porklib: Simple library for programming Arduino in C
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avr-lib/lib/debounce.h

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1.7 KiB

#pragma once
//
// An implementation of button debouncer.
//
// ----
//
// You must provide a config file debo_config.h (next to your main.c)
//
// Example:
// #pragma once
// #define DEBO_CHANNELS 2
// #define DDEBO_TICKS 5
//
// ----
//
// A pin is registered like this:
//
// #define BTN1 B,0
// #define BTN2 B,1
//
// debo_add(BTN0); // The function returns number assigned to the pin (0, 1, ...)
// debo_add_rev(BTN1); // active low
// debo_register(&PINB, PB2, 0); // direct access - register, pin & invert
//
// Then periodically call the tick function (perhaps in a timer interrupt):
//
// debo_tick();
//
// To check if input is active, use
//
// debo_get_pin(0); // state of input #0 (registered first)
// debo_get_pin(1); // state of input #1 (registered second)
//
#include <avr/io.h>
#include <stdbool.h>
#include "calc.h"
#include "pins.h"
#include "debo_config.h"
/* Internal deboucer entry */
typedef struct {
PORT_P reg; // pointer to IO register
uint8_t bit; // bits 6 and 7 of this hold "state" & "invert" flag
uint8_t count; // number of ticks this was in the new state
} debo_slot_t;
debo_slot_t debo_slots[DEBO_CHANNELS];
/** Add a pin for debouncing */
#define debo_add_rev(io) debo_register(&io2pin(io_pack(io)), io2n(io_pack(io)), 1)
#define debo_add(io) debo_register(&io2pin(io_pack(io)), io2n(io_pack(io)), 0)
/** Add a pin for debouncing (low level function) */
uint8_t debo_register(PORT_P pin_reg_pointer, uint8_t bit, bool invert);
/** Check debounced pins, should be called periodically. */
void debo_tick();
/** Get a value of debounced pin */
#define debo_get_pin(i) (get_bit(debo_slots[i].bit, 6) ^ get_bit(debo_slots[i].bit, 7))