Heewing FX-405 Flight Controller Instruction Manual

Specifications

• STM32F405 Microcontroller
• ICM42688 IMU
• SLP06 barometer
• Dataflash (V2 board only)
• MAX7456 OSD
• 4 UARTS
• 9 PWM outputs
• FC Input Voltage: 5V
• PMU Input Voltage: 7.4V to 22.2V
• FC Dimension: 44.3mm (L) x 34.4mm (W) x 13.7mm (H)
• FC Weight: 14.2gram (without PMU & wires)

PMU:

FX-405 Flight Controller:

GPS Module:

USB Adapter

PMU to FC Cable

Other Cables for connecting VTX, Camera & etc

1. Connecting Receiver

Connect your preferred receiver to the RC-In Port on the flight controller.

Supported Receiver Types

a. SBUS, IBUS, PPM Receiver

Factory parameters are pre-configured for this type of receiver, and the flight controller will auto-recognize the signal type.

• BRD_ALT_Config = 0
• SERIAL6_PROTOCOL = -1

b. ELRS & CRSF Receiver

Set the parameters below, then "write params" to the flight controller and reboot.

• BRD_ALT_Config = 1
• SERIAL6_PROTOCOL = 23

For SBUS Receiver:

For ELRS/CRSF Receiver:

2. Setting Failsafe

It is important to set your receiver failsafe setting accordingly. Refer to your receiver manual and verify that the intended failsafe setting is correct before flight (e.g., flight controller going into RTL mode when the radio is off/signal lost).

*Have propeller removed when testing this.

In the case of VTOL enabled FC, the plane will go into fixed wing mode and transition into VTOL mode during landing at the home position.

3. Starting the Motors

The flight controller is set to disarm the motors during every reboot. To disarm/unlock the motors, hold full rudder right for about 4 seconds.

As ARMING_CHECK=0 is set to zero, there are no arming conditions checked by the flight controller before the motors are disarmed. Ensure that you have GPS Home locked and sensors are all ready.

To disarm or stop the motors spinning: Hold full rudder left for about 4 seconds.

Note: Motors will go into idle mode/spinning slowly when disarmed. Please takeoff the propellers when testing this for the first time.

4. Serial Interface

• Serial interface 1: default Mavlink 1
• Serial interface 2: default Mavlink 2

5. IIC

Default: ASP5033

6. Setting Up for Digital FPV

For new Avatar / SharkByte / DJI O3 (MSP Display Port)

Method 1 - using UART1 or UART2

• Set the below parameters:
  OSD TYPE = 3
  SERIAL2_PROTOCOL = 33 (or SERIAL1_PROTOCOL = 33)
  MSP_OPTIONS = 0 (or use 4 or 5 if there's font incompatibility)
• Connect your Air Unit RX & TX to the TX & RX on the UART1 or UART2.
• Power your Air Unit from the 9V from the VTX or CAM port on the flight controller.

To enable Auto Recording after arming the motors: Go to your DJI Goggle Settings > Recording Settings > Takeoff REC, set to ON.

7. MSP OSD Protocol

For the old DJI Google V1 & V2

• Use UART1 or UART2
• Set the below parameters:
  OSD_TYPE = 3
  SERIAL2_PROTOCOL = 33 (or SERIAL1...)
  MSP_OPTIONS = 0
• Have RX & TX connected to either UART1 or UART2 and power it from the 9V of VTX or CAM port on the FC.
• DJI OSD must be enabled on your goggles. Go to Settings > Display > Custom OSD.

Optional: You may set OSD_TYPE to 1 to output both analog OSD and MSP OSD.

8. First Flight Preparation

1. Create a new model in your Radio, set up a 3-position switch on Channel 6 for flight modes.
2. Connect your flight controller to Mission Planner, perform Accelerometer Calibration and Radio Calibration.
3. Before your first flight, ensure there is GPS HOME lock and control surfaces are moving at the correct directions.
4. Switch flight mode to QLoiter, hold full Right Rudder for about 4 seconds to Arm the motors. The motors will start to spin slowly. Increase the throttle gradually to take off.
5. Push your sticks to confirm Pitch, Roll, and Rudder are reacting to the correct direction.
6. Raise your altitude and switch to FBWA mode for forward flying.

9. Flight Controller Pin-out

Pinout Diagram:

I2C: Blank

USB: to PC

UART 1: Digital VTX

VTX: Analog VTX

CAM: to Analog Camera

UART 2: Digital VTX

PMU:

GPS:

Pin Assignments:

• S1 Aileron servo (Y cable)
• S2 Elevator servo
• S3 UBEC
• S4 Blank
• S5 Left tilt servo
• S6 Right tilt servo
• S7 Left motor
• S8 Right motor
• S9 Rear motor
• RC-IN Receiver

*Above connection is for T1 Ranger VTOL. You may change it based on your own configuration on other planes.

10. PMU Connection

PMU Connection Diagram

Input: 2~6S

Output to Rear ESC

11. Master Wiring

Wiring Diagram showing connections for SBUS or ELRS/CRSF receivers, servos, motors, GPS, and PMU to the FX-405 Flight Controller.

Pin Assignments:

• S1 Aileron servo(Y cable)
• S2 Elevator servo
• S3 UBEC
• S4 Blank
• S5 Left tilt servo
• S6 Right tilt servo
• S7 Left motor
• S8 Right motor
• S9 Rear motor
• RC-IN Receiver

Mission Planner Configuration

1. Visit www.heewing.com for the latest instruction manual and build video.
2. Download the latest Mission Planner from this link.
3. Open Mission Planner after installation. Connect your flight controller to your PC via the USB adapter and a USB C cable.
4. Choose the correct Com Port from the dropdown menu on the top left and click "Connect".

Mission Planner Interface Screenshot: Shows the flight controller connected, indicating "DISARMED" status, altitude, ground speed, and GPS status.

If you are using SBUS, IBUS or PPM, your receiver signal is automatically recognised by the flight controller. No action is needed in this step.

If you are using ELRS or CRSF, go to CONFIG > Full Parameter List > configure the following parameters:

• BRD_ALT_Config = change the value to 1
• SERIAL6_PROTOCOL = change the value 23

*The receiver is not powered via USB; you need to connect your flight battery.

On your preferred Radio, set a 3-position switch to Channel 6.

Go to Setup > Mandatory Hardware > Radio Calibration > Click Calibrate Radio and follow the step-by-step instructions shown on the screen.

Radio Calibration Screen: Displays Roll, Pitch, Yaw, and Throttle inputs, with options to calibrate and bind.

Then go to Flight Modes.

Toggle your 3-position switch. You should see the flight modes change between QLOITER (FM1), FBWA (FM4), & QRTL (FM6).

Flight Modes Screen: Shows Flight Mode 1 set to QLOITER, Flight Mode 2 to RTL, Flight Mode 3 to FBWA, Flight Mode 4 to FBWB, Flight Mode 5 to Manual, and Flight Mode 6 to QRTL.

With the propellers off, power up your VTOL plane and perform preflight checks such as control surface direction, VTOL controls, and flight modes.

WARNING

Although extensive testing and tuning has been done, the provided VTOL parameters are for your reference only. Heewing RC does not take responsibility for any issue arising from this. Adjust parameters accordingly to your flying environment or requirement.

Respect the rules of your local flying site or flying club. Choose an appropriate flying site, vast open space, and stay away from people and property.

Ensure that everything has been setup correctly before flying. Heewing RC is not liable for any issues arising from factors beyond our control.