//
// hello.txrx.45.c
//
// step response transmit-receive hello-world
//    9600 baud FTDI interface
//
// Neil Gershenfeld
// 11/6/11
//
// (c) Massachusetts Institute of Technology 2011
// Permission granted for experimental and personal use;
// license for commercial sale available from MIT.
//

//TX RX Include
#include <avr/io.h>
#include <util/delay.h>

//BUS INCLUDE
#include <avr/pgmspace.h>
#include <string.h>

//TX RX DEFINE (I/O)
#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

//BUS DEFINE (I/O)
#define input(directions,pin) (directions &= (~pin)) // set port direction for input

//Test
#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 100 // 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

// Serial For TX RX
#define serial_port PORTB
#define serial_direction DDRB
#define serial_pin_out (1 << PB2) //RX
#define transmit_port PORTB
#define transmit_direction DDRB
#define transmit_pin (1 << PB4) //MOISTURE

//Serial for BUS
//#define serial_port PORTB
//#define serial_direction DDRB
#define serial_pins PINB
#define serial_pin_in (1 << PB0) // also MOSI pin
//#define serial_pin_out (1 << PB4)

//DEFINING NODE
#define node_id '1'

// BUS FUNCTION - GET CHAR
void get_char(volatile unsigned char *pins, unsigned char pin, char *rxbyte) {
   //
   // read character into rxbyte on pins pin
   //    assumes line driver (inverts bits)
   //
   *rxbyte = 0;
   while (pin_test(*pins,pin))
      //
      // wait for start bit
      //
      ;
   //
   // delay to middle of first data bit
   //
   half_bit_delay();
   bit_delay();
   //
   // unrolled loop to read data bits
   //
   if pin_test(*pins,pin)
      *rxbyte |= (1 << 0);
   else
      *rxbyte |= (0 << 0);
   bit_delay();
   if pin_test(*pins,pin)
      *rxbyte |= (1 << 1);
   else
      *rxbyte |= (0 << 1);
   bit_delay();
   if pin_test(*pins,pin)
      *rxbyte |= (1 << 2);
   else
      *rxbyte |= (0 << 2);
   bit_delay();
   if pin_test(*pins,pin)
      *rxbyte |= (1 << 3);
   else
      *rxbyte |= (0 << 3);
   bit_delay();
   if pin_test(*pins,pin)
      *rxbyte |= (1 << 4);
   else
      *rxbyte |= (0 << 4);
   bit_delay();
   if pin_test(*pins,pin)
      *rxbyte |= (1 << 5);
   else
      *rxbyte |= (0 << 5);
   bit_delay();
   if pin_test(*pins,pin)
      *rxbyte |= (1 << 6);
   else
      *rxbyte |= (0 << 6);
   bit_delay();
   if pin_test(*pins,pin)
      *rxbyte |= (1 << 7);
   else
      *rxbyte |= (0 << 7);
   //
   // wait for stop bit
   //
   bit_delay();
   half_bit_delay();
   }

// TX RX & BUS FUNCTION/SENSING - PUT CHAR
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();
   }
   
   //BUS FUNCTION - PUT_STRING
void put_string(volatile unsigned char *port, unsigned char pin, PGM_P str) {
   //
   // send character in txchar on port pin
   //    assumes line driver (inverts bits)
   //
   static char chr;
   static int index;
   index = 0;
   do {
      chr = pgm_read_byte(&(str[index]));
      put_char(&serial_port, serial_pin_out, chr);
      ++index;
      } while (chr != 0);
   }
   
   
int main(void) {
   //
   // main
   // BUS VARIABLES
   static char chr;
   // TXRX VARIABLES
   static unsigned char count;
   static uint16_t up,down;
	
   //Clock Divided is the same for BUS & TXRX
   // set clock divider to /1
   //
   CLKPR = (1 << CLKPCE);
   CLKPR = (0 << CLKPS3) | (0 << CLKPS2) | (0 << CLKPS1) | (0 << CLKPS0);
   //
   // initialize TXRX output pins
   //
   set(serial_port, serial_pin_out);
   output(serial_direction, serial_pin_out);
   clear(transmit_port, transmit_pin);
   output(transmit_direction, transmit_pin);
   
   //
   // initialise BUS output pins
   //set(serial_port, serial_pin_out);
   //input(serial_direction, serial_pin_in);
   //set(led_port, led_pin);
   //output(led_direction, led_pin);
   
   
   //
   // init A/D
   //
   ADMUX = (0 << REFS2) | (0 << REFS1) | (0 << REFS0) // Vcc ref
      | (0 << ADLAR) // right adjust
      | (0 << MUX3) | (0 << MUX2) | (1 << MUX1) | (1 << MUX0); // PB3
   ADCSRA = (1 << ADEN) // enable
      | (1 << ADPS2) | (1 << ADPS1) | (1 << ADPS0); // prescaler /128
   //
   // main loop
   //
   while (1) {
      //get_char(&serial_pins, serial_pin_in, &chr);
      //flash();
      //if (chr == node_id) 
      {
         //output(serial_direction, serial_pin_out);
         //static char message[] PROGMEM = "node ";
         //put_string(&serial_port, serial_pin_out, (PGM_P) message);
         //put_char(&serial_port, serial_pin_out, chr);
         //put_char(&serial_port, serial_pin_out, 10); // new line
         //led_delay();
         //flash();
         //input(serial_direction, serial_pin_out);
         //}
    
      // accumulate
      //
      up = 0;
      down = 0;
      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;
         }
      //
      // 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();
      		}
      	}
      }