//Compiler: Codevision 1.24.6 //Target: ATmega8 //Clock frequency: 15.36Mhz //Author: Brody Radford - www.heythatsneat.org #include #include #include #define MAXFWD 10 #define MAXREV -10 #define OFF 0 #define lightOn() PORTD.4 = 0 #define lightOff() PORTD.4 = 1 #define TGint 0b10000000 //timer gate pin #define CLKint 0b01000000 //phase clock 1 #define readyScan() GICR = TGint #define startScan() GICR = TGint | CLKint #define stopScan() GICR = 0 #define LED PORTD.7 #define grnLED PORTB.5 #define redLED PORTB.4 #define ADCSTART 0b01000000 #define CH0 0 #define CH7 7 signed int pxlCount, //Pixel clock divisor counter pxlDiv = 7, //Pixel clock divisor pxlData[255], //Image data lineThreshold = 100, //"dark" level lineLeft, //Index of left edge lineRight, //Index of right edge pxlDataIndex, //Image data index foo, //??? light = 62, //Light level dark = 120, //Dark level bottom = 5, //Image bottom top = 190, //Image top centre = 95, //Image centre = top/2 error, //Distance from image centre to line centre speedLeft, //Left motor speed speedRight, //Right motor speed width; //Width of line unsigned int pxlStart = 180, //Yay, first useful pixels! pxlEnd = 1900, //No more useful pixels here clkCount; //Pixel clock counter float lightAvg = 0; //Flags char fCal = 1, fTx, //Transmit image if true fBusy = 1; // Speed range is +/- 10 speedR(signed char speedL) { OCR1AL = speedL+90; } speedL(signed char speedR) { OCR1BL = speedR+90; } interrupt [EXT_INT1] TG_START() { lightOn(); //And there was light... clkCount = 0; pxlDataIndex = 0; pxlCount = 0; startScan(); grnLED=!grnLED; //blink the led } interrupt [EXT_INT0] Clock() { // ************ Count the clock pulse ********* clkCount++; // ************ Useful pixel range ************ if((clkCount >= pxlStart) && (clkCount <= pxlEnd)) { // ******** Measure pixels ******** if(pxlCount > pxlDiv) //every pxlDiv-th pixel { ADCSRA |= ADCSTART; //start adc pxlCount = 0;//new measurement }else pxlCount++; } // *********** Measurement cycle complete ********* if(clkCount > pxlEnd) { stopScan(); fBusy = 0; } } interrupt [USART_RXC] rx() { foo = UDR; //flush buffer fTx = 1; } interrupt [ADC_INT] adcDone() { pxlData[pxlDataIndex] = ADCH; pxlDataIndex++; } interrupt [TIM2_COMP] t2Cmp() { } interrupt [TIM0_OVF] t0_ovf() { } main() { unsigned char count; //LEDs DDRB.5 = 1; //grn led DDRB.4 = 1; //red led DDRD.5 = 1; //led - DDRD.7 = 1; //led + //Camera lights DDRD.4 = 1; // TCCR0 = 0b00000101; // 1024 pre // TIMSK = 0b10000001; //T0 overflow int on // TCCR2 = 0b01111001; // DDRB.3 = 1; // OCR2 = 0; //UART UCSRA = 0; UCSRB = 0b10011000;//tx and rx en, rx int en UCSRC = 0b10000110; UBRRL = 24; //38400 //Servos TCCR1A = 0b10100011; //10-bit fast pwm, toggle OC pins, 58.6Hz pwm frequency, 16.7us timer tick TCCR1B = 0b00001100; //256 prescaler DDRB.1 = 1; //oc1a DDRB.2 = 1; //oc1b speedL(OFF); speedR(OFF); //ADC ADMUX = 0b00100000 | CH0; ADCSRA = 0b10001000; //enable ADC, int on //External ints MCUCR = 0b00001111; //rising edge SREG.7 = 1; //Global ints on // ******* calibrate light level ********* // while(1) // { // if(fTx) // { // fTx = 0; // lightOn(); // //delay_ms(500); // readyScan(); // //delay_ms(500); // while(fBusy); // // readyScan(); // // //delay_ms(100); // // while(fBusy); // // readyScan(); // // //delay_ms(100); // // while(fBusy); // redLED = 1; // for(pxlDataIndex=0; pxlDataIndex<250; pxlDataIndex++) // { // putchar(pxlData[pxlDataIndex]); // } // redLED = 0; // //Average middle of image // for(count = 50; count < 51; count++) // { // lightAvg = lightAvg + pxlData[count]; // } // } // } // lightAvg = pxlData[50]; // lightOn(); // while(lightAvg == 76); //Cool blinky trick // for(count = 0; count<3; count++) // { // lightOn(); // delay_ms(5); // lightOff(); // delay_ms(250); // } // lineThreshold = light + (dark - light)/2; // speedR(10); // speedL(10); readyScan(); while(1) { if(!fBusy) { fBusy = 1; // lightOff(); //save some battery //Flush debug vars for(count = 195; count<245; count++) pxlData[count] = 0; // *** Find line edges *** for(lineLeft = bottom; (pxlData[lineLeft] < lineThreshold) && (lineLeft <= top); lineLeft++); //left side for(lineRight = top; (pxlData[lineRight] < lineThreshold) && (lineRight >= bottom) ; lineRight--); //Right side // for(lineLeft = bottom; (pxlData[lineLeft] < lineThreshold); lineLeft++); //left side // for(lineRight = top; (pxlData[lineRight] < lineThreshold); lineRight--); //Right side width = lineRight - lineLeft; //Calculate error error = ((lineLeft + width/2) - centre)/15; //Limit error if(error>MAXFWD) error = MAXFWD; if(error 189) || (lineRight < 10)) //No line found { speedL(OFF); speedR(OFF); // speedL(-3); // speedR(-3); // delay_ms(3000); }else //Update motors { speedL(3+error); speedR(3-error); } //Debug vars pxlData[200] = lineLeft; pxlData[205] = lineRight; pxlData[210] = width; pxlData[215] = lineThreshold; pxlData[220] = error; pxlData[225] = lightAvg; //Spit out the data if(fTx) { fTx = 0; redLED = 1; for(pxlDataIndex=0; pxlDataIndex<250; pxlDataIndex++) { putchar(pxlData[pxlDataIndex]); } redLED = 0; } readyScan(); } } }