Buttons

Button Press Detection Mechanism

The button press detection mechanism in the 3-key project involves several key components and processes to ensure accurate detection of both short and long presses. This document describes the overall mechanism, including debouncing and long press detection.

Short Press Detection

When a button is pressed, an interrupt is triggered, and the gpio_callback function is called. This function checks if the button is already debouncing or pending handling. If not, it starts a debounce timer to filter out any noise or false triggers.

Debouncing

Debouncing is the process of filtering out noise or false triggers that can occur when a button is pressed or released. The debounce timer ensures that the button state is stable before considering it as a valid press.

Long Press Detection

Long press detection involves starting a long press timer after the debounce timer confirms a valid press. The long press timer periodically checks if the button is still pressed. If the button remains pressed for a duration longer than the configured long press delay, it is considered a long press.

Summary

• Short Press Detection: Triggered by an interrupt, followed by a debounce timer to confirm the press.
• Debouncing: Filters out noise and false triggers to ensure a stable button state.
• Long Press Detection: Starts a long press timer after debouncing, periodically checks the button state, and confirms a long press if the button remains pressed for the configured duration.

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