CAT24WC66
FUNCTIONAL DESCRIPTION
The CAT24WC66 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. The
transfer is controlled by the Master device which
generates the serial clock and all START and STOP
conditions for bus access. The CAT24WC66 operates
as a Slave device. Both the Master device and Slave
device can operate as either transmitter or receiver, but
the Master device controls which mode is activated.
transfer all 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 pins are hardwired or left unconnected (for
hardware compatibility with CAT24WC16). When
hardwired, up to eight CAT24WC66 devices may be
addressed on a single bus system (refer to Device
Addressing ). When the pins are left unconnected, the
default values are zeros.
WP:
Write Protect
This input, when tied to GND, allows write operations to
the entire memory. When this pin is tied to Vcc, the top
1/4 array of memory is write protected. When left
floating, memory is unprotected.
PIN DESCRIPTIONS
SCL:
Serial Clock
The serial clock input clocks all data transferred into or
out of the device.
SDA:
Serial Data/Address
The bidirectional serial data/address pin is used to
tF
tLOW
SCL
tSU:STA
tHD:STA
tHD:DAT
tHIGH
Figure 1. Bus Timing
tR
tLOW
tSU:DAT
tSU:STO
SDA IN
tAA
SDA OUT
tDH
tBUF
Figure 2. Write Cycle Timing
SCL
SDA
8TH BIT
BYTE n
ACK
tWR
STOP
CONDITION
START
CONDITION
ADDRESS
Figure 3. Start/Stop Timing
SDA
SCL
START BIT
STOP BIT
Doc. No. 1037, Rev. H
4
CATALYST [ CATALYST SEMICONDUCTOR ]
