/*

  ================================================================================

	This program measures the amount of light that is detected by both the bottom-side
	track sensor diodes. These measured values are used to control the brightness of
	the corresponding brake leds.
	The left  brake led will shine brigther if the left  track-sensor receives more light.
	The right brake led will shine dimmer   if the right track-sensor receives more light.

	Timer/counter0 is running free, counting up from 0 to 255 and then restarts counting
	from 0. Each time timer/counter0 counts from 255 to 0, an interrupt will be generated.
	This will happen each 250us or with a frequency of 3906Hz.
	
	The timer/counter0 interrupt-handler function will start the AD-Converter to read one
	of both track sensors. As an AD-Conversion takes some time, the conversion is only
	started and if completed will generate an AD-Conversion-finished interrupt.
	The timer/counter0 interrupt function automatically toggles starting reading left or 
	right track sensor.
	
	The AD-Conversion-finished interrupt-handler stores the measured value from left
	or right track-sensor in different track-sensor-variables.
	
	Timer1 is continuously counting up and then counting douwn. Each time when value 0
	is reached an interrupt will occur. This interrupt function will copy the 
	track-sensor-variables into compare value A and compare value B.
	
	When counter1 reached compare value A while upcounting or while downcounting an
	compareA interrupt will occur. Same story applies to B generating a compareB interrupt.
	Inside both interrupt handlers the corresponding brake-leds are toggled on or off.
	
  Using: 
   - timer/counter0 with overflow interrupt
   - AD-Conversion with interrupt (interrupt toggles between reading left/right sensor)
   - timer/counter1 with zero/compareA/compareB interrupts
	 
  ================================================================================

	Program				: Asuro 017, Build 001, Left/right tracksensor controls left/right breakled.c
	Release date	: 2005-02-11
	Author				: Henk van Winkoop

	Build	: 001, 2005-02-11, original release

  ================================================================================

*/

//--------------------------------------------------------------------------------
//	INCLUDES
//--------------------------------------------------------------------------------
	#include "hvwdefines.h"
//--------------------------------------------------------------------------------
//	GLOBAL VARIABLES
//--------------------------------------------------------------------------------
	volatile byte gyCurLftTrkSnsVal;
	volatile byte gyCurRgtTrkSnsVal;
//================================================================================
//  TOGGLE LEFT BRAKE LED
//================================================================================
void vToggleLeftBrakeLed(void){
	//---toggle-tracking-led---//
	//if tracking led is on
	if(PORTC&BOD_LFT_H){
		//switch tracking led off
		SFRX(PORTC,BOD_LFT_L);
	}
	//if tracking led is off
	else{
		//switch tracking led on
		SFRX(PORTC,BOD_LFT_H);
	}
}
//================================================================================
//  TOGGLE RIGHT BRAKE LED
//================================================================================
void vToggleRightBrakeLed(void){
	//---toggle-tracking-led---//
	//if tracking led is on
	if(PORTC&BOD_RGT_H){
		//switch tracking led off
		SFRX(PORTC,BOD_RGT_L);
	}
	//if tracking led is off
	else{
		//switch tracking led on
		SFRX(PORTC,BOD_RGT_H);
	}
}
//================================================================================
//  INIT UNUSED IO PORTS
//================================================================================
void vInitUnusedIoPorts(void){

  //disconnect both left engine connections from VCC

  //+-------------------------------------------------------------------------------------------+
  //| Init microcontroller I/O-port D                                                           |
  //+-------------------------------------------------------------------------------------------+
  //|                                                                                           |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|port name  |   PD7   |   PD6   |   PD5   |   PD4   |   PD3   |   PD2   |   PD1   |   PD0   |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|bit number |    7    |    6    |    5    |    4    |    3    |     2   |     1   |    0    |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|pin number |   13    |   12    |   11    |    6    |    5    |     4   |     3   |    2    |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|signal name|BOD_COM  |TRK_LED  |REV_LFT  |FWD_LFT  |SWI_IAC  |SLD_RED  |IR_TXD2  |IR_RXD   |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  SFRX ( DDRD   ,                    REV_LFT_O|FWD_LFT_O                                        ); 
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  SFRX ( PORTD  ,                    REV_LFT_H|FWD_LFT_H                                        ); 
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+

  //disconnect both right engine connections from VCC

  //+-------------------------------------------------------------------------------------------+
  //| DDRB =  Data Direction Register port B                                                    |
  //+-------------------------------------------------------------------------------------------+
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|port name  |   PB7   |   PB6   |   PB5   |   PB4   |   PB3   |   PB2   |   PB1   |   PB0   |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|bit number |    7    |    6    |    5    |    4    |    3    |     2   |     1   |    0    |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|pin number |   10    |    9    |   19    |   18    |   17    |    16   |    15   |   14    |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|signal name|  XTAL2  |  XTAL1  |REV_RGT  |FWD_RGT  |IR_TXD1  |SPD_RGT  |SPD_LFT  |SLD_GRN  |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  SFRX ( DDRB   ,                    REV_RGT_O|FWD_RGT_O                                        );
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  SFRX ( PORTB  ,                    REV_RGT_H|FWD_RGT_H                                        );
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+

  //set left/right engine speed ports as output and low (low = engines disabled)

  //+-------------------------------------------------------------------------------------------+
  //| DDRB =  Data Direction Register port B                                                    |
  //+-------------------------------------------------------------------------------------------+
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|port name  |   PB7   |   PB6   |   PB5   |   PB4   |   PB3   |   PB2   |   PB1   |   PB0   |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|bit number |    7    |    6    |    5    |    4    |    3    |     2   |     1   |    0    |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|pin number |   10    |    9    |   19    |   18    |   17    |    16   |    15   |   14    |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|signal name|  XTAL2  |  XTAL1  |REV_RGT  |FWD_RGT  |IR_TXD1  |SPD_RGT  |SPD_LFT  |SLD_GRN  |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  SFRX ( DDRB   ,                                                  SPD_RGT_O|SPD_LFT_O          );
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  SFRX ( PORTB  ,                                                  SPD_RGT_L|SPD_LFT_L          );
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
}
//================================================================================
//  INIT TIMER COUNTER 1 MODE 10
//================================================================================
void vInitTimerCounter1Mode10(void){

  //---init-timer-counter-register-1-for-controlling-engine-speeds---//

  //CLK-i/o lijkt 8MHz/2=4MHz te zijn!
  //In Waveform Generation Mode 1, 8-bit, TOP = 0xFF = 255
  //In prescaler mode 1, Counter clock (CLK-i/o) should be external clock	(8MHz) but seems to be external clock / 2 (4MHz)
  //Frequency = CLK-i/o / 8 / 256 = 4MHz / 8 / 256 = 2KHz

  //+-------------------------------------------------------------------------------------------+
  //| TCCR1B = Timer Counter 1 Control Register B                                               |
  //+-------------------------------------------------------------------------------------------+
  //|                                                                                           |
  //| CSnn = Clock Source                                                                       |
  //| 000 = no clock source, timer/counter stopped                  (counter max set to 0x00FF) |
  //| 001 = 8MHz/   1 = 8.000.000Hz => /256 = 31250.00Hz =     32us                             |
  //| 010 = 8MHz/   8 = 1.000.000Hz => /256 =  3906.25Hz =    256us                             |
  //| 011 = 8MHz/  64 =   125.000Hz => /256 =   488.28Hz =   2048us                             |
  //| 100 = 8MHz/ 256 =    31.250Hz => /256 =   122.07Hz =  8.192us                             |
  //| 101 = 8MHz/1024 =     7.813Hz => /256 =    30.52Hz = 32.768us                             |
  //| 110 = External clock source on T0 pin. Clock on falling edge                              |
  //| 111 = External clock source on T0 pin. Clock on rising edge                               |
  //|                                                                                           |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|bit number |    7    |    6    |    5    |    4    |    3    |     2   |     1   |    0    |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|signal name| ICNC1_X | ICES1_X |RESERVED | WGM13_X | WGM12_X | CS12_X  | CS11_X  | CS10_X  |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  SFRX ( TCCR1B ,
                  ICNC1_L                                                                       |  //no noise-canceler (no 4 clock AD conversion delay)
                            ICES1_L                                                             |  //no 'input capture' selection
                                     RESERVED                                                   |  //unused
                                                WGM13_H | WGM12_L                               |  //high part of timer1 operating mode 10 selection
                                                                    CS12_L  | CS11_H  | CS10_L  ); //timer1 runs at 3906Hz (see list above)
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+



  //+-------------------------------------------------------------------------------------------+
  //| TCCR1A = Timer Counter 1 Control Register A                                               |
  //+-------------------------------------------------------------------------------------------+
  //|                                                                                           |
  //|                                                                                           |
  //|                                                                                           |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|bit number |    7    |    6    |    5    |    4    |    3    |     2   |     1   |    0    |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|signal name|COM1A1_X |COM1A0_X |COM1B1_X |COM1B0_X | FOC1A_X | FOC1B_X | WGM11_X | WGM10_X |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  SFRX ( TCCR1A ,
                 COM1A1_L |COM1A0_L                                                             |  //deselect 'timer1 controlling pin OC1A (left  engine speed) directly'
                                     COM1B1_L |COM1B0_L                                         |  //deselect 'timer1 controlling pin OC1B (right engine speed) directly'
                                                          FOC1A_L | FOC1B_L                     |  //set to 0 in PWM mode (for compatibility, see pdf page 96)
                                                                              WGM11_H | WGM10_L ); //low part of timer1 operating mode 10 selection
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
	
	
  //+-------------------------------------------------------------------------------------------+
  //| TIMSK = Timer/Counter Interrupt Mask Register                                             |
  //+-------------------------------------------------------------------------------------------+
  //|                                                                                           |
  //| OCIE2    = timer/counter2, output-compare-match interrupt enable                          |
  //| TOIE2    = timer/counter2, overflow interrupt enable                                      |
  //| TICIE1   = timer/counter1, input-capture interrupt enable                                 |
  //| OCIE1A   = timer/counter1, equal to output-compare-A-match register, interrupt enable     |
  //| OCIE1B   = timer/counter1, equal to output-compare-B-match register, interrupt enable     |
  //| TOIE1    = timer/counter1 overflow interrupt enable                                       |
  //| RESERVED = unused                                                                         |
  //| TOIE0    = timer/counter0 overflow interrupt enable                                       |
  //|                                                                                           |
  //+-------------------------------------------------------------------------------------------+
  //| enable timer/counter1 interrupt on output compares A and B                                |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|           | Timer2  | Timer2  | Timer1  | Timer1  | Timer1  | Timer1  |    -    | Timer0  |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|bit number |    7    |    6    |    5    |    4    |    3    |     2   |     1   |    0    |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|signal name| OCIE2_X | TOIE2_X |TICIE1_X |OCIE1A_X |OCIE1B_X | TOIE1_X |RESERVED | TOIE0_X |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  SFRX ( TIMSK  ,
                  OCIE2_L | TOIE2_L |TICIE1_L                               |RESERVED | TOIE0_L |  //not used
                                               OCIE1A_H |OCIE1B_H                               |  //A + B compare interrupts enable
                                                                    TOIE1_H                     ); //timer1 overflow interrupt enable
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+


}
//================================================================================//
//  ENABLE GLOBAL INTERRUPT                                                       //
//================================================================================//
void vEnableGlobalInterrupt(void){
  //+-------------------------------------------------------------------------------------------+
  //| SREG =  Status Register                                                                   |
  //+-------------------------------------------------------------------------------------------+
  //|                                                                                           |
  //| GIE  = I = Global Interrupt Enable                                                        |
  //| BCS  = T = Bit Copy Storage                                                               |
  //| HCF  = H = Half Carry Flag                                                                |
  //| SB   = S = Sign Bit                                                                       |
  //| TCOF = V = Two's Complement Overflow Flag                                                 |
  //| GIE  = I = Global Interrupt Enable                                                        |
  //| NF   = N = Negative Flag                                                                  |
  //| ZF   = Z = Zero Flag                                                                      |
  //| CF   = C = Carry Flag                                                                     |
  //|                                                                                           |
  //+-------------------------------------------------------------------------------------------+
  //| programmer settings comment                                                               |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|bit number |    7    |    6    |    5    |    4    |    3    |     2   |     1   |    0    |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //| SREG      |  GIE_X  |  BCS_X  |  HCF_X  |  SB_X   | TCOF_X  |  NF_X   |  ZF_X   |  CF_X   |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  SFRX ( SREG   ,  GIE_H                                                                        );
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //                 n         .         .         .         .         .         .         .    = 1 = global interrupt enable
  //                 .         n         .         .         .         .         .         .    = 1 =
  //                 .         .         n         .         .         .         .         .    = 1 =
  //                 .         .         .         n         .         .         .         .    = 1 =
  //                 .         .         .         .         n         .         .         .    = 1 =
  //                 .         .         .         .         .         n         .         .    = 1 = 
  //                 .         .         .         .         .         .         n         .    = 1 = 
  //                 .         .         .         .         .         .         .         n    = 1 =
  //+-------------------------------------------------------------------------------------------+
}
/*
//================================================================================//
//  SELECT LEFT TRACK SENSOR AS AD-CONVERTER INPUT                                //
//================================================================================//
void vSelectLeftTrackSensorAsAdcInput(void){
  //+-------------------------------------------------------------------------------------------+
  //| ADMUX = ADC Multiplexer Selection Register                                                |
  //+-------------------------------------------------------------------------------------------+
  //|                                                                                           |
  //| REFSn = select reference voltage source (= maximum measurement voltage value)             |
  //| ADLAR = left justify or right justify measured value into register ADCH/ADCL              |
  //| MUXn  = select measurement-point to be connected to the AD-converter measurement input    |
  //|                                                                                           |
  //+-------------------------------------------------------------------------------------------+
  //| select AVCC pin as reference, use left justify, use left track sensor as measurement-point|
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|bit number |    7    |    6    |    5    |    4    |    3    |     2   |     1   |    0    |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //| ADMUX     | REFS1_X | REFS0_X | ADLAR_X |RESERVED | MUX3_X  | MUX2_X  | MUX1_X  | MUX0_X  |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  SFRX ( ADMUX  , REFS1_L | REFS0_H | ADLAR_H |RESERVED | MUX3_L  | MUX2_L  | MUX1_H  | MUX0_H  );
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //                 n         n         .         .         .         .         .         .    = 00 = external AREF pin
  //                 n         n         .         .         .         .         .         .    = 01 = external AVCC pin with capacitor at AREF pin
  //                 n         n         .         .         .         .         .         .    = 10 = reserved
  //                 n         n         .         .         .         .         .         .    = 11 = internal 2.56V Voltage Reference with external capacitor at AREF pin
  //                 .         .         n         .         .         .         .         .    = 0 = right justify => ADCH:ADCL = ......98:76543210
  //                 .         .         n         .         .         .         .         .    = 1 = left  justify => ADCH:ADCL = 98765432:10......
  //                 .         .         .         .         n         n         n         n    =  select AD-Converter measurement input
  //                                                         n         n         n         n    = 0000-0111 = external pins ADC0 - ADC7
  //                                                         n         n         n         n    = 1000-1101 = reserved
  //                                                         n         n         n         n    = 1110      = internal bandgap level 1.23V
  //                                                         n         n         n         n    = 1111      = external AGND pin level
  //+-------------------------------------------------------------------------------------------+
}
*/
//================================================================================
//  INIT AD-CONVERTER USING INTERRUPT
//================================================================================
void vInitAdConverterUsingInterrupt(void){
  //+-------------------------------------------------------------------------------------------+
  //| ADMUX = ADC Multiplexer Selection Register                                                |
  //+-------------------------------------------------------------------------------------------+
  //|                                                                                           |
  //| REFSn = select reference voltage source (= maximum measurement voltage value)             |
  //| ADLAR = left justify or right justify measured value into register ADCH/ADCL              |
  //| MUXn  = select measurement-point to be connected to the AD-converter measurement input    |
  //|                                                                                           |
  //+-------------------------------------------------------------------------------------------+
  //| select AVCC pin as reference, use left justify, use left track sensor as measurement-point|
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|bit number |    7    |    6    |    5    |    4    |    3    |     2   |     1   |    0    |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //| ADMUX     | REFS1_X | REFS0_X | ADLAR_X |RESERVED | MUX3_X  | MUX2_X  | MUX1_X  | MUX0_X  |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  SFRX ( ADMUX  , REFS1_L | REFS0_H | ADLAR_H |RESERVED | MUX3_L  | MUX2_L  | MUX1_L  | MUX0_L  );
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //                 n         n         .         .         .         .         .         .    = 00 = external AREF pin
  //                 n         n         .         .         .         .         .         .    = 01 = external AVCC pin with capacitor at AREF pin
  //                 n         n         .         .         .         .         .         .    = 10 = reserved
  //                 n         n         .         .         .         .         .         .    = 11 = internal 2.56V Voltage Reference with external capacitor at AREF pin
  //                 .         .         n         .         .         .         .         .    = 0 = right justify => ADCH:ADCL = ......98:76543210
  //                 .         .         n         .         .         .         .         .    = 1 = left  justify => ADCH:ADCL = 98765432:10......
  //                 .         .         .         .         n         n         n         n    =  select AD-Converter measurement input
  //                                                         n         n         n         n    = 0000-0111 = external pins ADC0 - ADC7
  //                                                         n         n         n         n    = 1000-1101 = reserved
  //                                                         n         n         n         n    = 1110      = internal bandgap level 1.23V
  //                                                         n         n         n         n    = 1111      = external AGND pin level
  //+-------------------------------------------------------------------------------------------+
	
  //+-------------------------------------------------------------------------------------------+
  //| ADCSRA = ADC Control and Status Register A                                                |
  //+-------------------------------------------------------------------------------------------+
  //|                                                                                           |
  //| A complete ad-conversion takes 13 clock cycles (clock speed defined by prescaler)         |
  //|                                                                                           |
  //| ADEN = enable ad-converter (switch ad-converter on, consumes extra current)               |
  //| ADSC = start ad-conversion (set low by microcontroller if conversion has finished)        |
  //| ADFR = select free-running mode (checking on ADSC or ADIF bit is useless)                 |
  //| ADIF = ad-converter interrupt flag (is set when conversion has finished, using interrupt) |
  //| ADIE = ad-converter interrupt enable (interrupt occurs when conversion has finished)      |
  //| ADPSn = select ad-converter clock prescaler                                               |
  //|                                                                                           |
  //+-------------------------------------------------------------------------------------------+
  //| ADC Clock frequency should be between 50KHz and 200KHz (.pdf)                             |
  //|                                                                                           |
  //| Prescaler     ADC clock freq.           measured ADC duration (by oscilloscoop)           |
  //|                                                                                           |
  //| 000           8 MHz/  2 = 4000 KHz        7.8 us                                          |
  //| 001           8 MHz/  2 = 4000 KHz        7.8 us                                          |
  //| 010           8 MHz/  4 = 2000 KHz       10   us                                          |
  //| 011           8 MHz/  8 = 1000 KHz       16   us                                          |
  //| 100           8 MHz/ 16 =  500 KHz       30   us                                          |
  //| 101           8 MHz/ 32 =  250 KHz       55   us                                          |
  //| 110           8 MHz/ 64 =  125 KHz      110   us   <--- use these                         |
  //| 111           8 MHz/128 =   63 KHz      230   us                                          |
  //|                                                                                           |
  //+-------------------------------------------------------------------------------------------+
  //| enable ADC, nostart ADC, no free-running, interrupt enabled, clear int. flag, prescaler 6 |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|bit number |    7    |    6    |    5    |    4    |    3    |     2   |     1   |    0    |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //| ADCSRA    | ADEN_X  | ADSC_X  | ADFR_X  | ADIF_X  | ADIE_X  | ADPS2_X | ADPS1_X | ADPS0_X |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  SFRX ( ADCSRA , ADEN_H  | ADSC_L  | ADFR_L  | ADIF_L  | ADIE_H  | ADPS2_H | ADPS1_H | ADPS0_L );
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //                 n         .         .         .         .         .         .         .    = 1 = AD-Converter enable
  //                 .         n         .         .         .         .         .         .    = 1 = start AD-conversion
  //                 .         n         .         .         .         .         .         .    = 0 = AD-conversion finished
  //                 .         .         n         .         .         .         .         .    = 1 = free running mode
  //                 .         .         .         n         .         .         .         .    = 1 = interrupt (or: conversion finished)
  //                 .         .         .         .         n         .         .         .    = 1 = AD-conversion interrupt enable
  //                 .         .         .         .         .         n         n         n    = ADC prescaler
  //                 .         .         .         .         .         n         n         n    = 000-111 = adc clock division factors
  //                 .         .         .         .         .         n         n         n    = 0=2,1=2,2=4,3=8,4=16,5=32,6=64,7=128
  //+-------------------------------------------------------------------------------------------+
}
//================================================================================
//  INIT TIMER 0
//================================================================================
void vSetupFreeRunningTimer0UsingOverflowInterrupt(void){

  //+-------------------------------------------------------------------------------------------+
  //| TCCR0 = Timer/Counter Control Register                                                    |
  //+-------------------------------------------------------------------------------------------+
  //|                                                                                           |
  //| CSnn = Clock Source                                                                       |
  //|                                                                                           |
  //+-------------------------------------------------------------------------------------------+
  //| use clkio/1024 that makes freerunning frequency of 30.52Hz                                |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|bit number |    7    |    6    |    5    |    4    |    3    |     2   |     1   |    0    |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|           |    -    |    -    |    -    |    -    |    -    | Timer0  | Timer0  | Timer0  |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //| TCCR0     |RESERVED |RESERVED |RESERVED |RESERVED |RESERVED | CS02_X  | CS01_X  | CS00_X  |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  SFRX ( TCCR0  ,RESERVED |RESERVED |RESERVED |RESERVED |RESERVED | CS02_H  | CS01_L  | CS00_H  );
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  // 0MHz                                                              n         n         n    = 000 = No clock source (Timer/Counter stopped).
  // 8MHz/   1 = 8.000.000Hz => /256 = 31250.00Hz =     32us           n         n         n    = 001 = clkI/O/(No prescaling)
  // 8MHz/   8 = 1.000.000Hz => /256 =  3906.25Hz =    256us           n         n         n    = 010 = clkI/O/8 (From prescaler)
  // 8MHz/  64 =   125.000Hz => /256 =   488.28Hz =   2048us           n         n         n    = 011 = clkI/O/64 (From prescaler)
  // 8MHz/ 256 =    31.250Hz => /256 =   122.07Hz =  8.192us           n         n         n    = 100 = clkI/O/256 (From prescaler)
  // 8MHz/1024 =     7.813Hz => /256 =    30.52Hz = 32.768us           n         n         n    = 101 = clkI/O/1024 (From prescaler)
  //                                                                   n         n         n    = 110 = External clock source on T0 pin. Clock on falling edge.
  //                                                                   n         n         n    = 111 = External clock source on T0 pin. Clock on rising edge.
  //+-------------------------------------------------------------------------------------------+

	
  //+-------------------------------------------------------------------------------------------+
  //| TIMSK = Timer/Counter Interrupt Mask Register                                             |
  //+-------------------------------------------------------------------------------------------+
  //|                                                                                           |
  //| OCIE2    = timer/counter2, output-compare-match interrupt enable                          |
  //| TOIE2    = timer/counter2, overflow interrupt enable                                      |
  //| TICIE1   = timer/counter1, input-capture interrupt enable                                 |
  //| OCIE1A   = timer/counter1, equal to output-compare-A-match register, interrupt enable     |
  //| OCIE1B   = timer/counter1, equal to output-compare-B-match register, interrupt enable     |
  //| TOIE1    = timer/counter1 overflow interrupt enable                                       |
  //| RESERVED = unused                                                                         |
  //| TOIE0    = timer/counter0 overflow interrupt enable                                       |
  //|                                                                                           |
  //+-------------------------------------------------------------------------------------------+
  //| enable timer/counter0 interrupt                                                           |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|           | Timer2  | Timer2  | Timer1  | Timer1  | Timer1  | Timer1  |    -    | Timer0  |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|bit number |    7    |    6    |    5    |    4    |    3    |     2   |     1   |    0    |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|signal name| OCIE2_X | TOIE2_X |TICIE1_X |OCIE1A_X |OCIE1B_X | TOIE1_X |RESERVED | TOIE0_X |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  SFRX ( TIMSK  ,                                                                       TOIE0_H ); //Timer0 overflow (0xFF->0x00) interrupt enable
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
	
	
	
  //+-------------------------------------------------------------------------------------------+
  //| TCNT0 = Timer/Counter0 Register                                                           |
  //+-------------------------------------------------------------------------------------------+
  //|                                                                                           |
  //|                                                                                           |
  //|                                                                                           |
  //+-------------------------------------------------------------------------------------------+
  //| timer/counter 0 read/write counter value                                                  |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|bit number |    7    |    6    |    5    |    4    |    3    |     2   |     1   |    0    |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //|           | Timer0  | Timer0  | Timer0  | Timer0  | Timer0  | Timer0  | Timer0  | Timer0  |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  //| TCT0      |  bit7   |  bit6   |  bit5   |  bit4   |  bit3   |  bit2   |  bit1   |  bit0   |
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
  SFRW ( TCNT0  , 0x00                                                                          ); //clear timer/counter0
  //+-----------+---------+---------+---------+---------+---------+---------+---------+---------+
}
//================================================================================
//	MAIN
//================================================================================
int main(void){

	//stop the 36KHz timer2 (left active by boot sector) but does not harm anything
	SFRX(TCCR2,CS22_L|CS21_L|CS20_L);

	//---init-green-system-led---//
	//set green system led UC-pin as low (led off)
	SFRX(PORTB,SLD_GRN_L);
	//set green system led UC-pin as output
	SFRX(DDRB ,SLD_GRN_O);

	//---init-red-system-led---//
	//set red system led UC-pin as low (led off)
	SFRX(PORTD,SLD_RED_L);
	//set red system led UC-pin as output
	SFRX(DDRD ,SLD_RED_O); 

	//---init-track-led---//
	//set tracking led UC-pin as low (led off)
	SFRX(PORTD,TRK_LED_L);
	//set tracking led UC-pin as output
	SFRX(DDRD, TRK_LED_O);
	
	//---init-break-leds---//
	//set brake leds common kathode UC-pin to low
	SFRX(PORTD,BOD_COM_L);
	//set brake leds common kathode UC-pin to output
	SFRX(DDRD ,BOD_COM_O);
	//set both brake leds anode UC-pins to low (leds off)
	SFRX(PORTC,BOD_LFT_L|BOD_RGT_L);
	//set both brake leds anode UC-pins to outpouts
	SFRX(DDRC ,BOD_LFT_O|BOD_RGT_O);

	//init unused io-ports
	vInitUnusedIoPorts();
	
	//init timer/counter1 to generate two different interrupts depending on two compare-values
	vInitTimerCounter1Mode10();

	//define timer/counter1 max count value (write high byte first!)
	ICR1H=0x00;
	ICR1L=0xFF;

	//enable global interrupt
	vEnableGlobalInterrupt();

	//init ad-converter using interrupt
	vInitAdConverterUsingInterrupt();

	//select left tracking sensor as ad-converter measurement-input
	SFRX(ADMUX,MUX3_L|MUX2_L|MUX1_H|MUX0_H);

	//start timer/counter0
	vSetupFreeRunningTimer0UsingOverflowInterrupt();

	//endless loop
	while(1);

	//exit function
	return 0;
	
}
//================================================================================
// interrupt handler for timer/counter0 overflow
// #define SIG_OVERFLOW0 _VECTOR(9)
// Enable bit: Register TIMSK, Bit TOIE0 (bit0)
//================================================================================
SIGNAL (SIG_OVERFLOW0){
	//start ad-conversion
	SFRX(ADCSRA,ADSC_H);
}
//================================================================================
// interrupt handler, timer/counter1 output compare A
// enable bit: register TIMSK bit OCIE1A
// #define SIG_OUTPUT_COMPARE1A	_VECTOR(6)
//================================================================================
SIGNAL(SIG_OUTPUT_COMPARE1A){
	//toggle left brake led
	vToggleLeftBrakeLed();
}
//================================================================================
// interrupt handler, timer/counter1 output compare B
// enable bit: register TIMSK bit OCIE1B
// #define SIG_OUTPUT_COMPARE1B _VECTOR(7)
//================================================================================
SIGNAL(SIG_OUTPUT_COMPARE1B){
	//toggle right brake led
	vToggleRightBrakeLed();
}
//================================================================================
// interrupt handler, timer/counter1 overflow
// enable bit: register TIMSK bit TOIE1
// #define SIG_OVERFLOW1 _VECTOR(8)
//================================================================================
SIGNAL(SIG_OVERFLOW1){
	//copy measured left track-sensor value into compare A register
	OCR1A=gyCurLftTrkSnsVal^0xff;
	//copy measured right track-sensor value inverted into compare B register
	OCR1B=gyCurRgtTrkSnsVal;
}
//================================================================================
// interrupt handler, ad-conversion finished
// enable bit: register ADCSRA bit ADIE
// #define SIG_ADC _VECTOR(14)
//================================================================================
SIGNAL (SIG_ADC){
	//switch tracking led off
	//SFRX(PORTD,TRK_LED_L);
	//if left tracking sensor AD-Converter is selected
	if(SFRQ(ADMUX,MUX3_L|MUX2_L|MUX1_H|MUX0_H)){
		//store left track AD-converter value in global variable (used left-justified mode only needs reading ADCH)
		gyCurLftTrkSnsVal=ADCH;
		//OCR1A=ADCH;
		//now select right track sensor
		SFRX(ADMUX,MUX3_L|MUX2_L|MUX1_H|MUX0_L);
	}//if
	//if right tracking sensor AD-Converter is selected
	else{
		//store left track AD-converter value in global variable (used left-justified mode only needs reading ADCH)
		gyCurRgtTrkSnsVal=ADCH;
		//OCR1B=ADCH;
		//now select left track sensor
		SFRX(ADMUX,MUX3_L|MUX2_L|MUX1_H|MUX0_H);
	}//else
}