ADT7411ARQZ10 查看數據表（PDF） - Analog Devices

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ADT7411ARQZ10

SPI®/I2C® Compatible, 10-Bit Digital Temperature Sensor and 8-Channel ADC

Analog Devices 

ADT7411

The I2C address set up by the ADD pin is not latched by

the device until after this address has been sent twice. On

the eighth SCL cycle of the second valid communication,

the serial bus address is latched in. This is the SCL cycle

directly after the device has seen its own I2C serial bus

address. Any subsequent changes on this pin will have no

effect on the I2C serial bus address.

Writing to the ADT7411

Depending on the register being written to, there are two dif-

ferent writes for the ADT7411. It is not possible to do a block

write to this part, i.e., no I2C auto-increment.

Writing to the Address Pointer Register for a Subsequent

Read

In order to read data from a particular register, the address

pointer register must contain the address of that register. If it

does not, the correct address must be written to the address

pointer register by performing a single-byte write operation, as

shown in Figure 34. The write operation consists of the serial

bus address followed by the address pointer byte. No data is

written to any of the data registers. A read operation is then

performed to read the register.

Writing Data to a Register

All registers are 8-bit registers so only one byte of data can be

written to each register. Writing a single byte of data to one of

these read/write registers consists of the serial bus address, the

data register address written to the address pointer register,

CS

A

B

(START HIGH)

followed by the data byte written to the selected data register.

This is illustrated in Figure 35. To write to a different register,

another START or repeated START is required. If more than

one byte of data is sent in one communication operation, the

addressed register will be repeatedly loaded until the last data

byte has been sent.

Reading Data From the ADT7411

Reading data from the ADT7411 is done in a one-byte

operation. Reading back the contents of a register is shown in

Figure 36. The register address had previously been set up by a

single-byte write operation to the Address Pointer register. To

read from another register, write to the Address Pointer register

again to set up the relevant register address. Thus, block reads

are not possible, i.e., no I2C auto-increment.

SPI Serial Interface

The SPI serial interface of the ADT7411 consists of four wires:

CS, SCLK, DIN, and DOUT. The CS is used to select the device

when more than one device is connected to the serial clock and

data lines. The CS is also used to distinguish between any two

separate serial communications (see Figure 41 for a graphical

explanation). The SCLK is used to clock data in and out of the

part. The DIN line is used to write to the registers, and the

DOUT line is used to read data back from the registers. The

recommended pull-up resistor value is between 500 Ω and

820 Ω.

C

SPI LOCKED ON

THIRD RISING EDGE

SPI FRAMING

EDGE

CS

(START LOW)

A

B

C

SPI LOCKED ON

THIRD RISING EDGE

Figure 33. Serial Interface—Selecting and Locking SPI Protocol

SPI FRAMING

EDGE

1

9

1

9

SCL

SDA

1

START BY

MASTER

0

0

1

A2 A1 A0 R/W

P7

FRAME 1

SERIAL BUS ADDRESS BYTE

ACK. BY

ADT7411

P6 P5 P4 P3 P2 P1 P0

FRAME 2

ADDRESS POINTER REGISTER BYTE

ACK. BY STOP BY

ADT7411 MASTER

Figure 34. I2C—Writing to the Address Pointer Register to Select a Register for a Subsequent Read Operation

Rev. A | Page 29 of 36

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