod
│   │           RES-ARRAY-SMD_0603-8P-L3.2-W1.6-BL.kicad_mod
│   │           SENSOR-SMD_SPL06-001.kicad_mod
│   │           SM03B-SRSS-TB(LF)(SN).kicad_mod
│   │           SolderPad_1x01_SMD_2.2x1.6mm.kicad_mod
│   │           SON65P300X300X100-8N.kicad_mod
│   │           SOT23-5.kicad_mod
│   │           STM32H743VIT6.mod
│   │           SW-SMD_2P-TS24CA.kicad_mod
│   │           TSSOP-28_L9.7-W4.4-P0.65-LS6.4-BL-EP-2.kicad_mod
│   │           USB-C-SMD_TYPE-C-6PIN-2MD-073.kicad_mod
│   │           WIFIM-SMD_ESP-01F-2M.kicad_mod
│   │           WIRELM-SMD_E28-2G4M27SX.kicad_mod
│   └───Symbols
│       └───fch7_sym
│               CSTNE8M00G55Z000R0.bak
│               CSTNE8M00G55Z000R0.kicad_sym
│               fch7_sym.bak
│               fch7_sym.kicad_sym
│               ICM-42688-P.kicad_sym
│               ME6217C33M5G.bak
│               ME6217C33M5G.kicad_sym
│               MP9943AGQ-Z.bak
│               MP9943AGQ-Z.kicad_sym
│               MPU-6500.kicad_sym
│               STM32H743VIT6.kicad_sym
└───Schematic
        blackbox_led.kicad_sch
        connectors.kicad_sch
        ERC.rpt
        fch7.csv
        fch7.kicad_sch
        fp-info-cache
        MCU.kicad_sch
        Power.kicad_sch
        rf_rx.kicad_sch
        sensors.kicad_sch
        ~fch7.kicad_sch.lck

Custom Components

The project uses a custom symbol library (fclib.kicad_sym) containing:

• ICM42688P (IMU)
• MPU6500 (IMU)
• QMC5883L (Magnetometer)
• SPL06-001 (Barometer)
• elrs_rx (RF Modules)
• MP9943GQ-z (Buck converter)
• ME6217C33M5G (LDO)
• Connecteurs HDGC1002WR (4P, 6P, 8P)
• CSNP1GCR01-BOW
• WS2812_ (LEDS)

Applications

This flight controller is designed for:

• Freestyle drones
• Long-range drones
• Stabilized and acrobatic flight applications
• Compatibility with open-source firmwares (Betaflight)

Technical Specifications

Available Interfaces

• SPI - High-speed communication with sensors and OSD
• I2C - Communication with magnetometer and barometer
• UART - Multiple ports for GPS, telemetry, peripherals
• SDIO - SD card interface for blackbox
• PWM/DShot - Motor control (via MCU GPIO)
• USB - Configuration and firmware update

Power Requirements

• Input: LiPo Batteries (2-6S typical)
• Regulated rails: 3.3V, 4.5V, VDD_MCU, VDD_RECV, VDD_GYRO
• Reverse polarity protection

Required Tools

Software

• KiCad 9.0 or higher - Schematic and PCB design
• Git - Version control

Development Roadmap

• MCU schematic
• Power schematic
• Sensors schematic
• RF receiver schematic
• Blackbox/LEDs schematic
• Connectors schematic
• Custom symbol library
• PCB layout
• Track routing
• DRC/ERC verification
• Gerber file generation
• Prototype and testing
• Base firmware
• User documentation

Design Notes

Contribution

This project is under active development. Contributions, suggestions, and feedback are welcome !

Auteur

Maxim - maks7d

Communauté

• ExpressLRS - ExpressLRS Documentation
• KiCad Forum - KiCad Support

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Version: 0.1-alpha
Last Updated: December 2025