AVRFreaks.net

#include <tiny26.h>
#include <delay.h>

#define FIRST_ADC_INPUT 0
#define LAST_ADC_INPUT 1
unsigned char adc_data[LAST_ADC_INPUT-FIRST_ADC_INPUT+1];
unsigned char value_1;
unsigned char value_2;
#define ADC_VREF_TYPE 0x20
// ADC interrupt service routine
// with auto input scanning
interrupt [ADC_INT] void adc_isr(void)
{
register static unsigned char input_index=0;
// Read the 8 most significant bits
// of the AD conversion result
adc_data[input_index]=ADCH;
// Select next ADC input
if (++input_index > (LAST_ADC_INPUT-FIRST_ADC_INPUT))
   input_index=0;
ADMUX=(FIRST_ADC_INPUT|ADC_VREF_TYPE)+input_index;
// Start the AD conversion
ADCSR|=0x40;
}

unsigned char temp;

// Declare your global variables here

void main(void)
{
// Declare your local variables here

// Input/Output Ports initialization
// Port A initialization
// Func7=In Func6=In Func5=In Func4=In Func3=In Func2=In Func1=In Func0=In
// State7=T State6=T State5=T State4=T State3=T State2=T State1=T State0=T
PORTA=0x00;
DDRA=0x00;

// Port B initialization
// Func7=In Func6=In Func5=In Func4=In Func3=Out Func2=In Func1=Out Func0=In
// State7=T State6=T State5=T State4=T State3=0 State2=T State1=0 State0=T
PORTB=0x00;
DDRB=0x0A;

// Timer/Counter 0 initialization
// Clock source: System Clock
// Clock value: Timer 0 Stopped
TCCR0=0x00;
TCNT0=0x00;

// Timer/Counter 1 initialization
// Clock source: System Clock
// Clock value: 500,000 kHz
// Mode: PWMA & B top=OCR1C
// OC1A output: Inverted, /OC1A disconnected
// OC1B output: Inverted, /OC1B disconnected
PLLCSR=0x00;
TCCR1A=0xF3;
TCCR1B=0x04;
TCNT1=0x00;
OCR1A=0xFF;
OCR1B=0xFF;
OCR1C=0xFF;

// External Interrupt(s) initialization
// INT0: Off
// Interrupt on any change on pins PA3, PA6, PA7 and PB4-7: Off
// Interrupt on any change on pins PB0-3: Off
GIMSK=0x00;
MCUCR=0x00;

// Timer(s)/Counter(s) Interrupt(s) initialization
TIMSK=0x00;

// Universal Serial Interface initialization
// Mode: Disabled
// Clock source: Register & Counter=no clk.
// USI Counter Overflow Interrupt: Off
USICR=0x00;

// Analog Comparator initialization
// Analog Comparator: Off
ACSR=0x80;

// ADC initialization
// ADC Clock frequency: 125,000 kHz
// ADC Voltage Reference: AREF
// Only the 8 most significant bits of
// the AD conversion result are used
ADMUX=FIRST_ADC_INPUT|ADC_VREF_TYPE;
ADCSR=0xCD;

// Global enable interrupts
#asm("sei")

while (1)
      {     
      value_1=adc_data[0];
      value_2=adc_data[1];
      if (value_1 == 0) value_1=1;
      if (value_2 == 0) value_2=1;
      temp=value_1*(1-(value_2/255));
      OCR1B=temp;
      };
}

temp=value_1*(1-(value_2/255));

temp=value_1-((unsigned)value_1 * value_2)/255;