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105 lines
2.5 KiB
105 lines
2.5 KiB
10 years ago
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#pragma once
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/**
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An implementation of button debouncer.
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First, the system must be initialized - even before including:
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#define DEBO_CHANNELS 2
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#define DEBO_TICKS 5
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#inclue "lib/debounce.h"
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A pin is registered like this:
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#define BTN1 B,0
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#define BTN2 B,1
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debo_add(BTN0); // The function returns number assigned to the pin (0, 1, ...)
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debo_add_rev(BTN1); // active low
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debo_register(&PINB, PB2, 0); // direct access - register, pin & invert
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Then periodically call the tick function (perhaps in a timer interrupt):
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debo_tick();
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To check if input is active, use
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debo_get_pin(0); // state of input registered as #0
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debo_get_pin(1); // state of input registered as #1
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*/
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#include <avr/io.h>
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#include <stdbool.h>
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#include "calc.h"
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#include "pins.h"
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// Number of pins to debounce
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#ifndef DEBO_CHANNELS
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# error "DEBO_CHANNELS not defined!"
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#endif
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#ifndef DEBO_TICKS
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# warning "DEBO_TICKS not defined, defaulting to 5!"
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# define DEBO_TICKS 5
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#endif
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/* Internal deboucer entry */
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typedef struct {
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PORT_P reg;
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uint8_t bit;
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uint8_t count;
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} debo_slot_t;
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/** Debounce data array */
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debo_slot_t debo_slots[DEBO_CHANNELS];
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uint8_t debo_next_slot = 0;
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/** Define a debounced pin (must be IO!) */
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#define debo_add_rev(io) debo_register(&io2pin(io_pack(io)), io2n(io_pack(io)), 1)
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#define debo_add(io) debo_register(&io2pin(io_pack(io)), io2n(io_pack(io)), 0)
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uint8_t debo_register(PORT_P reg, uint8_t bit, bool invert)
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{
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debo_slots[debo_next_slot] = (debo_slot_t){
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.reg = reg,
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.bit = bit | ((invert & 1) << 7) | (get_bit_p(reg, bit) << 6), // bit 7 = invert, bit 6 = state
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.count = 0,
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};
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return debo_next_slot++;
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}
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/** Check debounced pins, should be called periodically. */
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void debo_tick()
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{
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for (uint8_t i = 0; i < debo_next_slot; i++) {
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// current pin value (right 3 bits, xored with inverse bit)
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bool value = get_bit_p(debo_slots[i].reg, debo_slots[i].bit & 0x7);
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if (value != get_bit(debo_slots[i].bit, 6)) {
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// different pin state than last recorded state
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if (debo_slots[i].count < DEBO_TICKS) {
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debo_slots[i].count++;
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} else {
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// overflown -> latch value
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set_bit(debo_slots[i].bit, 6, value); // set state bit
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debo_slots[i].count = 0;
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}
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} else {
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debo_slots[i].count = 0; // reset the counter
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}
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}
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}
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/** Get a value of debounced pin */
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#define debo_get_pin(i) (get_bit(debo_slots[i].bit, 6) ^ get_bit(debo_slots[i].bit, 7))
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//(get_bit(debo_slots[i].bit, 6) ^ get_bit(debo_slots[i].bit, 7))
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