24AA32A/24LC32A
7.0
PIN DESCRIPTIONS
The descriptions of the pins are listed in Table 7-1.
TABLE 7-1:
Name
A0
A1
A2
V
SS
SDA
SCL
WP
V
CC
PIN FUNCTION TABLE
PDIP
1
2
3
4
5
6
7
8
SOIC
1
2
3
4
5
6
7
8
TSSOP
1
2
3
4
5
6
7
8
MSOP
1
2
3
4
5
6
7
8
ROTATED
TSSOP
3
4
5
6
7
8
1
2
Description
Chip Address Input
Chip Address Input
Chip Address Input
Ground
Serial Address/Data I/O
Serial Clock
Write-Protect Input
+1.8V to 5.5V Power Supply
7.1
A0, A1, A2 Chip Address Inputs
7.3
Serial Clock (SCL)
The A0, A1, A2 inputs are used by the 24XX32A for
multiple device operation. The levels on these inputs
are compared with the corresponding bits in the slave
address. The chip is selected if the compare is true.
Up to eight devices may be connected to the same bus
by using different Chip Select bit combinations. These
inputs must be connected to either V
CC
or V
SS
.
The SCL input is used to synchronize the data transfer
to and from the device.
7.4
Write-Protect (WP)
7.2
Serial Data (SDA)
The WP pin can be connected to either V
SS
, V
CC
or left
floating. An internal pull-down resistor on this pin will
keep the device in the unprotected state if left floating.
If tied to V
SS
, or left floating, normal memory operation
is enabled (read/write the entire memory 000-FFF).
If tied to V
CC
, write operations are inhibited. Read
operations are not affected.
SDA is a bidirectional pin used to transfer addresses
and data into and out of the device. It is an open-drain
terminal, therefore, the SDA bus requires a pull-up
resistor to V
CC
(typical 10 kΩ for 100 kHz, 2 kΩ for
400 kHz)
For normal data transfer, SDA is allowed to change
only during SCL low. Changes during SCL high are
reserved for indicating Start and Stop conditions.
DS21713D-page 12
2003 Microchip Technology Inc.
MICROCHIP [ MICROCHIP TECHNOLOGY ]
