CAT1161/2
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
CAT1161/2 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 CAT1161/2 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.
protected and becomes read only. The CAT1161/2 will
accept both slave and byte addresses, but the memory
location accessed is protected from programming by the
device’s failure to send an acknowledge after the first
byte of data is received.
Read Operations
The READ operation for the CAT1161/2 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.
WRITE PROTECTION
The Write Protection feature allows the user to protect
against inadvertent memory array programming. If the
WP pin is tied to V
CC
, the entire memory array is
Figure 9. Immediate Address Read Timing
BUS ACTIVITY:
MASTER
SDA LINE
S
T
A
R
T
S
SLAVE
ADDRESS
S
T
O
P
P
A
C
K
DATA
N
O
A
C
K
SCL
8
9
SDA
8TH BIT
DATA OUT
NO ACK
STOP
9
Doc No. 3002, Rev. D
CATALYST [ CATALYST SEMICONDUCTOR ]
