24AA01-ESLASHMSG datasheet(6/24 Pages) MICROCHIP

6 / 24 page

24AA01/24LC01B

DS21711C-page 6

 2003 Microchip Technology Inc.

3.6

Device Addressing

A control byte is the first byte received following the

Start condition from the master device. The control byte

consists of a four-bit control code. For the 24XX01, this

is set as ‘1010’ binary for read and write operations.

The next three bits of the control byte are ‘don’t care’s’

for the 24XX01.

The last bit of the control byte defines the operation to

be performed. When set to ‘1’, a read operation is

selected. When set to ‘0’, a write operation is selected.

Following the Start condition, the 24XX01 monitors the

SDA bus checking the device type identifier being

transmitted. Upon receiving a ‘1010’ code, the slave

device outputs an Acknowledge signal on the SDA line.

Depending on the state of the R/W bit, the 24XX01 will

select a read or write operation.

FIGURE 3-2:

CONTROL BYTE

ALLOCATION

Operation

Control

Code

Block Select

R/W

Read

1010

Block Address

Write

1010

Block Address

101

R/W

START

READ/WRITE

SLAVE ADDRESS

X = ‘Don’t care’.

24AA01-E/MSG Datasheet(PDF) 6 Page - Microchip Technology