/**
 * == Xbox 360 Controller RAPID FIRE Mod ==
 * works with ALL hardware versions of the controller
 * binds the rapidfire function directly to the RT button
 *
 * @author Andi Dittrich <andi.dittrich@a3non.org>
 * @version 1,0
 * @target Attiny 25 - 8Mhz
 * @license MIT Style X11 License
 * @copyright 2011 Andi Dittrich
 *
 * == HARDWARE SETUP ==
 * PB0: Trigger OUT
 * PB2: Trigger IN
 * PB3: LED0
 * PB4: Enable Switch
 *
 * == Controller Trigger Behaviour ==
 * ~ 1.32V released
 * ~ 0.2V pressed 
*/

#include <avr/interrupt.h>
#include <stdio.h>
#include <inttypes.h>
#include <avr/io.h>
#include <avr/wdt.h>
#include <util/delay.h>
#include <stdlib.h>

// trigger state values
#define TRIGGER_RELEASE_OUTPUT_VALUE 254
#define TRIGGER_PRESS_OUTPUT_VALUE 5
#define TRIGGER_SENSITIVITY 450

// switch observer
volatile unsigned char switchState = 2;
volatile unsigned char switchStateChange = 0;

// system state
volatile unsigned char rapidFireOn = 0;

// status led
inline void showStatusLed(unsigned char enabled){
	if (enabled == 1){
		PORTB |= (1<<PB3);
	}else{
		PORTB &= ~(1<<PB3);
	}
};

// get Trigger VADC VALUE
inline unsigned int readADC(){
	// trigger measurement
	ADCSRA |= (1<<ADSC);

	// wait for conversion completed
	while(ADCSRA & (1<<ADSC));

	// return value
	return ADC;
};

// var delay
void randomDelay(){
	unsigned int randomDelayTime = rand();

	// max 32 turns
	randomDelayTime = randomDelayTime >> 11;

	for (unsigned char i=0;i<randomDelayTime;i++){
		_delay_ms(1);
	};
};

// press trigger
inline static void pressTrigger(){
	// simulate slow falling edge
	OCR0A = TRIGGER_PRESS_OUTPUT_VALUE/4;
	_delay_ms(1);

	OCR0A = TRIGGER_PRESS_OUTPUT_VALUE/3;
	_delay_ms(1);

	OCR0A = TRIGGER_PRESS_OUTPUT_VALUE/2;
	_delay_ms(3);

	// press trigger
	OCR0A = TRIGGER_PRESS_OUTPUT_VALUE;
};

// release trigger
inline static void releaseTrigger(){
	OCR0A = TRIGGER_RELEASE_OUTPUT_VALUE/4;
	_delay_ms(1);

	OCR0A = TRIGGER_RELEASE_OUTPUT_VALUE/3;
	_delay_ms(1);

	OCR0A = TRIGGER_RELEASE_OUTPUT_VALUE/2;
	_delay_ms(2);

	// release trigger
	OCR0A = TRIGGER_RELEASE_OUTPUT_VALUE;
};

// fire trigger
inline static void fireTrigger(){
	// press trigger
	pressTrigger();

	// wait 15ms min
	_delay_ms(15);
	
	// random delay max +8ms
	randomDelay();

	// release trigger
	releaseTrigger();

	// wait 6ms min
	_delay_ms(6);

	// random delay max +8ms
	randomDelay();
};

// switch observer ISR - 48ms steady state required
ISR (TIMER1_OVF_vect){
	// SIGNAL A OBERVING
	if (bit_is_clear(PINB, PB4)){
		// increment -> KEY PRESSED
		if (switchState<5){
			switchState++;
		}else{
			// FALLING EDGE DETECTED
			if (switchStateChange==0){
				switchStateChange = 1;
			}
		}
	}else{
		// decrement -> KEY RELEASED
		if (switchState>0){
			switchState--;
		}else{
			// RISING EDGE DETECTED
			if (switchStateChange==1){
				switchStateChange = 2;
			}
		}
	}
};


// MAIN
int main(){
	// == INIT ==

	// Port - LED0, TriggerOut => Out
	DDRB = 0b00001011;

	// Switch Pullup ON
	PORTB = 0b00010000;

	// ADC - TriggerIN ADC1, PB2
	// 7:1 REFS1 - 2.56V Internal Ref
	// 6:0 REFS0 - 2.56V Internal Ref
	// 5:0 ADLAR - ADC Value Right Adjusted
	// 4:1 REFS2 - 2.56V Internal Ref
	// 3:0 MUX3 - ADC1 PB2 IN
	// 2:0 MUX3 - ADC1 PB2 IN
	// 1:0 MUX3 - ADC1 PB2 IN
	// 0:1 MUX3 - ADC1 PB2 IN
	ADMUX = 0b10010001;

	// 7:0 BIN - Unipolar Mode
	// 6:0 ACME - Analog Multiplexer
	// 5:0 IPR - No Input Polarity Reversal
	// 4:0 - RESERVED
	// 3:0 - RESERVED
	// 2:0 ADTS2 Free Running mode
	// 1:0 ADTS1 Free Running mode
	// 0:0 ADTS0 Free Running mode
	ADCSRB = 0b00000000;

	// 7:1 ADEN - Enable ADC
	// 6:1 ADSC - Start ADC
	// 5:0 ADATE - Disbale AutoTrigger
	// 4:0 ADIF - Reset ISR Flag
	// 3:0 ADIE - Disbale ISR
	// 2:1 ADPS2 - Prescaler 64 - 125KHz ADC SamplingRate
	// 1:1 ADPS1 - Prescaler 64 - 125KHz ADC SamplingRate
	// 0:0 ADPS0 - Prescaler 64 - 125KHz ADC SamplingRate
	ADCSRA = 0b11000110;

	GTCCR = 0b0;

	// TIMER 0 - DAC PWM
	// 7:1 COM0A1 - Non Inverting PWM, Clear On Compare Math
	// 6:0 COM0A0 - Non Inverting PWM, Clear On Compare Math
	// 5:0 COM0B1 - Normal Operation
	// 4:0 COM0B0 - Normal Operation
	// 3:0 RESERVED
	// 2:0 RESERVED
	// 1:1 WGM01: Fast PWM
	// 0:1 WGM00: Fast PWM
	TCCR0A = 0b10000011;

	// 7:0 FOC0A
	// 6:0 FOC0B
	// 5:0 RESERVED
	// 4:0 RESERVED
	// 3:0 WGM02 - Fast PWM
	// 2:0 CS02 - No Clock Prescaling
	// 2:0 CS01 - No Clock Prescaling
	// 2:1 CS00 - No Clock Prescaling
	TCCR0B = 0b00000001;

	// TIMER 1 - State Observer
	// 7:0 CTC1 - Continious counting
	// 6:0 PWM1A - Disbale Pulse Modulator A
	// 5:0 COM1A - Comparator disconnected
	// 4:0 COM0A - Comparator disconnected
	// 3:1 CS13 - Prescaler 256 -> 122 Hz Timebase
	// 2:0 CS12 - Prescaler 256 -> 122 Hz Timebase
	// 1:0 CS11 - Prescaler 256 -> 122 Hz Timebase
	// 0:1 CS10 - Prescaler 256 -> 122 Hz Timebase
	TCCR1 = 0b00001001;

	// 7:0 RESERVED
	// 6:0 OCIE1A - Disabled
	// 5:0 OCIE1B - Disabled
	// 4:0 OCIE0A - Disbaled
	// 3:0 OCIE0B - Disabled
	// 2:1 TOIE1 - Timer 1 OVF ISR Enabled
	// 1:0 TOIE0 - Timer 0 OVF ISR Enabled
	// 0:0 RESERVED
	TIMSK = 0b00000100;

	// 7:0 LSM - LowPeedMode
	// 6:0 RESERVED
	// 5:0 RESERVED
	// 4:0 RESERVED
	// 3:0 RESERVED
	// 2:0 PCKE - Synchronous clock mode
	// 1:0 PLLE - PLL Disabled
	// 0:0 PLOCK
	PLLCSR = 0b00000000;

	// watchdog enable
	wdt_enable(WDTO_2S);

	// initialize random
	srand(0b1011100101101001);

	// enable ISR
	sei();

	// ADC Value
	unsigned int TriggerValue = 0;

	// release trigger on default
	OCR0A = TRIGGER_RELEASE_OUTPUT_VALUE;


	// == MAIN LOOP ==
	while (1==1){
		// Read ADC Value
		TriggerValue = readADC();
		
		// RapidFire on ?
		if (rapidFireOn == 1){
			// show led
			showStatusLed(1);

			// send trigger event if trigger pressed => 500 ~ 1.25V
			if (TriggerValue < TRIGGER_SENSITIVITY){
				fireTrigger();
			}else{
				// release trigger
				OCR0A = TRIGGER_RELEASE_OUTPUT_VALUE;
			}
		}else{
			// hide led
			showStatusLed(0);

			// ADC passthrogh -> normalizing values ! max 540 ~ 1.36V

			// normalizing 9bit =>
			TriggerValue = TriggerValue*15/32;

			// limit ranges
			if (TriggerValue > 255){
				TriggerValue = 255;
			}

			// assign output value
			OCR0A = (unsigned char)TriggerValue;
		}

		// switch state change ?
		if (switchStateChange==2){
			// toggle rf mode
			rapidFireOn = rapidFireOn^1;

			// 20ms security delay
			_delay_ms(20);

			// reset flag
			switchStateChange = 0;
		}
		

		// watchdog reset
		wdt_reset();
	}



	return 1;
}