Debounce State Machine in C

Medium C FSM Asked at Garmin

Implement a software debouncer for a mechanical push button sampled at a fixed rate. The output must only change after the raw input has been stable for N consecutive samples.

Constraints

Signature: `int debounce_step(int raw)` returning the debounced level.
Stability threshold is 5 consecutive identical samples.
State is held in file-scope statics; no globals exposed in the header.
Initial debounced state is 0.
A glitch shorter than 5 samples must never reach the output.

Starter codeC

1#define STABLE_COUNT 52 3int debounce_step(int raw) {4    // TODO: return the debounced level5    return 0;6}