11

CAT1640, CAT1641

Doc No. MD-3012, Rev. D

© 2009 SCILLC. All rights reserved.

Characteristics subject to change without notice.

Acknowledge Polling

Disabling of the inputs can be used to take advantage of

the typical write cycle time. Once the stop condition is

issued to indicate the end of the host’s write opration, the

CAT1640/41 initiates the internal write cycle. ACK polling

can be initiated immediately. This involves issuing the

start condition followed by the slave address for a write

operation. If the device is still busy with the write operation,

no ACK will be returned. If a write operation has

completed, an ACK will be returned and the host can

then proceed with the next read or write operation.

Read Operations

The READ operation for the CAT1640/41 is initiated in

the same manner as the write operation with one

exception, that R/

W bit is set to one. Three different

READ operations are possible: Immediate/Current

Address READ, Selective/Random READ and

Sequential READ.

SCL

SDA

8TH BIT

STOP

NO ACK

DATA OUT

89

SLAVE

ADDRESS

S

A

C

K

DATA

N

O

A

C

K

S

T

O

P

P

BUS ACTIVITY:

MASTER

SDA LINE

S

T

A

R

T

Figure 10. Immediate Address Read Timing