PIC18F4550-IP Datasheet, PDF (267/438 Pages) Microchip Technology – 28/40/44-Pin, High-Performance, Enhanced Flash, USB Microcontrollers with nanoWatt Technology

PIC18F2455/2550/4455/4550
21.0 10-BIT ANALOG-TO-DIGITAL
CONVERTER (A/D) MODULE
The Analog-to-Digital (A/D) converter module has
10 inputs for the 28-pin devices and 13 for the
40/44-pin devices. This module allows conversion of an
analog input signal to a corresponding 10-bit digital
number.
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 21-1,
controls the operation of the A/D module. The
ADCON1 register, shown in Register 21-2, configures
the functions of the port pins. The ADCON2 register,
shown in Register 21-3, configures the A/D clock
source, programmed acquisition time and justification.
REGISTER 21-1: ADCON0: A/D CONTROL REGISTER 0
U-0
—
bit 7
U-0
R/W-0
R/W-0
R/W-0
—
CHS3
CHS2
CHS1
R/W-0
CHS0
R/W-0
GO/DONE
R/W-0
ADON
bit 0
Legend:
R = Readable bit
-n = Value at POR
W = Writable bit
‘1’ = Bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared
x = Bit is unknown
bit 7-6
bit 5-2
bit 1
bit 0
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)^(1,2)
0110 = Channel 6 (AN6)^(1,2)
0111 = Channel 7 (AN7)^(1,2)
1000 = Channel 8 (AN8)
1001 = Channel 9 (AN9)
1010 = Channel 10 (AN10)
1011 = Channel 11 (AN11)
1100 = Channel 12 (AN12)
1101 = Unimplemented⁽²⁾
1110 = Unimplemented⁽²⁾
1111 = Unimplemented⁽²⁾
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
Note 1: These channels are not implemented on 28-pin devices.
2: Performing a conversion on unimplemented channels will return a floating input measurement.
© 2009 Microchip Technology Inc.
DS39632E-page 265