//
//
// hello.light.45.c
//
// phototransistor hello-world
//    9600 baud FTDI interface
//
// Neil Gershenfeld
// 10/27/10
//
// (c) Massachusetts Institute of Technology 2010
// Permission granted for experimental and personal use;
// license for commercial sale available from MIT.
//

#include <avr/io.h>
#include <util/delay.h>
#include <stdlib.h>

#define output(directions,pin) (directions |= pin) // set port direction for output
#define set(port,pin) (port |= pin) // set port pin
#define clear(port,pin) (port &= (~pin)) // clear port pin
#define pin_test(pins,pin) (pins & pin) // test for port pin
#define bit_test(byte,bit) (byte & (1 << bit)) // test for bit set
#define bit_delay_time 8.5 // bit delay for 9600 with overhead
#define bit_delay() _delay_us(bit_delay_time) // RS232 bit delay
#define half_bit_delay() _delay_us(bit_delay_time/2) // RS232 half bit delay
#define char_delay() _delay_ms(10) // char delay
#define position_delay() _delay_ms(1000)

/*
#define serial_port PORTB
#define serial_direction DDRB
#define serial_pin_out (1 << PB2)
*/
#define serial_port PORTA
#define serial_direction DDRA
#define serial_pin_out (1 << PA1)

#define PWM_port PORTA
#define PWM_direction DDRA
#define PWM_IN1_pin (1 << PA6) // IN1
#define PWM_IN2_pin (1 << PA2) // IN2


void put_char(volatile unsigned char *port, unsigned char pin, char txchar) {
   //
   // send character in txchar on port pin
   //    assumes line driver (inverts bits)
   //
   // start bit
   //
   clear(*port,pin);
   bit_delay();
   //
   // unrolled loop to write data bits
   //
   if bit_test(txchar,0)
      set(*port,pin);
   else
      clear(*port,pin);
   bit_delay();
   if bit_test(txchar,1)
      set(*port,pin);
   else
      clear(*port,pin);
   bit_delay();
   if bit_test(txchar,2)
      set(*port,pin);
   else
      clear(*port,pin);
   bit_delay();
   if bit_test(txchar,3)
      set(*port,pin);
   else
      clear(*port,pin);
   bit_delay();
   if bit_test(txchar,4)
      set(*port,pin);
   else
      clear(*port,pin);
   bit_delay();
   if bit_test(txchar,5)
      set(*port,pin);
   else
      clear(*port,pin);
   bit_delay();
   if bit_test(txchar,6)
      set(*port,pin);
   else
      clear(*port,pin);
   bit_delay();
   if bit_test(txchar,7)
      set(*port,pin);
   else
      clear(*port,pin);
   bit_delay();
   //
   // stop bit
   //
   set(*port,pin);
   bit_delay();
   //
   // char delay
   //
   bit_delay();
   }

void put_string(volatile unsigned char *port, unsigned char pin, char *str) {
   //
   // print a null-terminated string
   //
   static int index;
   index = 0;
   do {
      put_char(port, pin, str[index]);
      ++index;
      } while (str[index] != 0);
   }

int main(void) {
   uint8_t low, high;
   uint16_t value;
   uint16_t temp_value;

   //
   // main
   //
   static char chr;  //byte data for serial transmission
   static char chrbig;  //temporary storage of double byte, if that's possible?
   uint8_t theLowADC;
   uint16_t theTenBitResults;
   //
   // set clock divider to /1
   //
   CLKPR = (1 << CLKPCE);
   CLKPR = (0 << CLKPS3) | (0 << CLKPS2) | (0 << CLKPS1) | (0 << CLKPS0);
   //
   // initialize output pins
   //
   set(serial_port, serial_pin_out);
   output(serial_direction, serial_pin_out);
   
   //
   // set up timer 1 for PWM
   //
   TCCR1A = (1 << COM1A1) | (0 << COM1A0); // clear OC1A on compare match
   TCCR1B = (0 << CS12) | (1 << CS11) | (0 << CS10) | (1 << WGM13); // prescaler /8, phase and frequency correct PWM, ICR1 TOP
   ICR1 = 83; // 15000hz frequency
   //
   // set PWM pins to output
   //
   clear(PWM_port, PWM_IN1_pin);
   output(PWM_direction, PWM_IN1_pin);
//   clear(PWM_port, PWM_IN2_pin);
//   output(PWM_direction, PWM__IN2_pin);
   
   //
   // init A/D
   //
   ADMUX =  (0 << REFS1) | (0 << REFS0) // Vcc ref
      | (0 << ADLAR) // right adjust
      | (0 << MUX5) | (0 << MUX4) | (0 << MUX3) | (1 << MUX2) | (1 << MUX1) | (1 << MUX0); // ADC3
   ADCSRA = (1 << ADEN) // enable
      | (1 << ADPS2) | (1 << ADPS1) | (1 << ADPS0); // prescaler /128
   


   //
   // main loop
   //
   while (1) {
      //
      // send framing, essentially check that the datapacket is ready
      //
      /*put_char(&serial_port, serial_pin_out, 1);
      char_delay();
      put_char(&serial_port, serial_pin_out, 2);
      char_delay();
      put_char(&serial_port, serial_pin_out, 3);
      char_delay();
      put_char(&serial_port, serial_pin_out, 4);
      char_delay();
      */
      //
      // initiate conversion
      //
      ADCSRA |= (1 << ADSC);
      //
      // wait for completion of ADC
      //
      while (ADCSRA & (1 << ADSC))
         ;
      //
      // send result
      //
      low = ADCL;
      //put_char(&serial_port, serial_pin_out, chr);
      char_delay();
      high = ADCH;
      //put_char(&serial_port, serial_pin_out, chr);
      char_delay();
      
      temp_value = (high << 8) | low;

      //Adjust PWM delay by pot input
      value = (temp_value * 1);
      //motor PWM frequency set 1ms delay
      //``
      // 1 ms PWM on time
      //
      OCR1A = value;
      //put_char(&serial_port, serial_pin_out, value >> 2);
      //put_char(&serial_port, serial_pin_out, (unsigned char)((theTenBitResults >> 2) & 0xFF) + '0');
      put_char(&serial_port, serial_pin_out, 0x66);
      char buffer[33];
      put_string(&serial_port, serial_pin_out, itoa(temp_value,buffer, 10));
      put_char(&serial_port, serial_pin_out, 0x67);
      //char_delay();
      put_string(&serial_port, serial_pin_out, itoa(value,buffer, 10));
      put_char(&serial_port, serial_pin_out, '\n');
      //char_delay();
      //put_char(&serial_port, serial_pin_out, ADCL);
      
      //position_delay();
      

      }
   }