Datasheet

 1999-2013 Microchip Technology Inc. Preliminary DS41124D-page 91

PIC16C745/765

12.0 ANALOG-TO-DIGITAL

CONVERTER (A/D) MODULE

The 8-bit Analog-To-Digital (A/D) converter module has

five inputs for the PIC16C745 and eight for the

PIC16C765.

The A/D allows conversion of an analog input signal to

a corresponding 8-bit digital value. The output of the

sample and hold is the input into the converter, which

generates the result via successive approximation. The

analog reference voltage is software selectable to

either the device’s positive supply voltage (V

DD) or the

voltage level on the RA3/AN3/V

REF pin.

The A/D converter has a unique feature of being able

to operate while the device is in SLEEP mode. To oper-

ate in sleep, the A/D conversion clock must be derived

from the A/D’s dedicated internal RC oscillator.

The A/D module has three registers. These registers

are:

• A/D Result Register (ADRES)

• A/D Control Register 0 (ADCON0)

• A/D Control Register 1 (ADCON1)

The ADCON0 register, shown in Register 12-1, con-

trols the operation of the A/D module. The ADCON1

tions of the port pins. The port pins can be configured

as analog inputs (RA3 can also be a voltage reference)

or as digital I/O.

Additional information on using the A/D module can be

found in the PIC Mid-Range MCU Family Reference

Manual (DS33023) and in Application Note, AN546.

Note: In order to maintain 8-bit A/D accuracy,

ADCS<1:0> must be set to either F

INT/32 or

RC. Choosing FINT/8 or FINT/2 will cause

loss of accuracy, due to the USB module’s

requirement of running at 24 MHz.