Register Based Working Example

Set up AtoD


	//----- SETUP AtoD -----
	AD1PCFG = 0xFFFC;				//AN1:0 analog, reset digital
	AD1CHSbits.CH0SA = 0;			//Channel 0 positive input is AN0
	AD1CON1bits.SSRC = 7;			//Internal counter ends sampling and starts conversion (auto-convert)
	AD1CON1bits.ASAM = 1;			//Sampling begins when SAMP bit is set

	//The PIC32 can sample up to 1000ksps, but we don't need that.
	//We want to sample at 44.1kHz to give a Nyquist frequency of 22.05kHz. So 1 sample every 22.6757uS
	//
	//Set the ADC Conversion Clock (TAD)
	//TAD is the basic timng value of the AtoD .
	//TAD must be >= 83.33nS
	//A conversion takes 12 x TAD + the number of sampling TAD clocks specified by SAMC (i.e. the fastest possible conversion takes 13 x TAD)
	//	System clock of 80MHz and PBDIV = 2
	//	TPB = (1 / 80MHz) * 2 = 25ns (this is the time of the peripheral bus)
	//
	//	TAD = (TPB * 2) * (ADCS + 1) * 2
	//		TAD = 25ns * (# + 1)
	//		
	AD1CON3bits.ADCS = 11;			//TAD=11=600ns

	//Auto-Sample Time
	//Set number of TAD clock cycles between start of acquisition and the start of conversion.
	//SAMC=1=1TAD to SAMC=31=31TAD
	//Add this to the 12 TAD clock cycles a conversion takes and you have the total AtoD conversion time per input sample
	AD1CON3bits.SAMC = 25;			//SAMC=25=22.2uS

	IPC6bits.AD1IP = 6;    //AtoD1 Interrupt Priority
	IPC6bits.AD1IS = 3;    //AtoD1 Subpriority
	IFS1CLR = 2;           //Clear ADC interrupt flag
	IEC1bits.AD1IE = 1;    //ADC interrupt enable
	AD1CON1bits.ON = 1;    //ADC enable

Interrupt Per Read

void __ISR(_ADC_VECTOR, ipl6) ADCInterruptHandler()
{
	IFS1CLR = 2;		//Clear irq flag

	samples[sampleCounter++] = ADC1BUF0 - 512;
}

 

Library Based Working Example

Setting Up The AtoD

	//----- SETUP THE A TO D PINS -----
	//Pins have allready been set to digital in.  This next line not needed as OpenADC10 will do the job
	//mPORTBSetPinsAnalogIn(BIT_2 | BIT_3 | BIT_4 | BIT_8);				//Pins have allready been set to digital in, set these to analog (this updates AD1PCFG)

	CloseADC10();// ensure the ADC is off before setting the configuration
	OpenADC10(
			(ADC_MODULE_ON | ADC_IDLE_STOP | ADC_FORMAT_INTG16 | ADC_CLK_AUTO | ADC_AUTO_SAMPLING_ON | ADC_SAMP_ON), //AD1CON1 register
			(ADC_VREF_AVDD_AVSS | ADC_SCAN_ON | ADC_ALT_INPUT_OFF | ADC_SAMPLES_PER_INT_10),						//AD1CON2 register (SCAN_ON so that all enabled analog inputs are automatically scanned_
			(ADC_SAMPLE_TIME_31 | ADC_CONV_CLK_PB | ADC_CONV_CLK_32Tcy),											//AD1CON3 register (Sets sampling time - 31:32 makes it slow as possible)
			(ENABLE_AN4_ANA | ENABLE_AN3_ANA | ENABLE_AN2_ANA),														//AD1PCFG register << SET ANALOG PINS
			(0)																										//AD1CSSL register
			);
	EnableADC10();
Reading the values

void read_atod (void)
{
	WORD w_temp;
	
	w_temp = ReadADC10(2);

	w_temp = ReadADC10(3);
		
	w_temp = ReadADC10(4);
}

 

 

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