#include <avr/io.h>
#include <util/delay.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 102 // 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 settle_delay() _delay_us(100) // settle delay
#define char_delay() _delay_ms(10) // char delay
#define nloop 100 // loops to accumulate

#define serial_port PORTD
#define serial_direction DDRD
#define serial_pin_out (1 << PD5)
#define transmit_port PORTC
#define transmit_direction DDRC
#define transmit_pin (1 << PC3)

#define indicator_direction_1 DDRD
#define indicator_port_1 PORTD
#define indicator_pin_1 (1 << PD1)
#define indicator_pin_2 (1 << PD2)
#define indicator_pin_3 (1 << PD3)
#define indicator_pin_4 (1 << PD4)

volatile uint8_t chanNum = 0;

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();
   }

int main(void) {
   //
   // main
   //
   static unsigned char count;
   static uint16_t up,down, diff, avg;

   unsigned char chr = 87;
   //
   // set clock divider to /1
   //
   CLKPR = (1 << CLKPCE);
   CLKPR = (0 << CLKPS3) | (0 << CLKPS2) | (0 << CLKPS1) | (0 << CLKPS0);
   //
   // initialize output pins
   //
   // set(PORTD, (1<<PD1));
   output(DDRD, (1<<PD1));
   //    set(PORTD, (1<<PD2));
   output(DDRD, (1<<PD2));
   //    set(PORTD, (1<<PD3));
   output(DDRD, (1<<PD3));
   //    set(PORTD, (1<<PD4));
   output(DDRD, (1<<PD4));

   set(serial_port, serial_pin_out);
   output(serial_direction, serial_pin_out);
   
   clear(transmit_port, transmit_pin);
   output(transmit_direction, transmit_pin);


   //
   // init A/D
   //

   ADMUX = (0 << REFS1) | (0 << REFS0) // Aref, but Aref is connected to Vcc, so essentially Vcc
          |(0 << ADLAR)| (0 << MUX3) | (1 << MUX2) | (0 << MUX1) | (1 << MUX0);   //initial ADC5
           // PA2:000010 PA0:000000
   ADCSRA = (1 << ADEN) // enable
      | (1 << ADPS2) | (1 << ADPS1) | (1 << ADPS0); // prescaler /128
   ADCSRB |= (0 << ADLAR); // right adjust
   //
   // main loop
   //


   while (1) {
      clear(indicator_port_1,indicator_pin_1);
      clear(indicator_port_1,indicator_pin_2);
      clear(indicator_port_1,indicator_pin_3);
      clear(indicator_port_1,indicator_pin_4);
      //
      // accumulate
      //

      up = 0;
      down = 0;
      // ADMUX ^= (1<<MUX2);
      for (count = 0; count < nloop; ++count) { 
         //
         // settle, charge
         //
         settle_delay();
         set(transmit_port, transmit_pin);
         //
         // initiate conversion
         //
         ADCSRA |= (1 << ADSC);
         //
         // wait for completion
         //
         while (ADCSRA & (1 << ADSC))
            ;
         //
         // save result
         //
         up += ADC;
         //
         // settle, discharge
         //
         settle_delay();
         clear(transmit_port, transmit_pin);
         //
         // initiate conversion
         //
         ADCSRA |= (1 << ADSC);
         //
         // wait for completion
         //
         while (ADCSRA & (1 << ADSC))
            ;
         //
         // save result
         //
         down += ADC;
         }

         diff = up-down;
         // avg = diff/nloop;

 
         if (diff>25000){
            set(indicator_port_1,indicator_pin_1);
            chr = 70;
            // break;
         }
         else{
            chr = 87;
         }

         

      // put_char(&serial_port, serial_pin_out, 36);
      // char_delay();

      put_char(&serial_port, serial_pin_out, chr);
      char_delay();



      // //send framing
      
      // 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);
      
      // //send result
      
      // put_char(&serial_port, serial_pin_out, (up & 255));
      // char_delay();
      // put_char(&serial_port, serial_pin_out, ((up >> 8) & 255));
      // char_delay();
      // put_char(&serial_port, serial_pin_out, (down & 255));
      // char_delay();
      // put_char(&serial_port, serial_pin_out, ((down >> 8) & 255));
      // char_delay();
      }
   }