PIC18F4685-ISLASHSP datasheet(454/484 Pages) MICROCHIP

454 / 484 page

PIC18F2682/2685/4682/4685

DS39761B-page 452

Preliminary

FIGURE 27-22:

A/D CONVERSION TIMING

TABLE 27-25: A/D CONVERSION REQUIREMENTS

131

130

132

BSF ADCON0, GO

A/D CLK(1)

A/D DATA

ADRES

ADIF

SAMPLE

OLD_DATA

SAMPLING STOPPED

DONE

NEW_DATA

(Note 2)

Note

If the A/D clock source is selected as RC, a time of TCY is added before the A/D clock starts.

This allows the SLEEP instruction to be executed.

This is a minimal RC delay (typically 100 ns), which also disconnects the holding capacitor from the analog input.

. . .

TCY

Param

No.

Symbol

Characteristic

Min

Max

Units

Conditions

130

TAD

A/D Clock Period

PIC18FXXXX

0.7

25.0(1)

μsTOSC based, VREF ≥ 3.0V

PIC18LFXXXX

1.4

25.0(1)

μsVDD = 2.0V;

TOSC based, VREF full range

PIC18FXXXX

—

μs

A/D RC mode

PIC18LFXXXX

—

μsVDD = 2.0V; A/D RC mode

131

TCNV

Conversion Time

(not including acquisition time) (Note 2)

TAD

132

TACQ

Acquisition Time (Note 3)

1.4

—

μs-40°C to +85°C

135

TSWC

Switching Time from Convert

→ Sample

—

(Note 4)

136

TAMP

Amplifier Settling Time (Note 5)

1—

μs

This may be used if the “new” input

voltage has not changed by more

than 1 LSb (i.e., 5 mV @ 5.12V)

from the last sampled voltage (as

stated on CHOLD).

Note 1:

The time of the A/D clock period is dependent on the device frequency and the TAD clock divider.

ADRES register may be read on the following TCY cycle.

The time for the holding capacitor to acquire the “New” input voltage when the voltage changes full scale

after the conversion (AVDD to AVSS or AVSS to AVDD). The source impedance (

RS) on the input channels is

Ω.

On the following cycle of the device clock.

See Section 19.0 “10-Bit Analog-to-Digital Converter (A/D) Module” for minimum conditions when input

voltage has changed more than 1 LSb.

PIC18F4685-I/SP Datasheet(PDF) 454 Page - Microchip Technology

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