MB85RC64A

DS501-00019-5v2-E

5



DEVICE ADDRESS WORD (Slave address)

Following the start condition, the master sends the 8 bits device address word to start I2C communication.

The device address word (8 bits) consists of a device Type code (4 bits), device address code (3 bits), and

a read/write code (1 bit).

• Device Type Code (4 bits)

The upper 4 bits of the device address word are a device type code that identifies the device type, and are

fixed at “1010” for the MB85RC64A.

• Device Address Code (3 bits)

Following the device type code, the 3 bits of the device address code are input in order of A2, A1 and A0.

The device address code identifies one device from up to eight devices connected to the bus.

Each MB85RC64A is given a unique 3 bits code on the device address pin (external hardware pin A2, A1

and A0). The slave only responds if the received device address code is equal to this unique 3 bits code.

• Read/Write Code (1 bit)

The 8th bit of the device address word is the R/W (read/write) code. When the R/W code is “0”, a write

operation is enabled, and the R/W code is “1”, a read operation is enabled for the MB85RC64A.

It turns to a stand-by state if the device code is not “1010” or device address code does not equal to pins

A2, A1 and A0.



Device Address Word

..

..

Start

ACK (SDA is the "L" level)

1234567891

2

SCL

SDA

ACK

Start Condition

Device Code

Device Address Code Read/Write Code

A

S

S

10

1

0

A2

A1

A0

R/W

A

Access from master

Access from slave