/*
  spindle_control.c - spindle control methods
  Part of Grbl v0.9

  Copyright (c) 2012-2014 Sungeun K. Jeon

  Grbl 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
  (at your option) any later version.

  Grbl 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 Grbl.  If not, see <http://www.gnu.org/licenses/>.
*/
/* 
  This file is based on work from Grbl v0.8, distributed under the 
  terms of the MIT-license. See COPYING for more details.  
    Copyright (c) 2009-2011 Simen Svale Skogsrud
    Copyright (c) 2012 Sungeun K. Jeon
*/ 
/* RC-Servo PWM modification: switch between 1ms and 2ms pulse-width at 61Hz
   Prescaler 1024 = 15625Hz / 256Steps =  61Hz	64µs/step -> Values 15 / 32 for 1ms / 2ms
   Reload value = 0x07
   Replace this file in C:\Program Files (x86)\Arduino\libraries\GRBL
*/
#define RC_SERVO_SHORT     15
#define RC_SERVO_LONG      32
#define RC_SERVO_INVERT     1

#include "system.h"
#include "spindle_control.h"
#include "protocol.h"
#include "gcode.h"


void spindle_init()
{    
  SPINDLE_PWM_DDR |= (1<<SPINDLE_PWM_BIT); // Configure as PWM output pin.
  SPINDLE_DIRECTION_DDR |= (1<<SPINDLE_DIRECTION_BIT); // Configure as output pin.
  spindle_stop();
}


void spindle_stop()
{     
      #ifdef RC_SERVO_INVERT 
          OCR_REGISTER = RC_SERVO_LONG;
      #else
          OCR_REGISTER = RC_SERVO_SHORT;
      #endif    
}


void spindle_run(uint8_t direction, float rpm) 
{
  if (sys.state == STATE_CHECK_MODE) { return; }
  
  // Empty planner buffer to ensure spindle is set when programmed.
  protocol_auto_cycle_start();  //temp fix for M3 lockup
  protocol_buffer_synchronize(); 
  
  if (direction == SPINDLE_DISABLE) {

    spindle_stop();

  } else {
    if (direction == SPINDLE_ENABLE_CW) {
      SPINDLE_DIRECTION_PORT &= ~(1<<SPINDLE_DIRECTION_BIT);
    } else {
      SPINDLE_DIRECTION_PORT |= (1<<SPINDLE_DIRECTION_BIT);
    }

      // TODO: Install the optional capability for frequency-based output for servos.
      #define SPINDLE_RPM_RANGE (SPINDLE_MAX_RPM-SPINDLE_MIN_RPM)
      #define RC_SERVO_RANGE (RC_SERVO_LONG-RC_SERVO_SHORT)
      TCCRA_REGISTER = (1<<COMB_BIT) | (1<<WAVE1_REGISTER) | (1<<WAVE0_REGISTER);
      TCCRB_REGISTER = (TCCRB_REGISTER & 0b11111000) | 0x07; // set to 1/1024 Prescaler
      rpm -= SPINDLE_MIN_RPM;
      if ( rpm > SPINDLE_RPM_RANGE ) { rpm = SPINDLE_RPM_RANGE; } // Prevent uint8 overflow

      #ifdef RC_SERVO_INVERT 
          uint8_t current_pwm = floor( RC_SERVO_LONG - rpm*(RC_SERVO_RANGE/SPINDLE_RPM_RANGE));
          OCR_REGISTER = current_pwm;
      #else
          uint8_t current_pwm = floor( rpm*(RC_SERVO_RANGE/SPINDLE_RPM_RANGE) + RC_SERVO_SHORT);
          OCR_REGISTER = current_pwm;
      #endif    
  }
}