CAT24C32

6

Doc. No. 1101, Rev. G

© 2007 by Catalyst Semiconductor, Inc.

Characteristics subject to change without notice

WRITE OPERATIONS

Byte Write

To write data to memory, the Master creates a START

condition on the bus and then broadcasts a Slave ad-

dress with the R/W

dress with the R/

dress with the R/ bit set to ‘0’. The Master then sends

W

W

two address bytes and a data byte and concludes the

session by creating a STOP condition on the bus. The

Slave responds with ACK after every byte sent by the

Master (Figure 5). The STOP starts the internal Write

SDA output is tri-stated and the Slave does not acknowl-

edge the Master (Figure 6).

Page Write

The Byte Write operation can be expanded to Page

Write, by sending more than one data byte to the Slave

before issuing the STOP condition (Figure 7). Up to 32

distinct data bytes can be loaded into the internal Page

Write Buffer starting at the address provided by the

Master. The page address is latched, and as long as the

Master keeps sending data, the internal byte address is

incremented up to the end of page, where it then wraps

around (within the page). New data can therefore replace

data loaded earlier. Following the STOP, data loaded

during the Page Write session will be written to memory

Acknowledge Polling

As soon (and as long) as internal Write is in progress,

the Slave will not acknowledge the Master. This feature

enables the Master to immediately follow-up with a new

Read or Write request, rather than wait for the maximum

NoACK response from the Slave, the Master simply re-

peats the request until the Slave responds with ACK.

Hardware Write Protection

WiththeWPpinheldHIGH,theentirememoryisprotected

against Write operations. If the WP pin is left floating or

is grounded, it has no impact on the Write operation. The

state of the WP pin is strobed on the last falling edge

8). If the WP pin is HIGH during the strobe interval, the

Slave will not acknowledge the data byte and the Write

request will be rejected.

Delivery State

The CAT24C32 is shipped erased, i.e., all bytes are

FFh.