#include "project.h"

#define GPIO_CLOCK GPIOA
#define GPIO_DATA GPIOB
#define CLOCK 	GPIO5
#define DATA	GPIO11

#define KEYPAD_DELAY do { delay_us(1); } while (0)


#define SCAN_INTERVAL 73
#define DEBOUNCE_INTERVAL 1
#define DEBOUNCE_COUNT 3

static uint32_t next_scan;


uint16_t
keypad_raw_read (void)
{
  uint16_t ret = 0;
  uint16_t c;

/*Reset the state machine in the keypad */

  gpio_set (GPIO_DATA, DATA);
  KEYPAD_DELAY;
  gpio_clear (GPIO_DATA, DATA);
  KEYPAD_DELAY;
  gpio_set (GPIO_DATA, DATA);
  KEYPAD_DELAY;

  gpio_clear (GPIO_CLOCK, CLOCK);
  KEYPAD_DELAY;

  for (c = 0x8000; c; c >>= 1)
    {
      gpio_set (GPIO_CLOCK, CLOCK);
      KEYPAD_DELAY;
      if (!(gpio_get (GPIO_DATA, DATA) & DATA))
        ret |= c;
      gpio_clear (GPIO_CLOCK, CLOCK);
      KEYPAD_DELAY;
    }

  gpio_set (GPIO_CLOCK, CLOCK);

  return ret;
}

uint16_t
keypad_read (void)
{
  int c;
  const uint8_t lut[] = "cdef89ab45670123";
  uint8_t ret = 0;



/*Reset the state machine in the keypad */

  gpio_set (GPIO_DATA, DATA);
  KEYPAD_DELAY;
  gpio_clear (GPIO_DATA, DATA);
  KEYPAD_DELAY;
  gpio_set (GPIO_DATA, DATA);
  KEYPAD_DELAY;

  gpio_clear (GPIO_CLOCK, CLOCK);
  KEYPAD_DELAY;

  for (c = 0; c < 16; ++c)
    {
      gpio_set (GPIO_CLOCK, CLOCK);
      KEYPAD_DELAY;
      if (!(gpio_get (GPIO_DATA, DATA) & DATA))
        ret = lut[c];
      gpio_clear (GPIO_CLOCK, CLOCK);
      KEYPAD_DELAY;
    }

  gpio_set (GPIO_CLOCK, CLOCK);

  return ret;
}


static void
keypad_scan (void)
{
  static uint8_t last_v;
  static uint8_t key_down;
  static int same;
  uint8_t v;

  v = keypad_read ();

  next_scan = DEBOUNCE_INTERVAL;

  if (v!=last_v) {
     last_v=v;
     same=0;
     return;
  } else {
     if (same<DEBOUNCE_COUNT) {
     	same++;
	return;
     }
  }

  if (!v && !key_down)  {	
      next_scan = SCAN_INTERVAL;
      return;
  }

	if (key_down==v) {
		return;
	} else if (key_down!=v) {
	  if (key_down)
          key_event (key_down, 0);
	key_down=v;
	  if (key_down)
          key_event (key_down, 1);
	}
}




void
keypad_tick (void)
{

  if (!next_scan)
    keypad_scan ();
  else
    next_scan--;

}




void
keypad_init (void)
{

  gpio_set_mode (GPIO_CLOCK, GPIO_MODE_OUTPUT_50_MHZ,
                 GPIO_CNF_OUTPUT_OPENDRAIN, CLOCK);
  gpio_set_mode (GPIO_DATA, GPIO_MODE_OUTPUT_50_MHZ,
                 GPIO_CNF_OUTPUT_OPENDRAIN, DATA);



}