// 12-5-15 removed sense6 and sense7 to match 6 pads
// only print pad number (1 to 6)
// Touch Slider
// Frank Vloet
//
// 9600 baud FTDI interface
//

#include <avr/io.h>
#include <util/delay.h>
#include <stdlib.h>
#include <stdio.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 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 charge_delay_1() _delay_us(1) // charge delay 1
#define settle_delay() _delay_us(100) // settle delay
#define char_delay() _delay_ms(10) // char delay

#define serial_port PORTB
#define serial_direction DDRB
#define serial_pin_out (1 << PB1)
#define charge_port PORTB
#define charge_direction DDRB
#define charge_pin (1 << PB2)

#define ref (0 << REFS1) | (0 << REFS0) // reference voltage

#define sense0 (0 << MUX2) | (0 << MUX1) | (0 << MUX0) // PA0
#define sense2 (0 << MUX2) | (0 << MUX1) | (1 << MUX0) // PA1
#define sense4 (0 << MUX2) | (1 << MUX1) | (0 << MUX0) // PA2
#define sense5 (1 << MUX2) | (0 << MUX1) | (1 << MUX0) // PA5
#define sense3 (1 << MUX2) | (1 << MUX1) | (0 << MUX0) // PA6
#define sense1 (1 << MUX2) | (1 << MUX1) | (1 << MUX0) // PA7

#define threshold 600
//Neil's Code to transmit chars
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();
}

//Check an ADCPin identified by bitmask
int check_pin(unsigned char pin) {
	unsigned char up_lo,up_hi,down_lo,down_hi;
	int up_value, down_value, value;
	
	//
	// set the A/D pin
	//
	ADMUX = ref | pin;
	
	//
	// settle, charge, and wait 1
	//
	settle_delay();
	set(charge_port, charge_pin);
	charge_delay_1();
	//
	// initiate conversion
	//
	ADCSRA |= (1 << ADSC);
	//
	// wait for completion
	//
	while (ADCSRA & (1 << ADSC))
		;
	//
	// save result
	//
	up_lo = ADCL;
	up_hi = ADCH;
	//
	// settle, discharge, and wait 1
	//
	settle_delay();
	clear(charge_port, charge_pin);
	charge_delay_1();
	//
	// initiate conversion
	//
	ADCSRA |= (1 << ADSC);
	//
	// wait for completion
	//
	while (ADCSRA & (1 << ADSC))
		;
	//
	// save result
	//
	down_lo = ADCL;
	down_hi = ADCH;
	//
	// process result
	//
	up_value = 256 * up_hi + up_lo;
	down_value = 256 * down_hi + down_lo;
	value = (up_value + (1023 - down_value)) / 2;	
	return threshold - value <= 0 ? 0 : threshold - value;
}

//removedspaces in char str[4] = "    "//
void print_int(int value) {
	char str[4] = "";
  itoa(value, str, 10);
  int i;
  for(i=0; i<4; i++)
  {
    put_char(&serial_port, serial_pin_out, str[i]);
    char_delay();
  }
}

int main(void) {
	//
	// main
	//
	//
	// 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);
	clear(charge_port, charge_pin);
	output(charge_direction, charge_pin);
	//
	// init A/D
	//
	ADMUX = ref; // Vcc ref
	ADCSRA = (1 << ADEN) // enable
		| (1 << ADPS2) | (1 << ADPS1) | (1 << ADPS0); // prescaler /128
	ADCSRB = (0 << ADLAR); // right adjust

  int measurements[7];
  //
	// main loop
	//
	while (1) {
	
   	//
		// sense pins
		//
    measurements[1] = check_pin(sense0); 
    measurements[2] = check_pin(sense1); 
    measurements[3] = check_pin(sense2); 
    measurements[4] = check_pin(sense3); 
    measurements[5] = check_pin(sense4); 
    measurements[6] = check_pin(sense5);
    int i = 0;
    for(i = 0; i<7; i++)
    { 
    if(measurements[i] > 0)
      {
      print_int(i);
//clean      put_char(&serial_port, serial_pin_out, '\r');
//clean      char_delay();
//clean      put_char(&serial_port, serial_pin_out, '\n');
//clean      char_delay();
      }
    }
  }
}