PIC18F1220ESLASHSOSQTP datasheet(157/308 Pages) MICROCHIP

157 / 308 page

DS39605F-page 155

PIC18F1220/1320

17.0

10-BIT ANALOG-TO-DIGITAL

CONVERTER (A/D) MODULE

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

seven inputs for the PIC18F1220/1320 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 to set

the GO/DONE bit immediately. When the GO/DONE bit

is set, the selected channel is sampled for the pro-

grammed acquisition time before a conversion is actu-

ally started. This removes the firmware overhead that

may have been required to allow for an acquisition

(sampling) period (see Register 17-3 and Section 17.3

“Selecting and Configuring Automatic Acquisition

Time”).

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

controls the operation of the A/D module. The

ADCON1 register, shown in Register 17-2, configures

the functions of the port pins. The ADCON2 register,

shown in Register 17-3, configures the A/D clock

source, programmed acquisition time and justification.

ADCON0: A/D CONTROL REGISTER 0

R/W-0

U-0

R/W-0

VCFG1

VCFG0

—

CHS2

CHS1

CHS0

GO/DONE

ADON

bit 7

bit 0

bit 7-6

VCFG<1:0>: Voltage Reference Configuration bits

bit 5

Unimplemented: Read as ‘0’

bit 4-2

CHS2:CHS0: Analog Channel Select bits

000

= Channel 0 (AN0)

001

= Channel 1 (AN1)

010

= Channel 2 (AN2)

011

= Channel 3 (AN3)

100

= Channel 4 (AN4)

101

= Channel 5 (AN5)

110

= Channel 6 (AN6)

111

= Unimplemented(1)

bit 1

GO/DONE: A/D Conversion Status bit

When ADON = 1:

= A/D conversion in progress

= A/D Idle

bit 0

ADON: A/D On bit

= A/D converter module is enabled

= A/D converter module is disabled

Note 1: Performing a conversion on unimplemented channels returns full-scale results.

Legend:

R = Readable bit

W = Writable bit

U = Unimplemented bit, read as ‘0’

-n = Value at POR

‘1’ = Bit is set

‘0’ = Bit is cleared

x = Bit is unknown

A/D VREF+A/D VREF-

AVDD

AVSS

External VREF+AVSS

AVDD

External VREF-

External VREF+

External VREF-

PIC18F1220E/SOSQTP Datasheet(PDF) 157 Page - Microchip Technology

PIC18F1220E/SOSQTP Datasheet(HTML) 157 Page - Microchip Technology

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL