PIC18F2220 MICROCHIP [Microchip Technology], PIC18F2220 Datasheet - Page 213

• Manufacturer Part Number: PIC18F2220
• Description: 28/40/44-Pin High-Performance, Enhanced Flash Microcontrollers with 10-Bit A/D and nanoWatt Technology
• Manufacturer: MICROCHIP [Microchip Technology]

19.0
The Analog-to-Digital (A/D) converter module has 10
inputs for the PIC18F2X20 devices and 13 for the
PIC18F4X20 devices. This module allows conversion
of an analog input signal to a corresponding 10-bit
digital number.
A new feature for the A/D converter is the addition of
programmable acquisition time. This feature allows the
user to select a new channel for conversion and setting
the GO/DONE bit immediately. When the GO/DONE bit is
set, the selected channel is sampled for the programmed
acquisition time before a conversion is actually started.
This removes the firmware overhead that may have been
required to allow for an acquisition (sampling) period (see
Register 19-3
Configuring Automatic Acquisition Time”).
REGISTER 19-1:
 2003 Microchip Technology Inc.
10-BIT ANALOG-TO-DIGITAL
CONVERTER (A/D) MODULE
bit 7-6
bit 5-3
bit 1
bit 0
and
Section 19.3
ADCON0 REGISTER
Legend:
R = Readable bit
- n = Value at POR
Unimplemented: Read as ‘0’
CHS3:CHS0: Analog Channel Select bits
0000 = Channel 0 (AN0)
0001 = Channel 1 (AN1)
0010 = Channel 2 (AN2)
0011 = Channel 3 (AN3)
0100 = Channel 4 (AN4)
0101 = Channel 5 (AN5)
0110 = Channel 6 (AN6)
0111 = Channel 7 (AN7)
1000 = Channel 8 (AN8)
1001 = Channel 9 (AN9)
1010 = Channel 10 (AN10)
1011 = Channel 11 (AN11)
1100 = Channel 12 (AN12)
1101 = Unimplemented
1110 = Unimplemented
1111 = Unimplemented
GO/DONE: A/D Conversion Status bit
When ADON = 1:
1 = A/D conversion in progress
0 = A/D Idle
ADON: A/D On bit
1 = A/D converter module is enabled
0 = A/D converter module is disabled
bit 7
Note 1: These channels are not implemented on the PIC18F2X20 (28-pin) devices.
U-0
—
2: Performing a conversion on unimplemented channels returns full-scale results.
“Selecting
U-0
—
PIC18F2220/2320/4220/4320
(2)
(2)
(2)
(1,2)
(1,2)
(1,2)
R/W-0
CHS3
and
W = Writable bit
‘1’ = Bit is set
R/W-0
CHS2
The module has five registers:
• A/D Result High Register (ADRESH)
• A/D Result Low Register (ADRESL)
• A/D Control Register 0 (ADCON0)
• A/D Control Register 1 (ADCON1)
• A/D Control Register 2 (ADCON2)
The ADCON0 register, shown in Register 19-1,
controls the operation of the A/D module. The
ADCON1 register, shown in Register 19-2, configures
the functions of the port pins. The ADCON2 register,
shown in Register 19-3, configures the A/D clock
source, programmed acquisition time and justification.
R/W-0
CHS1
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared
R/W-0
CHS0
GO/DONE
x = Bit is unknown
R/W-0
DS39599C-page 211
ADON
R/W-0
bit 0