CAT24WC01/02/04/08/16
FUNCTIONAL DESCRIPTION
The CAT24WC01/02/04/08/16 supports the I
2
C Bus
data transmission protocol. This Inter-Integrated Circuit
Bus protocol defines any device that sends data to the
bus to be a transmitter and any device receiving data to
be a receiver. Data transfer is controlled by the Master
device which generates the serial clock and all START
and STOP conditions for bus access. The CAT24WC01/
02/04/08/16 operates as a Slave device. Both the Mas-
ter and Slave devices can operate as either transmitter
or receiver, but the Master device controls which mode
is activated. A maximum of 8 devices (24WC01 and
24WC02), 4 devices (24WC04), 2 devices (24WC08)
and 1 device (24WC16) may be connected to the bus as
determined by the device address inputs A0, A1, and A2.
PIN DESCRIPTIONS
SCL:
Serial Clock
The CAT24WC01/02/04/08/16 serial clock input pin is
used to clock all data transfers into or out of the device.
This is an input pin.
SDA:
Serial Data/Address
The CAT24WC01/02/04/08/16 bidirectional serial data/
address pin is used to transfer data into and out of the
device. The SDA pin is an open drain output and can be
wire-ORed with other open drain or open collector
outputs.
A0, A1, A2:
Device Address Inputs
These inputs set device address when cascading mul-
tiple devices. When these pins are left floating the
default values are zeros (except for the 24WC01).
A maximum of eight devices can be cascaded when
Figure 1. Bus Timing
tF
tLOW
SCL
tSU:STA
tHD:STA
tHIGH
tLOW
tR
tHD:DAT
tSU:DAT
tSU:STO
SDA IN
tAA
SDA OUT
5020 FHD F03
tDH
tBUF
Figure 2. Write Cycle Timing
SCL
SDA
8TH BIT
BYTE n
ACK
tWR
STOP
CONDITION
START
CONDITION
ADDRESS
5020 FHD F04
Figure 3. Start/Stop Timing
SDA
SCL
5020 FHD F05
START BIT
Doc. No. 25051-00 3/98 S-1
STOP BIT
4
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