PIC18F2423-E/ML View Datasheet(PDF) - Microchip Technology

Part Name

Description

Manufacturer

PIC18F2423-E/ML

28/40/44-Pin, Enhanced Flash Microcontrollers with 12-Bit A/D and nanoWatt Technology

Microchip Technology 

PIC18F2423/2523/4423/4523

2.0 12-BIT ANALOG-TO-DIGITAL

CONVERTER (A/D) MODULE

The Analog-to-Digital (A/D) Converter module has

10 inputs for the PIC18F2423/2523 devices and 13 for

the PIC18F4423/4523 devices. This module allows

conversion of an analog input signal to a corresponding

12-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)

Of the ADCONx registers:

• ADCON0 (shown in Register 2-1) – Controls the

module’s operation

• ADCON1 (Register 2-2) – Configures the

functions of the port pins

• ADCON2 (Register 2-3) – Configures the A/D

clock source, programmed acquisition time and

justification

REGISTER 2-1: 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’

CHS<3:0>: 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 PIC18F2423/2523 devices.

2: Performing a conversion on unimplemented channels will return a floating input measurement.

© 2009 Microchip Technology Inc.

DS39755C-page 25

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