The Pixhawk has 14 servo output channels which are configured via the SERVOn_* parameters and the BRD_PWM_COUNT parameter.
| Pixhawk Label | Servo Channel |
|---|---|
| Main 1 | 1 |
| Main 2 | 2 |
| Main 3 | 3 |
| Main 4 | 4 |
| Main 5 | 5 |
| Main 6 | 6 |
| Main 7 | 7 |
| Main 8 | 8 |
| Aux 1 | 9 |
| Aux 2 | 10 |
| Aux 3 | 11 |
| Aux 4 | 12 |
| Aux 5 | 13 |
| Aux 6 | 14 |
The Pixhawk has 6 ‘auxiliary’ outputs that can be configured as either general purpose input/output or PWM output.
The auxiliary pins are configured at boot according to the BRD_PWM_COUNT parameter.
| BRD_PWM_COUNT <td colspan=6> Aux pin configuration | ||||||
|---|---|---|---|---|---|---|
| 1 | 2 | 3 | 4 | 5 | 6 | |
| 0 | GPIO | GPIO | GPIO | GPIO | GPIO | GPIO |
| 2 | PWM | PWM | GPIO | GPIO | GPIO | GPIO |
| (default) 4 | PWM | PWM | PWM | PWM | GPIO | GPIO |
| 6 | PWM | PWM | PWM | PWM | PWM | PWM |
An output must be configured as PWM via the BRD_PWM_COUNT parameter to operate a servo.
The servos can be operated via the mavlink command DO_SET_SERVO. This command can be used to set the output of any servo channel that is not configured as a motor output. This command can conflict with other functions operating on the servo channel like pan/tilt mounts or lights. In order to avoid conflicts, the corresponding SERVOn_FUNCTION parameter should be set to Disabled (0).
Up to three servos can also be operated via joystick button functions. The joystick button functions for *_servo_n will control the output on the Aux n pin (these cannot be remapped like the relay outputs).
| Joystick button function | Aux channel operated |
|---|---|
| servo_1 | Aux 1 |
| servo_2 | Aux 2 |
| servo_3 | Aux 3 |
ArduSub supports control of up to 4 relays. An output must be configured as GPIO via the BRD_PWM_COUNT parameter to operate a relay. The output pin must also be selected for the corresponding RELAY_PIN parameter.
The relays can be operated via the mavlink command DO_SET_RELAY.
Up to three relays can also be operated via joystick button functions.