Overview

The GPIO parameter group (specifically GPIO_MASK or SERVO_GPIO_MASK) configures the repurposing of motor/servo outputs for General Purpose Input/Output (GPIO) functions.

By default, the pins on your flight controller's servo rail are configured to output high-frequency PWM or DShot signals for motors. This group allows you to "re-task" some of those pins to be simple on/off digital switches (3.3V high/low).

Key Concepts

1. Servo to GPIO Mapping

Pins are assigned using a bitmask. When a bit is set for a specific output channel, the PWM timer for that pin is disabled, and it is handed over to the GPIO controller.

• Common Uses:
  • Controlling a Relay.
  • Firing a Camera Shutter.
  • Toggling external LED strips.
  • Input for a push-button (see BTN group).

Parameter Breakdown

• GPIO_MASK: Bitmask of pins to convert to GPIO.
  • Bit 0: Servo 1.
  • Bit 5: Servo 6.
  • Value 32 (2^5): Converts AUX 1 (on many boards) to GPIO.

Integration Guide

1. Select Pin: Identify which servo pin you want to use.
2. Enable: Set the corresponding bit in GPIO_MASK.
3. Assign Function: Use RELAY_PIN or CAM_FEEDBAK_PIN to reference the digital ID of that pin.

Developer Notes

• Library: libraries/SRV_Channel.
• Hardware: Not all pins on all boards can be converted (depends on the microcontroller's timer allocation). Refer to your board's "Mapping" page on the ArduPilot Wiki.