webradio/firmware/input.c

#include <avr/io.h>
#include <util/delay.h>
#include <avr/interrupt.h>
#include "input.h"
#include "systick.h"

static volatile uint8_t rotary_delta = 0;
static volatile uint8_t sw_event = 0;

void input_init()
{
	PORT_ROTARY(DDR) &= ~(PIN_ROTARY_A | PIN_ROTARY_B); // Configure as input
	PORT_ROTARY(PORT) |= (PIN_ROTARY_A | PIN_ROTARY_B); // Set pullups

	PORT_KEYPAD(DDR) &= ~(PIN_KEYPAD_MASK); // Key inputs
	PORT_KEYPAD(PORT) |= PIN_KEYPAD_MASK; // Key pullups

	PORT_SBCMON(DDR) &= ~PIN_SBCMON;
	PORT_SBCMON(PORT) |= PIN_SBCMON;
}

inline uint8_t get_rotary_delta()
{
	return rotary_delta;
}

#define ROTARY_DEBOUNCE 150
static inline void input_proc_rotary()
{
	static int8_t last_a;
	int8_t a;
	int8_t b;
	int8_t p;
	uint8_t silly_debounce = 0;

	if (silly_debounce == 0) {
		p = PORT_ROTARY(PIN);
		a = (p & PIN_ROTARY_A);
		b = (p & PIN_ROTARY_B);
		a = !a;
		b = !b;

		if (a == 1 && last_a == 0) {
			silly_debounce = ROTARY_DEBOUNCE;
			if (rotary_delta < 31)
				rotary_delta += !!(a ^ b);
		}
		if (a == 0 && last_a == 1) {
			silly_debounce = ROTARY_DEBOUNCE;
			if (rotary_delta > 0)
				rotary_delta -= !(a ^ b);
		}

		last_a = a;
	} else {
		silly_debounce--;
	}
}

// TODO: Pressing two keys at the same time can lead to unfortunate behavior.
void input_proc_switches()
{
	uint8_t sw;
	uint8_t ev;
	uint8_t i;
	static uint8_t sw_last = 0xFF;

	sw = PORT_KEYPAD(PIN) & PIN_KEYPAD_MASK;
	ev = sw ^ sw_last;

	if (ev) {
		if (timer_expired(TIMID_SW_DEBOUNCE)) { // If we read a value, wait for the debounce time before we process any other state
			for (i=0; i < 8; ++i) {
				if (ev & (1 << i)) {
					if (sw & (1 << i)) { // Key release
						if (timer_expired(TIMID_SW_LONGPRESS))
							i |= (1 << 7) | (1 << 6);
						else
							i |= (1 << 7);
						sw_event = i;
					} else { // Key push
						sw_event = 0; // To be honest, I don't have a f*cking clue why I need this...
						timer_set(TIMID_SW_LONGPRESS, MS_TO_TICKS(1000));
					}
					timer_set(TIMID_SW_DEBOUNCE, MS_TO_TICKS(250));
					break; // We can only process one event at a time anyway, so let's quit it here
				}
			}
		}
		sw_last = sw;
	}
}

inline uint8_t get_switch_event()
{
	return sw_event;
}

inline void input_clear_events()
{
	rotary_delta = 16;
	sw_event = 0;
}

inline uint8_t get_sbc_state()
{
	return (PORT_SBCMON(PIN) & PIN_SBCMON);
}

// Need to call timer_proc() before calling this function!
void input_proc()
{
	input_proc_rotary();
	input_proc_switches();
}