/** * Cricket v2 Ultrasound Control implementation. * @author David Moore */module UltrasoundControlM {    provides {        interface UltrasoundControl;    }}implementation {    /*     * Resets the timer that measures the number of microseconds until     * each incoming pulse of the ultrasound receiver.  The     * PulseDetected event will be generated for each rising edge of     * the pulse.  timeout specifies the number of microseconds before     * the timer is disabled, at which time the DetectorTimeout event     * is generated.     */    async command result_t UltrasoundControl.StartDetector(uint16_t timeout)    {        atomic {	    /* Enable ultrasonic receiver */	    //cbi(PORTB, 4);            /* Reset the counter to zero */            outp(0x00, TCNT1H);            outp(0x00, TCNT1L);            /* Set the maximum count */            __outw(OCR1AL, timeout);            /* Clear the input capture and output compare flags.  We don't             * use sbi() because that could possibly clear other pending             * interrupts that use the TIFR register. */            outp(1 << ICF1, TIFR);            outp(1 << OCF1A, TIFR);            /* Activate input capture noise canceler (0x80), select rising edge               capture (0x40), and use a prescaler factor of 8 (0x02) */            outp(0xC2, TCCR1B);            /* Enable the input capture and output compare interrupts */            sbi(TIMSK, TICIE1);            sbi(TIMSK, OCIE1A);        }        return SUCCESS;    }    /*     * Stops the ultrasound timer and prevents the generation of further     * events.     */    async command result_t UltrasoundControl.StopDetector()    {        atomic {            /* Disable the timer interrupts */            cbi(TIMSK, TICIE1);            cbi(TIMSK, OCIE1A);            /* Turn off the timer */            outp(0xC0, TCCR1B);	    /* Disable ultrasonic receiver */	    //sbi(PORTB,4);        }        return SUCCESS;    }    default async event result_t UltrasoundControl.PulseDetected(uint16_t time)    {        return SUCCESS;    }    default async event result_t UltrasoundControl.DetectorTimeout()    {        return SUCCESS;    }    /* When the timeout is reached, the timer is stopped and the     * DetectorTimeout event is generated. */    TOSH_INTERRUPT(SIG_OUTPUT_COMPARE1A) {        call UltrasoundControl.StopDetector();        signal UltrasoundControl.DetectorTimeout();    }    /* Upon receiving the rising edge of a pulse, generate an event     * with the captured time. */    TOSH_INTERRUPT(SIG_INPUT_CAPTURE1) {        signal UltrasoundControl.PulseDetected(__inw_atomic(ICR1L));    }    uint8_t cycle_count;        /*      * Generate a 150 us pulse of 40 KHz ultrasound using the transducer.     */    async command result_t UltrasoundControl.SendPulse() {        atomic {            cycle_count = 0;	    /* Enable ultrasonic trasmitter */	    cbi(PORTG,2);            /* Set the OC2 port to output */            cbi(PORTB, 7);            sbi(DDRB, 7);                        /* Disable the overflow interrupt */            cbi(TIMSK, TOIE2);            /* Reset the timer to 0 */            outp(0, TCNT2);            /* Set the timer frequency to 40 KHz (39.68 Khz with the 7.3 Mhz Crystal)*/            outp(0x5B, OCR2);            /* Enable the output compare interrupt */            sbi(TIMSK, OCIE2);            /* Enable the timer in CTC mode with toggling of OC2 at reset */            outp(0x19, TCCR2);        }        return SUCCESS;    }    command result_t UltrasoundControl.SetGain(uint8_t val) {	uint8_t i;	atomic {		TOSH_MAKE_CC_PDATA_OUTPUT();            	cbi(PORTB, 6);   		//enable pot control            	cbi(PORTB, 5);   		//send address bit (0 for pot A)            	cbi(PORTD, 7);            	sbi(PORTB, 6);            	cbi(PORTB, 6);   		//send the data MSB first   		for(i =0; i< 8; i++){       			if(val & 0x80){ //bit is 1            			sbi(PORTD, 7);       			} else {//bit is zero            			cbi(PORTD, 7);       			}         			//generate clock edge            		sbi(PORTB, 6);	            	cbi(PORTB, 6);       			//get next MSB       			val <<= 1;    		}    		//disable pot control            	sbi(PORTB, 5);	}	return SUCCESS;    }     TOSH_INTERRUPT(SIG_OUTPUT_COMPARE2) {        atomic {            cycle_count++;            /* We allow 12 cycles of the wave, or 6 periods.  At 25 us per period,               that makes a total pulse length of 150 us. */            if (cycle_count == 12) {                cbi(TIMSK, OCIE2);                outp(0x00, TCCR2);                outp(0x00, TCNT2);	    	/* Disable ultrasonic trasmitter */	    	sbi(PORTG,2);            }        }    }}