/*
 * Copyright (C) 2015 Freie Universität Berlin
 *
 * This file is subject to the terms and conditions of the GNU Lesser
 * General Public License v2.1. See the file LICENSE in the top level
 * directory for more details.
 */

/**
 * @ingroup     examples
 * @{
 *
 * @file
 * @brief       Example application for demonstrating the RIOT network stack
 *
 * @author      Hauke Petersen <hauke.petersen@fu-berlin.de>
 *
 * @}
 */

#include <stdio.h>

#include "shell.h"
#include "msg.h"
#include "board.h"
#include "xtimer.h"
#include "periph/gpio.h"

#define ENCODER     GPIO_PIN(PORT_A,8)         
uint32_t rpm; 
uint32_t pulses;  
uint32_t  timeold; 
uint8_t pulsesperturn = 20;

static void gpio_cb(void *pin)
{
  pulses++;
}

int init_encoder(void){
if (gpio_init_int(ENCODER,GPIO_IN, GPIO_RISING, gpio_cb,
                      (void *)ENCODER) < 0) {
        puts("Error while initializing ENCODER pin as external interrupt\n");
        return 1;
    }
    printf("ENCODER GPIO initialized successfuly\n");
 rpm=0; 
 pulses=0;  
 timeold=0;

 return 0;
}

int main(void)
{
    init_encoder();
    for(;;){
     	if (xtimer_now_usec() - timeold >= 1000000){  /*Uptade every one second, this will be equal to reading frecuency (Hz).*/
 
 	 //Don't process interrupts during calculations
   	 gpio_irq_disable(ENCODER);
  	 //Note that this would be 60*1000/(millis() - timeold)*pulses if the interrupt
   	//happened once per revolution
  	 rpm = ((60 * 1000000)/pulsesperturn )/(xtimer_now_usec()-timeold)*pulses;
   	 timeold = xtimer_now_usec();
   	 pulses = 0;
  	 
  	 //Write it out to serial port
   	  printf("speed: %" PRIu32 " rpm\n",rpm);
   	//Restart the interrupt processing
   	 gpio_irq_enable(ENCODER);
   	}
    }  
    return 0;
}