/*
 *  spreadspace avr utils
 *
 *
 *  Copyright (C) 2013-2015 Christian Pointner <equinox@spreadspace.org>
 *
 *  This file is part of spreadspace avr utils.
 *
 *  spreadspace avr utils is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  any later version.
 *
 *  spreadspace avr utils is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with spreadspace avr utils. If not, see <http://www.gnu.org/licenses/>.
 */


#include <avr/io.h>
#include <avr/wdt.h>
#include <avr/interrupt.h>
#include <avr/power.h>
#include <stdio.h>

#include "util.h"
#include "led.h"
#include "usbio.h"

#define PWM_VAL OCR4B
#define PWM_MAX 160

void pwm_init(void)
{
  DDRB |= (1<<PB6);
  TCCR4B = 0; // make sure timer is stopped

  TCCR4A = (1<<COM4B1) | (1<<PWM4B);
  TCCR4D = (1<<WGM40);
  TCNT4 = 0;
  OCR4C = 160;

  OCR4B = 80; // set duty cycle to 50:50
  TCCR4B = (1<<CS41); // start timer
}

inline void pwm_set(uint8_t val)
{
  PWM_VAL = val;
}

inline void pwm_inc(void)
{
  if(PWM_VAL < PWM_MAX)
    PWM_VAL++;
}

inline void pwm_dec(void)
{
  if(PWM_VAL > 0)
    PWM_VAL--;
}


void tacho_init(void)
{
  DDRD &= ~(1<<PD4);
  PORTD |= (1<<PD4);
  TCCR1B = 0; // make sure timer is stopped

  TCCR1A = 0;
  TCNT1 = 0;
  TIMSK1 = (1<<ICIE1);

  TCCR1B = (1<<CS12); // start timer
}

ISR(TIMER1_CAPT_vect)
{
  static uint16_t tacho_last_ts = 0;
  uint16_t current = ICR1;
  uint16_t diff = 0;
  if(current > tacho_last_ts) {
    diff = current - tacho_last_ts;
  } else {
    diff = (UINT16_MAX - tacho_last_ts) + current;
  }
  tacho_last_ts = current;

  float rpm = 1875000.0 / (float)diff ;
  printf("\rtacho: %8.2f rpm", rpm);
}


void handle_cmd(uint8_t cmd)
{
  switch(cmd) {
  case '0': led_off(); printf("ok\r\n"); break;
  case '1': led_on(); printf("ok\r\n"); break;
  case '+': pwm_inc(); printf("pwm = %d\r\n", PWM_VAL);  break;
  case '-': pwm_dec(); printf("pwm = %d\r\n", PWM_VAL); break;
  case 'r': reset2bootloader(); break;
  default: printf("error\r\n"); return;
  }

}

int main(void)
{
  MCUSR &= ~(1 << WDRF);
  wdt_disable();

  cpu_init();
  jtag_disable();

  led_init();
  usbio_init();
  pwm_init();
  tacho_init();
  sei();

      // rotary encoder
  DDRB &= ~((1<<PB4) | (1<<PB5));
  PORTB |= (1<<PB4) | (1<<PB5);

  led_on();
  for(;;) {
    int16_t BytesReceived = usbio_bytes_received();
    while(BytesReceived > 0) {
      int ReceivedByte = fgetc(stdin);
      if(ReceivedByte != EOF) {
        handle_cmd(ReceivedByte);
      }
      BytesReceived--;
    }

    usbio_task();
  }
}