STM32F411CE INAV Flight Controller

Compact and powerful STM32F411CE based flight controller designed for INAV firmware.

This controller supports multiple IMU sensors and provides essential interfaces for GPS, receivers, ESCs, telemetry and peripherals.

⚠️ Firmware Version Notice

INAV 9.0.1 Update

This documentation is written for INAV 9.0.1 firmware.

The firmware for INAV 9.0.1 has been redesigned and improved for better stability.

⚠️ Important

Pin assignments used in INAV 9.0.1 are different from firmware versions earlier than INAV 9.0.1.

Please make sure you follow the correct documentation for your firmware version.

Firmware Version	Documentation
INAV 9.0.1 and newer	Use this README
Older than INAV 9.0.1	Use README2

Starting from INAV 9.0.1, the pin configuration provided in this document will remain the reference for future firmware releases.

---

⚡ Power Requirements

The flight controller must be powered with a stable 5V DC supply.

Most ESCs include a 5V BEC (Battery Eliminator Circuit) that can be used to power the flight controller.

Power Options

You can power the flight controller using one of the following methods:

1. ESC with built-in 5V BEC
2. External 5V BEC module

If your ESC does not provide a 5V BEC, you must use an external regulated 5V BEC to power the flight controller.

⚠️ Important Warning

• The flight controller must not be powered directly from battery voltage.
• Only use a stable 5V DC supply.

Supplying incorrect voltage may permanently damage the flight controller.

Always verify the output voltage of your BEC before connecting it to the FC.

---

Detailed Diagram

---

SBUS Signal Inverter

The inverter is easy to make, only requires 2 resistors (10K ohm and 4.7K ohm), 1 transistor (BC547b), and one cable. These are all very cheap and easy to find.

---

✈️ Features

• STM32F411CE MCU
• Supported IMU sensors
  • MPU9250
  • MPU6500
  • BMI160
• BMP280 Barometer
• MAX7456 OSD
• 2 Hardware UART ports
• SoftSerial support
• I2C bus for compass and peripherals
• WS2811 LED strip support
• Up to 6 motor outputs
• Additional servo outputs
• Battery voltage monitoring
• Current sensing
• RSSI analog input
• Airspeed sensor input

---

📦 Firmware

This flight controller runs INAV Firmware.

Download firmware: inav_xxx_STM32F411CE.zip

xxx = firmware version number.

Example: inav_9.0.1_STM32F411CE.zip

---

🖥 INAV Configurator

Download the configurator matching the firmware version.

https://github.com/iNavFlight/inav-configurator/releases

Example:

Firmware	Configurator
INAV 9.x	Configurator 9.x

Extract the ZIP file and run: inav-configurator.exe

---

🔌 Enter DFU Mode

To flash firmware, the flight controller must be in DFU mode.

Steps

1️⃣ Locate the BOOT0 button on the board

2️⃣ Press and hold BOOT0

3️⃣ Connect the USB cable to your PC

4️⃣ Release the button

If successful, DFU will appear in the configurator connection menu.

---

⚠ DFU Driver Fix

If DFU does not appear, install drivers using:

https://impulserc.blob.core.windows.net/utilities/ImpulseRC_Driver_Fixer.exe

Run the program and allow it to install the required drivers.

---

💾 Flashing Firmware

1. Open INAV Configurator

2. Go to "Firmware Flasher"

3. Click "Load Firmware [Local]""

4. Select the file "inav_xxx_STM32F411CE.hex"

5. Click "Flash Firmware"

The firmware will start uploading.

---

✅ Successful Installation

If flashing is successful:

• wait a few seconds
• the blue LED will start blinking

🎉 Firmware installed successfully.

---

🧠 Supported IMU Sensors

This board supports the following SPI IMU sensors:

Sensor
MPU9250
MPU6500
BMI160

---

📍 Pinout

---

🧭 IMU (SPI)

Signal	Pin
SCK	PB13
MISO	PB14
MOSI	PB15
CS	PB12

---

🌡 Barometer (BMP280)

Signal	Pin
CS	PC15

---

📺 OSD (MAX7456)

Signal	Pin
CS	PC14

---

⭐ I2C Supported IMU Sensors

ALL Barometer, All Compass sensors.

🔗 I2C

Signal	Pin
SCL	PB8
SDA	PB9

---

🔔 Beeper

Function	Pin
Beeper	PB2

---

🔌 UART Ports

UART1

Function	Pin
TX	PA15
RX	PB3

---

UART2

Function	Pin
TX	PA2
RX	PA3

---

🔌 Wiring Guide

UART1 GPS Connection

GPS	Flight Controller
TX	RX (UART) PB3 Pin
RX	TX (UART) PA15 Pin
5V	5V
GND	GND

---

UART2 Receiver Connection

SBUS /iBUS

Receiver	FC	FC Pin
Signal	RX	PA3 Pin
5V	5V	External 5V
GND	GND	Common GND

CRSF / ELRS

Receiver	FC	FC Pin
TX	RX	PA3 Pin
RX	TX	PA2 Pin
5V	5V	External 5V
GND	GND	Common GND

---

ESC Connection

ESC	FC
Signal	Motor Pin PB4
Signal	Motor Pin PB5
Signal	Motor Pin PB0
Signal	Motor Pin PB1
5V	BEC
GND	GND

---

🧵 SoftSerial

Function	Pin
TX	PA0
RX	PA1

---

⚡ ADC Inputs

Function	Pin
VBAT	PA4
Current Meter	PA5
RSSI	PA6
Airspeed	PA7

---

💡 LED Strip

Function	Pin
WS2811 LED	PB10

---

🌀 Motor Outputs

Motor	Pin
Motor1	PB4
Motor2	PB5
Motor3	PB0
Motor4	PB1
Motor5 / Servo	PB6
Motor6 / Servo	PB7

---

🎮 Servo Outputs

Servo	Pin
Servo1	PA8
Servo2	PA9
Servo3	PA10

---

⚙ Recommended Setup Steps

After flashing firmware:

1. Calibrate accelerometer
2. Calibrate compass
3. Configure receiver
4. Configure motor outputs
5. Setup GPS (if used)
6. Setup flight modes

---

🔗 Useful Links

INAV Official Website

https://inavflight.com

INAV GitHub

https://github.com/iNavFlight

INAV Documentation

https://github.com/iNavFlight/inav/wiki

---

📜 License

This project is open-source and intended to support the INAV ecosystem.

---

❤️ Acknowledgements

Special thanks to the INAV community and developers for their continuous work on the firmware.