24AA02/24LC02B
3.6
Device Addressing
FIGURE 3-2:
START
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 24XX02 this
is set as
1010
binary for read and write operations.
The next three bits of the control byte are the block
select bits (B2, B1, B0). The block select bits are ‘don’t
care’s’ for the 24XX02.
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 24XX02 monitors
the SDA bus checking the device type identifier being
transmitted, upon a
1010
code the slave device out-
puts an acknowledge signal on the SDA line. Depend-
ing on the state of the R/W bit, the 24XX02 will select a
read or write operation.
Operation
Read
Write
Control
Code
Block Select
Block Address
Block Address
R/W
CONTROL BYTE
ALLOCATION
READ/WRITE
SLAVE ADDRESS
R/W
A
1
0
1
0
X
X
X
X = ‘Don’t care’
1010
1010
1
0
DS21709A-page 6
2002 Microchip Technology Inc.
ETC [ ETC ]
