PIC18C242 MICROCHIP [Microchip Technology], PIC18C242 Datasheet - Page 169

• Manufacturer Part Number: PIC18C242
• Description: High-Performance Microcontrollers with 10-Bit A/D
• Manufacturer: MICROCHIP [Microchip Technology]

The analog reference voltage is software selectable to
either the device’s positive and negative supply voltage
(V
V
The A/D converter has a unique feature of being able to
operate while the device is in SLEEP mode. To operate
in sleep, the A/D conversion clock must be derived from
the A/D’s internal RC oscillator.
The output of the sample and hold is the input into the
converter, which generates the result via successive
approximation.
A device reset forces all registers to their reset state.
This forces the A/D module to be turned off and any
conversion is aborted.
FIGURE 16-1: A/D BLOCK DIAGRAM
REF
7/99 Microchip Technology Inc.
DD
+ pin and RA2/AN2/V
and V
Converter
10-bit
SS
A/D
) or the voltage level on the RA3/AN3/
Reference
voltage
REF
-.
V
V
REF
REF
-
+
(Input voltage)
V
AIN
PCFG0
Preliminary
V
DD
V
Each port pin associated with the A/D converter can
be configured as an analog input (RA3 can also be a
voltage reference) or as a digital I/O.
The ADRESH and ADRESL registers contain the result
of the A/D conversion. When the A/D conversion is
complete, the result is loaded into the ADRESH/
ADRESL registers, the GO/DONE bit (ADCON0<2>) is
cleared, and A/D interrupt flag bit ADIF is set. The block
diagram of the A/D module is shown in Figure 16-1.
SS
CHS2:CHS0
111
110
101
100
011
010
001
000
PIC18CXX2
DS39026B-page 169
AN1
AN7
AN2
AN0
AN6
AN5
AN4
AN3