PIC18F2420 MICROCHIP [Microchip Technology], PIC18F2420 Datasheet - Page 228

• Manufacturer Part Number: PIC18F2420
• Description: 28/40/44-Pin Enhanced Flash Microcontrollers with 10-Bit A/D and nanoWatt Technology
• Manufacturer: MICROCHIP [Microchip Technology]

PIC18F2420/2520/4420/4520
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 oper-
ate 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.
FIGURE 19-1:
DS39631A-page 226
REF
DD
+ and RA2/AN2/V
and V
Note 1:
SS
2:
), or the voltage level on the RA3/AN3/
Converter
10-Bit
Channels AN5 through AN7 are not available on 28-pin devices.
I/O pins have diode protection to V
A/D
Reference
Voltage
A/D BLOCK DIAGRAM
REF
-/CV
REF
pins.
V
V
REF
REF
+
-
(Input Voltage)
VCFG1:VCFG0
V
AIN
Preliminary
DD
and V
X
X
1
0
0
1
X
X
V
SS
DD
A device Reset forces all registers to their Reset state.
This forces the A/D module to be turned off and any
conversion in progress is aborted.
Each port pin associated with the A/D converter can be
configured as an analog input, 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 com-
plete, the result is loaded into the ADRESH:ADRESL
register pair, the GO/DONE bit (ADCON0 register) is
cleared and A/D Interrupt Flag bit, ADIF, is set. The block
diagram of the A/D module is shown in Figure 19-1.
.
V
SS
CHS3:CHS0
1100
1011
1010
1001
1000
0111
0110
0101
0100
0011
0010
0001
0000
 2004 Microchip Technology Inc.
AN12
AN11
AN10
AN9
AN8
AN7
AN6
AN5
AN4
AN3
AN2
AN1
AN0
(1)
(1)
(1)