AK9720 Datasheet, PDF(24/31 Page) Asahi Kasei Microsystems

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AK9720 Datasheet, PDF (24/31 Pages) Asahi Kasei Microsystems – IR Sensor Module with I2C I/F

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[AK9720]

1.4 Slave Address

The Slave address of the AK9720 can be selected from the following list by setting the

CAD0/1 pins.

When the CAD0/1 pins are connected to VSS, the Slave address bit is â0â. When the

CAD0/1 pins are connected to DVDD, the Slave address bit is â1â. Do not set up

âCAD1=CAD0=1â while the I2C interface is used, because the âCAD1=CAD0=1â state is

only for Analog Output Mode.

CAD1

CAD0

Slave Address

64H

65H

66H

Analog Output Mode Only

Table1. Setting CAD0/1 for Slave Address

When the first one byte data including the Slave address is transmitted after a Start

condition, the device, which is specified as the communicator by the Slave address on the

bus, is selected.

After transmitting the Slave address, the device that has the corresponding device

address will execute a instruction after transmitting an Acknowledge signal. The 8th bit

(Least Significant Bit-LSB) of the first one byte is the R/W bit.

When the R/W bit is set to â1â, a READ instruction is executed. When the R/W bit is set to

â0â, a WRITE instruction is executed.

MSB

LSB

1 CAD1 CAD0 R/W

Fig.4. Slave Address

1.5 WRITE Instruction

When the R/W bit is set to â0â, the AK9720 executes a WRITE Operation.

The AK9720 will output an Acknowledge signal and receive the second byte, after

receiving a Start condition and first one bit (Slave address) in a WRITE Operation. The

second byte has an MSB-first configuration, and specifies the address of the internal

control register.

MSB

LSB

A7 A6 A5 A4 A3 A2 A1 A0

Fig.5. Register Address

The AK9720 will generate an Acknowledge and receive the third byte after receiving the

second byte (Register Address).

The data after the third byte is the control data. The control data consists of 8-bits and has

an MSB-first configuration. The AK9720 generates an Acknowledge for each byte

received. The data transfer is terminated by the Stop condition, which is generated by the

Rev.02

AKM Confidential

- 24 -

2012/11

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