3.1 KiB
Pixhawk4-Mini Flight Controller
The Pixhawk4-Mini flight controller is sold by Holybro
Features
- STM32F765 microcontroller
- Two IMUs: ICM20689 and BMI055
- MS5611 SPI barometer
- builtin SPI IST8310 magnetometer
- microSD card slot
- 3 UARTs plus USB
- 8 PWM outputs
- Two I2C and one CAN ports
- External Buzzer
- external safety Switch
- dedicated power input port for external power bricks
Pinout
UART Mapping
- SERIAL0 -> USB
- SERIAL1 -> UART2 (Telem1)
- SERIAL2 -> UART3 (Telem2)
- SERIAL3 -> UART1 (GPS)
- SERIAL6 -> UART7 (debug)
The Telem1 and Telem2 ports have RTS/CTS pins, the other UARTs do not have RTS/CTS.
The UART7 connector is inside the case and labelled as debug, but is available as a general purpose UART with ArduPilot.
RC Input
RC input is configured on the port marked RC IN. This connector supports all RC protocols. Two cables are available for this port. To use software binding of Spektrum satellite receivers you need to use the Spektrum satellite cable.
PWM Output
The Pixhawk4-Mini supports up to 8 PWM outputs. All 8 outputs support all normal PWM output formats. Only the first 6 outputs support DShot.
The 8 auxillary PWM outputs are in 3 groups:
- PWM 1, 2, 3 and 4 in group1
- PWM 5 and 6 in group2
- PWM 7 and 8 in group3
Channels within the same group need to use the same output rate. If any channel in a group uses DShot then all channels in the group need to use DShot.
Battery Monitoring
The board has two dedicated power monitor ports on 6 pin connectors. The correct battery setting parameters are dependent on the type of power brick which is connected.
Compass
The Pixhawk4-Mini has a builtin IST8310 compass. Due to potential interference the board is usually used with an external I2C compass as part of a GPS/Compass combination.
GPIOs
The 8 PWM ports can be used as GPIOs (relays, buttons, RPM etc). To use them you need to limit the number of these pins that is used for PWM by setting the BRD_PWM_COUNT to a number less than 8. For example if you set BRD_PWM_COUNT to 6 then PWM6 and PWM7 will be available for use as GPIOs.
The numbering of the GPIOs for PIN variables in ArduPilot is:
- PWM1 50
- PWM2 51
- PWM3 52
- PWM4 53
- PWM5 54
- PWM6 55
- PWM7 56
- PWM8 57
In addition there are 4 pins on the servo rail marked CAP1 to CAP4. The first 3 of these are available as GPIOs in ArduPilot using the following GPIO numbers:
- CAP1 58
- CAP2 59
- CAP3 60
Analog inputs
The Pixhawk4-Mini has 4 analog inputs
- ADC Pin0 -> Battery Voltage
- ADC Pin1 -> Battery Current Sensor
- ADC Pin10 -> ADC 5V Sense
- ADC Pin11 -> ADC 3.3V Sense
Loading Firmware
The board comes pre-installed with an ArduPilot compatible bootloader, allowing the loading of *.apj firmware files with any ArduPilot compatible ground station.
Acknowledgements
Thanks to PX4 for images used under the CC-BY 4.0 license