X24C01A
PIN DESCRIPTIONS
Serial Clock (SCL)
The SCL input is used to clock all data into and out of the
device.
Serial Data (SDA)
SDA is a bidirectional pin used to transfer data into and out
of the device. It is an open drain output and may be
wire-ORed with any number of open drain or open
collector outputs.
An open drain output requires the use of a pull-up
resistor. For selecting typical values, refer to the Guide-
lines for Calculating Typical Values of Bus Pull-Up
Resistors graph.
Address (A
0
, A
1
, A
2
)
The address inputs are used to set the least significant
three bits of the seven bit slave address. These inputs
can be static or actively driven. If used statically they must
be tied to V
SS
or V
CC
as appropriate. If actively
A
0
A
1
A
2
V
SS
PIN CONFIGURATION
DIP/SOIC
1
2
3
4
X24C01A
8
7
6
5
V
CC
WC
SCL
SDA
3841 FHD F02
PIN NAMES
Symbol
A
0
–A
2
SDA
SCL
WC
V
SS
V
CC
Description
Address Inputs
Serial Data
Serial Clock
Write Control
Ground
+5V
3841 PGM T01
driven, they must be driven to V
SS
or to V
CC
.
WRITE CONTROL (WC)
The Write Control input controls the ability to write to the
device. When WC is LOW (tied to V
SS
) the X24C01A will
be enabled to perform write operations. When WC is HIGH
(tied to V
CC
) the internal high voltage circuitry will
be disabled and all writes will be disabled.
DEVICE OPERATION
The X24C01A supports a bidirectional bus oriented
protocol. The protocol defines any device that sends
data onto the bus as a transmitter, and the receiving device
as the receiver. The device controlling the transfer is a
master and the device being controlled is the slave. The
master will always initiate data transfers and provide the
clock for both transmit and receive operations.
Therefore, the X24C01A will be considered a slave in
Clock and Data Conventions
Data states on the SDA line can change only during SCL
LOW. SDA state changes during SCL HIGH are re-
served for indicating start and stop conditions. Refer to
Figures 1 and 2.
Start Condition
All commands are preceded by the start condition,
which is a HIGH to LOW transition of SDA when SCL is
HIGH. The X24C01A continuously monitors the SDA and
SCL lines for the start condition and will not respond
to any command until this condition has been met.
all applications.
2
ICMIC [ IC MICROSYSTEMS ]
