KiwiH743 12S Flight Controller

Overview

The KiwiH743 is a high-performance flight controller based on the STM32H743 MCU, designed for advanced UAV applications. It combines powerful processing, flexible connectivity, and rich sensor support, optimized for ArduPilot firmware.

It is the next generation of the KiwiF405 family, offering 2MB flash, 480 MHz CPU clock, extended UART/SPI/I2C buses, and support for dual IMUs, barometer, and OSD integration.

Premium features: GPS-less takeoff, IRC Tramp VTX control, VRX integration (TBS Fusion, Skyzone Steadyview).

Firmware

ArduPilot KiwiH743.zip
ArduPilot (SD card) KiwiH743-sdcard.zip
Betaflight

Features

Dual IMUs: ICM-42688P + ICM-45686 with EKF3 dual-source fusion
BMP388 barometer, external compass support (I²C probing)
Integrated OSD (MAX7456-compatible via SPI4)
14 PWM outputs (8 motors + 6 servos), DShot bidirectional on M1–M4
7 hardware UARTs + 2 USB ports (OTG1 MAVLink, OTG2 HiSpeed serial)
16 MB DataFlash + external SD card slot
Visual odometry, external AHRS, GPS moving baseline support
Gyro FFT for vibration analysis
INS temperature calibration
Guided (NoGPS), FlowHold, OpticalFlow modes

Technical Specifications

MCU: STM32H743VIT6 (ARM Cortex-M7, 480 MHz, 2048 KB flash)
Crystal: 16 MHz external oscillator
IMU1: ICM-42688P (SPI6, rotation YAW_180)
IMU2: ICM-45686 (SPI2, rotation YAW_270)
Barometer: BMP388 (I2C2, address 0x76)
OSD: MAX7456-compatible (SPI4)
DataFlash: 16 MB (SPI3)
LED: PE4 (active low)
Dimensions: 36×36 mm, mounting 30.5×30.5 mm

Serial Ports

Port	ArduPilot	Default Protocol	Pins	Notes
USB	SERIAL0	MAVLink	PA11, PA12	OTG1 Full Speed
USART1	SERIAL1	ESC Telemetry (115200)	PA10	RX only
USART2	SERIAL2	SmartAudio (115200)	PD5, PD6	NODMA
USART3	SERIAL3	—	PD8, PD9
UART4	SERIAL4	—	PD1, PD0
UART5	SERIAL5	MAVLink1 (57600)	PB6, PD2	NODMA
UART7	SERIAL7	MAVLink2	PE8, PE7	RTS: PE9, CTS: PE10
UART8	SERIAL8	RC Input	PE1, PE0	SBUS/DSM
USB HS	SERIAL9	—		OTG2 HiSpeed

RC input: SBUS/DSM on PE11.

GPIOs, Relays, and AUX

Dedicated GPIO Pads

Pad	Pin	GPIO	Default	ArduPilot Relay Config
CAM SW	PA8	100	RELAY1	`RELAY1_PIN=100` (hwdef default)
RELAY1	PD4	101	Output LOW	`RELAY2_PIN=101`, `RELAY2_FUNC=1`
RELAY2	PB7	102	Output LOW	`RELAY3_PIN=102`, `RELAY3_FUNC=1`
LED	PE4	90	Status LED	—

Note: RELAY1_PIN defaults to GPIO 100 (Camera Switch pad, PA8), not the pad labeled “RELAY1” (PD4, GPIO 101). This is set in the hwdef. Adjust if your wiring differs.

PWM Outputs

Output	Pin	GPIO	Timer	Function	DShot Bidir
PWM1	PC6	50	TIM3_CH1	Motor 1	Yes
PWM2	PC7	51	TIM3_CH2	Motor 2	Yes
PWM3	PC8	52	TIM3_CH3	Motor 3	Yes
PWM4	PC9	53	TIM3_CH4	Motor 4	Yes
PWM5	PD12	54	TIM4_CH1	Motor 5	No
PWM6	PD13	55	TIM4_CH2	Motor 6	No
PWM7	PD14	56	TIM4_CH3	Motor 7	No
PWM8	PD15	57	TIM4_CH4	Motor 8	No
PWM9	PA0	58	TIM5_CH1	Servo 1	No
PWM10	PA1	59	TIM5_CH2	Servo 2	No
PWM11	PA2	60	TIM5_CH3	Servo 3	No
PWM12	PA3	61	TIM5_CH4	Servo 4	No
PWM13	PE13	62	TIM1_CH3	Servo 5	No
PWM14	PB8	63	TIM16_CH1	Servo 6	No

PWM pins can be reassigned to GPIO via SERVOn_FUNCTION=0 + RELAYn_PIN=<gpio>.

Spare ADC

Pin	Function
PC1	SPARE2_ADC1 (analog input only)

Relay Usage

MAVProxy:

param set RELAY2_PIN 101
param set RELAY2_FUNC 1
relay set 0 1    # RELAY1 ON (CAM SW pad HIGH)
relay set 0 0    # RELAY1 OFF
relay set 1 1    # RELAY2 ON (RELAY1 pad HIGH)

Mission waypoint: DO_SET_RELAY — relay number 0-based (0=RELAY1), setting 1=ON / 0=OFF.

Lua:

relay:toggle(0)  -- toggle RELAY1 (CAM SW)
relay:on(1)      -- RELAY2 ON (RELAY1 pad)
relay:off(1)     -- RELAY2 OFF

All GPIO pads default LOW on boot. Use RELAY_DEFAULT params to set initial state.

Power Monitoring

Battery Voltage: PC5 (ADC1 IN8)
Battery Current: PB1 (ADC1 IN5)
Default monitor type: Analog

Sensor Calibration

Parameter	ArduPilot	Betaflight
Voltage scale	`BATT_VOLT_MULT` = 21.0	`voltage_meter_scale` = 210
Current scale	`BATT_AMP_PERVLT` = 142.9	`current_meter_scale` = 100

Battery Voltage Thresholds (ArduPilot)

Parameter	6S	8S	12S
Full charge	25.2 V	33.6 V	50.4 V
`BATT_ARM_VOLT`	22.2	29.6	44.4
`BATT_LOW_VOLT`	21.0	28.0	42.0
`BATT_CRT_VOLT`	19.8	26.4	39.6

Buses

SPI

Bus	CLK	MISO	MOSI	Usage
SPI1	PA5	PA6	PA7	SD Card (CS: PA4)
SPI2	PB13	PB14	PB15	IMU2 ICM-45686 (CS: PD10)
SPI3	PC10	PC11	PC12	DataFlash (CS: PD3)
SPI4	PE2	PE5	PE6	OSD MAX7456 (CS: PE3)
SPI6	PB3	PB4	PB5	IMU1 ICM-42688P (CS: PC13)

I2C

Bus	SCL	SDA	Devices
I2C2	PB10	PB11	BMP388 (0x76), external compass

Default Frame and Modes

Default frame: Quadcopter X (FRAME_TYPE=3, BetaFlight-X motor order)
Motor protocol: DShot (MOT_PWM_TYPE=5)
BLHeli passthrough: enabled (SERVO_BLH_AUTO=1, mask=15)
Flight mode channel: CH8
VTX: enabled, band 6, channel 4

Camera Gimbal Support

KiwiH743 supports camera gimbals out of the box — both servo-based and MAVLink protocol gimbals (CADDX GM3 V2 and compatible).

MAVLink Gimbal

Wire gimbal UART to any free serial port (gimbal TX → FC RX, gimbal RX → FC TX, GND).

Param	Value	Notes
`SERIALx_PROTOCOL`	2	MAVLink2
`SERIALx_BAUD`	115	115200 bps
`MNT1_TYPE`	6	Gremsy (reboot after setting)
`MNT1_PITCH_MIN`	-120	GM3 V2 spec: ±120°
`MNT1_PITCH_MAX`	120
`MNT1_YAW_MIN`	-160	GM3 V2 spec: ±160°
`MNT1_YAW_MAX`	160
`MNT1_RC_RATE`	60	deg/s for rate control, 0 for angle

RC Control

Assign RC channels to control gimbal axes:

Param	Value	Notes
`RC6_OPTION`	213	Mount1 Pitch
`RC7_OPTION`	214	Mount1 Yaw
`RC8_OPTION`	212	Mount1 Roll (3-axis gimbals only)

Example: with MNT1_RC_RATE=60, moving the RC6 stick deflects pitch at 60°/s. Set MNT1_RC_RATE=0 for direct angle control (stick position = gimbal angle).

Gimbal firmware must be V2.0 or higher.

Servo Gimbal

Connect pitch/yaw servos to any Servo PWM outputs (PWM9–PWM14).

Param	Value	Notes
`MNT1_TYPE`	1	Servo
`SERVOx_FUNCTION`	6	Mount1 Pitch (assign to desired output)
`SERVOx_FUNCTION`	8	Mount1 Yaw (assign to desired output)
`MNT1_PITCH_MIN`	-90
`MNT1_PITCH_MAX`	90
`MNT1_YAW_MIN`	-170
`MNT1_YAW_MAX`	170
`MNT1_RC_RATE`	60	deg/s for rate control, 0 for angle

Pinout Reference

ESC Pins

1 - ESC Telemetry
2 - ESC Current
3 - Motor4
4 - Motor3
5 - Motor2
6 - Motor1
7 - VBAT
8 - GND

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