/*
 * buttons.h
 *
 *  Created on: Aug 12, 2012, modified 9/8/2017
 *      Author: Gene Bogdanov
 *
 *  Button debouncer, calibrated for 200 samples/sec.
 */

#ifndef BUTTONS_H_
#define BUTTONS_H_

#include <stdint.h>

#define BUTTON_COUNT 5				// number of buttons excluding joystick directions
#define BUTTON_AND_JOYSTICK_COUNT 9 // number of buttons including joystick directions
#define BUTTON_SAMPLES_PRESSED 2	// number of samples before a button is considered pressed
#define BUTTON_SAMPLES_RELEASED 5	// number of samples before a button is considered released
// counter value indicating button pressed state
#define BUTTON_PRESSED_STATE (BUTTON_SAMPLES_RELEASED*BUTTON_SAMPLES_PRESSED)
#define BUTTON_STATE_INCREMENT (BUTTON_PRESSED_STATE/BUTTON_SAMPLES_PRESSED)
#define BUTTON_STATE_DECREMENT (BUTTON_PRESSED_STATE/BUTTON_SAMPLES_RELEASED)

#define BUTTON_SCAN_RATE 200    // [Hz] button scanning interrupt rate
#define BUTTON_INT_PRIORITY 32  // button interrupt priority (higher number is lower priority)

#define BUTTON_AUTOREPEAT_INITIAL 100   // how many samples must read pressed before autorepeat starts
#define BUTTON_AUTOREPEAT_NEXT 10       // how many samples must read pressed before the next repetition

#define JOYSTICK_UPPER_PRESS_THRESHOLD 2200     // above this ADC value, button is pressed
#define JOYSTICK_UPPER_RELEASE_THRESHOLD 2100   // below this ADC value, button is released
#define JOYSTICK_LOWER_PRESS_THRESHOLD 1700      // below this ADC value, button is pressed
#define JOYSTICK_LOWER_RELEASE_THRESHOLD 1800   // above this ADC value, button is released

#define ADC_SAMPLING_RATE 1000000   // [samples/sec] desired ADC sampling rate
#define CRYSTAL_FREQUENCY 25000000  // [Hz] crystal oscillator frequency used to calculate clock rates

extern volatile uint32_t gButtons;	// debounced button state, one per bit in the lowest bits
extern uint32_t gJoystick[2];       // joystick coordinates
extern uint32_t gADCSamplingRate;   // [Hz] actual ADC sampling rate

// initialize all button and joystick handling hardware
void ButtonInit(void);

// update the debounced button state in the global variable gButtons
// the input argument is a bitmap of raw button state from the hardware
void ButtonDebounce(uint32_t buttons);

// sample joystick and convert to button presses
void ButtonReadJoystick(void);

// autorepeat button presses if a button is held long enough
uint32_t ButtonAutoRepeat(void);

typedef enum {
    SW1 = 0,
    SW2,
    S1,
    S2,
    Select,
    Right,
    Left,
    Up,
    Down,
} Button;

// convert mask into array of buttons
//
// returns length
uint8_t buttons_from_mask(Button *array, uint32_t buttons);

#define FIFO_SIZE 11        // FIFO capacity is 1 item fewer
typedef Button DataType;      // FIFO data type
int fifo_put(DataType data);
int fifo_get(DataType *data);

#endif /* BUTTONS_H_ */