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

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#include <avr/io.h>
#include <stdbool.h>
#include "debounce.h"
#include "calc.h"
#include "pins.h"
#include "debo_config.h"
/** Debounce data array */
uint8_t debo_next_slot = 0;
uint8_t debo_register(PORT_P reg, uint8_t bit, bool invert)
{
debo_slots[debo_next_slot] = (debo_slot_t){
.reg = reg,
.bit = bit | ((invert & 1) << 7) | (get_bit_p(reg, bit) << 6), // bit 7 = invert, bit 6 = state
.count = 0,
};
return debo_next_slot++;
}
/** Check debounced pins, should be called periodically. */
void debo_tick()
{
for (uint8_t i = 0; i < debo_next_slot; i++) {
// current pin value (right 3 bits, xored with inverse bit)
bool value = get_bit_p(debo_slots[i].reg, debo_slots[i].bit & 0x7);
if (value != get_bit(debo_slots[i].bit, 6)) {
// different pin state than last recorded state
if (debo_slots[i].count < DEBO_TICKS) {
debo_slots[i].count++;
} else {
// overflown -> latch value
set_bit(debo_slots[i].bit, 6, value); // set state bit
debo_slots[i].count = 0;
}
} else {
debo_slots[i].count = 0; // reset the counter
}
}
}