libraries/AP_HAL_ChibiOS/hwdef/MatekH7A3-Wing/README.md
The UARTs are marked Rx and Tx in the above pinouts. The Rx pin is the receive pin for UARTx. The Tx pin is the transmit pin for UARTx.
H7A3-SLIM supports 1x CAN bus and 1x I2C bus multiple CAN peripherals can be connected to one CAN bus in parallel. similarly for I2C bus.
RC input is configured on the USART2(SERIAL2). It supports all serial RC protocols. SERIAL2_PROTOCOL=23 by default.
H7A3-SLIM supports using its internal OSD using OSD_TYPE 1 (MAX7456 driver). External OSD support such as DJI or DisplayPort is supported using any spare UART. See :ref:common-msp-osd-overview-4.2 for more info.
H7A3-SLIM supports up to 11 PWM outputs. All outputs support DShot. The PWM is in 5 groups:
The board has 2x built-in voltage dividers and 2x current ADC. support external 3.3V based current sensor
The correct battery setting parameters are set by default and are:
BATT_MONITOR 4
BATT_VOLT_PIN 10
BATT_CURR_PIN 11
BATT_VOLT_MULT 21.0 ("Vbat" pad support 5.5~30V input, limited by onboard regulator chips)
BATT_AMP_PERVLT X ("Curr" pad, set it according to external current sensor spec)
BATT2_VOLT_PIN 18
BATT2_CURR_PIN 8
BATT2_VOLT_MULT 21.0 ("VB2" pad support Max.69V voltage sense)
BATT_AMP_PERVLT X ("CU2" pad, set it according to external current sensor spec)
H7A3-SLIM does not have a built-in compass, but you can attach an external compass using I2C on the SDA and SCL pads.
GPIO 81 controls the 9V BEC output to pins marked "9V". Setting this GPIO high removes voltage supply to pins. Default GPIO 81 is low(9V output enable)
Firmware for these boards can be found at the ArduPilot firmware server in sub-folders labeled MatekH7A3-Wing.
Initial firmware load can be done with DFU by plugging in USB with the boot button pressed. Then you should load the "ardu*_with_bl.hex" firmware, using your favourite DFU loading tool. eg STM32CubeProgrammer
Subsequently, you can update firmware with Mission Planner.