AD7992(RevPrH) 查看數據表（PDF） - Analog Devices

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AD7992
(Rev.:RevPrH)

2-Channel, 12-Bit ADC with I2C Compatible Interface in 10-Lead MSOP

Analog Devices 

AD7992

PRELIMINARY TECHNICAL DATA

INTERNAL REGISTER STRUCTURE

The AD7992 contains eleven internal registers, as shown

in Figure 9, that are used to store conversion results, high

and low conversion limits, and to configure and control

the device. Ten are data registers and one is an address

pointer register.

CONVERSION

RESULT REGISTER

ALERT STATUS

REGISTER

CONFIGURATION

REGISTER

ADDRESS

POINTER

REGISTER

CYCLE TIMER

D

REGISTER

A

T

DATALOW

REGISTER CH1

A

DATAHIGH

REGISTER CH1

HYSTERESIS

REGISTER CH1

HYSTERESIS

REGISTER CH2

DATALOW

REGISTER CH2

DATAHIGH

REGISTER CH2

SERIAL BUS INTERFACE

SDA

SCL

Figure 9. AD7992 Register Structure

Each data register has an address which is pointed to by

the Address Pointer register when communicating with it.

The Conversion Result Register is the only data register

that is read only.

ADDRESS POINTER REGISTER

The Address Pointer register itself does not have, nor does

it require, an address, as it is the register to which the first

data byte of every Write operation is written automatically.

The Address Pointer Register is an 8-bit register in which

the four LSBs are used as pointer bits to store an address

that points to one of the data registers of the AD7992,

while the four MSBs are used as command bits when us-

ing Mode 2 (see Modes of Operation section). The first

byte following each write address is the address of one of

the data registers, which is stored in the Address Pointer

Register, and selects the data register to which subsequent

data bytes are written. Only the four LSBs of this register

are used to select a data register. On Power up the Ad-

dress Point register contains all 0’s, therefore it is pointing

to the Conversion Result Register.

Table II. Address Pointer Register

C4 C3 C2 C1 P3 P2 P1 P0

0

0

0

0

Register Select

Table III. AD7992 Register Addresses

P3 P2 P1 P0

Registers

0 0 0 0 Conversion Result Register (Read)

0 0 0 1 Alert Status Register (Read/Write)

0 0 1 0 Configuration Register (Read/Write)

0 0 1 1 Cycle Timer Register (Read/Write)

0 1 0 0 DATALOW Reg CH1 (Read/Write)

0 1 0 1 DATAHIGH Reg CH1 (Read/Write)

0 1 1 0 Hysteresis Reg CH1 (Read/Write)

0 1 1 1 DATALOW Reg CH2 (Read/Write)

1 0 0 0 DATAHIGH Reg CH2 (Read/Write)

1 0 0 1 Hysteresis Reg CH2 (Read/Write)

CONFIGURATION REGISTER

The Configuration Register is an 8-bit read/write register that is used to set the operating modes of the AD7992. The

MSB is used, and is a Don’t Care bit. The bit functions are outlined in Table IV.

Table IV. Configuration Register Bit Function Description

D7

D6

D5 D4

D3

DONTC Single/Dual CH2 CH1 FLTR

0*

0*

0* 0*

1*

*Default settings at Power-up

D2

ALERT EN

0*

D1

BUSY/ALERT

0*

D0

ALERT/BUSY POLARITY

0*

–12–

REV. PrH

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