CAT24C164

8

Doc. No. 1118, Rev. A

© 2006 by Catalyst Semiconductor, Inc.

Characteristics subject to change without notice

READ OPERATIONS

Immediate Read

Upon receiving a Slave address with the R/W

Upon receiving a Slave address with the R/

Upon receiving a Slave address with the R/

bit set to

W

W

‘1’, the CAT24C164 will interpret this as a request for

data residing at the current byte address in memory.

The CAT24C164 will acknowledge the Slave address,

will immediately shift out the data residing at the current

address, and will then wait for the Master to respond.

If the Master does not acknowledge the data (NoACK)

and then follows up with a STOP condition (Figure 9),

the CAT24C164 returns to Standby mode.

Selective Read

Selective Read operations allow the Master device to

select at random any memory location for a read opera-

tion. The Master device first performs a ‘dummy’ write

operation by sending the STARTcondition, slave address

and byte address of the location it wishes to read. After

the CAT24C164 acknowledges the byte address, the

Master device resends the START condition and the

slave address, this time with the R/W

slave address, this time with the R/

slave address, this time with the R/ bit set to one. The

W

W

CAT24C164 then responds with its acknowledge and

sends the requested data byte. The Master device does

not acknowledge the data (NoACK) but will generate a

STOP condition (Figure 10).

Sequential Read

If during a Read session, the Master acknowledges the

mitting data residing at subsequent locations until the

Master responds with a NoACK, followed by a STOP

(Figure 11). In contrast to Page Write, during Sequential

Read the address count will automatically increment to

and then wrap-around at end of memory (rather than

end of page).