38.3.6 Selecting the Scanned Inputs

• A Class 3 input. For Class 3 inputs, scan is the only mechanism for conversion.
• A Class 2 input that has the scan trigger selected as the trigger source by selecting the STRIG option in the TRGSRCx[4:0] bits located in the ADCTRG1 through ADCTRG8 registers.

int main(int argc, char** argv) {
int result[3];

/* Configure ADCCON1 */
ADCCON1 = 0;              // No ADCCON1 features are enabled including: Stop-in-Idle, turbo,
// CVD mode, Fractional mode and scan trigger source. ADCCON1bits.SELRES = 3;   // ADC7 resolution is 12 bits
ADCCON1bits.STRGSRC = 1;  // Select scan trigger.

/* Configure ADCCON2 */
ADCCON2bits.SAMC = 5;     // ADC7 sampling time = 5 * TAD7
ADCCON2bits.ADCDIV = 1;   // ADC7 clock freq is half of control clock = TAD7

/* Initialize warm up time register */ ADCANCON = 0;
ADCANCONbits.WKUPCLKCNT = 5; // Wakeup exponent = 32 * TADx

/* Clock setting */
ADCCON3bits.ADCSEL = 0;       // Select input clock source
ADCCON3bits.CONCLKDIV = 1;    // Control clock frequency is half of input clock
ADCCON3bits.VREFSEL = 0;      // Select AVDD and AVSS as reference source

ADC0TIMEbits.ADCDIV = 1;      // ADC0 clock frequency is half of control clock = TAD0
ADC0TIMEbits.SAMC = 5;        // ADC0 sampling time = 5 * TAD0
ADC0TIMEbits.SELRES = 3;      // ADC0 resolution is 12 bits

/* Select analog input for ADC modules, no presync trigger, not sync sampling */ ADCTRGMODEbits.SH0ALT = 0;    // ADC0 = AN0

/* Select ADC input mode */
ADCIMCON1bits.SIGN0 = 0;      // unsigned data format ADCIMCON1bits.DIFF0 = 0;      // Single ended mode ADCIMCON1bits.SIGN8 = 0;      // unsigned data format ADCIMCON1bits.DIFF8 = 0;      // Single ended mode ADCIMCON1bits.SIGN40 = 0;     // unsigned data format ADCIMCON1bits.DIFF40 = 0;     // Single ended mode

/* Configure ADCGIRQENx */
ADCGIRQEN1 = 0;               // No interrupts are used. ADCGIRQEN2 = 0;

/* Configure ADCCSSx */
ADCCSS1 = 0;                 // Clear all bits
ADCCSS2 = 0;
ADCCSS1bits.CSS0 = 1;         // AN0 (Class 1) set for scan ADCCSS1bits.CSS8 = 1;         // AN8 (Class 2) set for scan ADCCSS2bits.CSS40 = 1;        // AN40 (Class 3) set for scan

/* Configure ADCCMPCONx */
ADCCMPCON1 = 0;               // No digital comparators are used. Setting the ADCCMPCONx ADCCMPCON2 = 0;               // register to '0' ensures that the comparator is disabled. ADCCMPCON3 = 0;               // Other registers are ‘don't care’.
ADCCMPCON4 = 0;
ADCCMPCON5 = 0; ADCCMPCON6 = 0;

/* Configure ADCFLTRx */
ADCFLTR1 = 0;                // No oversampling filters are used. ADCFLTR2 = 0;
ADCFLTR3 = 0; ADCFLTR4 = 0; ADCFLTR5 = 0; ADCFLTR6 = 0; 
/* Set up the trigger sources */
ADCTRG1bits.TRGSRC0 = 3;      // Set AN0 (Class 1) to trigger from scan source
ADCTRG3bits.TRGSRC8 = 3;      // Set AN8 (Class 2) to trigger from scan source
// AN40 (Class 3) always uses scan trigger source

/* Early interrupt */
ADCEIEN1 = 0;                // No early interrupt
ADCEIEN2 = 0;

/* Turn the ADC on */ ADCCON1bits.ON = 1;

/* Wait for voltage reference to be stable */
while(!ADCCON2bits.BGVRRDY); // Wait until the reference voltage is ready while(ADCCON2bits.REFFLT);   // Wait if there is a fault with the reference voltage

/* Enable clock to analog circuit */
ADCANCONbits.ANEN0 = 1;       // Enable the clock to analog bias ADC0
ADCANCONbits.ANEN7 = 1;       // Enable, ADC7

/* Wait for ADC to be ready */
while(!ADCANCONbits.WKRDY0);     // Wait until ADC0 is ready while(!ADCANCONbits.WKRDY7);     // Wait until ADC7 is ready

/* Enable the ADC module */
ADCCON3bits.DIGEN0 = 1;          // Enable ADC0
ADCCON3bits.DIGEN7 = 1;          // Enable ADC7

while (1) {
/* Trigger a conversion */ ADCCON3bits.GSWTRG = 1;

/* Wait the conversions to complete */
while (ADCDSTAT1bits.ARDY0 == 0);
/* fetch the result */
result[0] = ADCDATA0;

while (ADCDSTAT1bits.ARDY8 == 0);
/* fetch the result */
result[1] = ADCDATA8;

while (ADCDSTAT2bits.ARDY40 == 0);
/* fetch the result */
result[2] = ADCDATA40;

/*
* Process results here
*
*
*/
}
return (1);
}