Specifications

Section 16. Analog-to-Digital Converter (ADC)

Example 16-3: Converting One Channel, Manual Sample Start,

AD Based Conversion Start Code

16.11.2.1 FREE RUNNING SAMPLE CONVERSION SEQUENCE

As shown in Figure 16-8, using the Auto-Convert Conversion Trigger mode (SSRC = 111) in

combination with the Auto-Sample Start mode (ASAM = 1), allows the ADC module to schedule

sample/conversion sequences with no intervention by the user or other device resources. This

“Clocked” mode allows continuous data collection after module initialization.

Figure 16-8: Converting One Channel, Auto-Sample Start, T

AD Based Conversion Start

Note: This A/D configuration must be enabled for the conversion rate of 750 ksps.

AD1PCFGL = 0xEFFF; // all PORTB = Digital; RB12 = analog

AD1CON1 = 0x00E0; // SSRC bit = 111 implies internal

// counter ends sampling and starts

// converting.

AD1CHS0= 0x000C; // Connect RB12/AN12 as CH0 input ..

// in this example RB12/AN12 is the input

AD1CSSL = 0;

AD1CON3 = 0x1F02; // Sample time = 31Tad, Tad = internal 2 Tcy

AD1CON2 = 0;

AD1CON1bits.ADON = 1; // turn ADC ON

while (1) // repeat continuously

{

AD1CON1bits.SAMP = 1; // start sampling then ...

// after 31Tad go to conversion

while (!AD1CON1bits.DONE);// conversion done?

ADCValue = ADC1BUF0; // yes then get ADC value

} // repeat

ADC Clock

SAMP

Buffer[1]

TSAMP

TCONV

DONE

= 16 TAD

TSAMP

TCONV

= 16 TAD

Buffer[0]

BSET AD1CON1,ASAM

Instruction Execution