CAT1161 Catalyst Semiconductor, CAT1161 Datasheet - Page 9

• Manufacturer Part Number: CAT1161
• Description: Supervisory Circuits with I2C Serial CMOS EEPROM/ Precision Reset Controller and Watchdog Timer
• Manufacturer: Catalyst Semiconductor

Acknowledge Polling
Figure 9. Immediate Address Read Timing
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.
WRITE PROTECTION
The Write Protection feature allows the user to protect
against inadvertent memory array programming. If the
WP pin is tied to V
SDA
SCL
CC
, the entire memory array is
BUS ACTIVITY:
SDA LINE
MASTER
DATA OUT
8TH BIT
8
S
S
A
R
T
T
ADDRESS
SLAVE
9
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.
9
C
A
K
NO ACK
DATA
N
O
A
C
K
P
O
S
T
P
STOP
Doc No. 3002, Rev. D
CAT1161/2