Specifications

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

Example 16-1: Converting 1 Channel, Manual Sample Start,

Manual Conversion Start Code

Figure 16-6 is an example where setting the ASAM bit initiates automatic sampling and clearing

the SAMP bit terminates sampling and starts conversion. After the conversion completes, the

ADC module automatically returns to a sampling state. The SAMP bit is automatically set at the

start of the sample interval. The user software must time the clearing of the SAMP bit to ensure

adequate sampling time of the input signal, understanding that the time between clearing of the

SAMP bit includes the conversion time as well as the sampling time. See Example 16-2 for code

example.

Figure 16-6: Converting 1 Channel, Automatic Sample Start, Manual Conversion Start

AD1PCFGL = 0xFFFB; // all PORTB = Digital; RB2 = analog

AD1CON1 = 0x0000; // SAMP bit = 0 ends sampling ...

// and starts converting

AD1CHS0 = 0x0002; // Connect RB2/AN2 as CH0 input ..

// in this example RB2/AN2 is the input

AD1CSSL = 0;

AD1CON3 = 0x0002; // Manual Sample, Tad = internal 2 Tcy

AD1CON2 = 0;

AD1CON1bits.ADON = 1; // turn ADC ON

while (1) // repeat continuously

{

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

DelayNmSec(100); // for 100 mS

AD1CON1bits.SAMP = 0; // start Converting

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

ADCValue = ADC1BUF0; // yes then get ADC value

} // repeat

ADC Clock

SAMP

ADC1BUF0

TSAMP

TCONV

BCLR AD1CON1,SAMP

Instruction Execution

TCONV

BSET AD1CON1,ASAM BCLR AD1CON1,SAMP

TSAMP

TAD0 TAD0

DONE