CAT1024 데이터 시트보기 (PDF) - ON Semiconductor
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CAT1024 Datasheet PDF : 23 Pages
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CAT1024, CAT1025
Page Write
The CAT1024/25 writes up to 16 bytes of data in a single
write cycle, using the Page Write operation. The page write
operation is initiated in the same manner as the byte write
operation, however instead of terminating after the initial
byte is transmitted, the Master is allowed to send up to 15
additional bytes. After each byte has been transmitted, the
CAT1024/25 will respond with an acknowledge and
internally increment the lower order address bits by one. The
high order bits remain unchanged.
If the Master transmits more than 16 bytes before sending
the STOP condition, the address counter ‘wraps around,’
and previously transmitted data will be overwritten.
When all 16 bytes are received, and the STOP condition
has been sent by the Master, the internal programming cycle
begins. At this point, all received data is written to the
CAT1024/25 in a single write cycle.
S
T
BUS ACTIVITY: A
MASTER R
T
SLAVE
ADDRESS
BYTE
ADDRESS
S
T
DATA
O
P
SDA LINE S
P
A
A
A
C
C
C
K
K
K
Figure 8. Byte Write Timing
S
T
BUS ACTIVITY: A
MASTER R
T
SDA LINE S
SLAVE
ADDRESS
BYTE
ADDRESS (n)
DATA n
A
A
A
C
C
C
K
K
K
Figure 9. Page Write Timing
DATA n + 1
A
C
K
S
T
DATA n+15 O
P
P
A
C
K
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 operation, the
CAT1024/25 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.
WRITE PROTECTION PIN (WP)
The Write Protection feature (CAT1025 only) allows the
user to protect against inadvertent memory array
programming. If the WP pin is tied to VCC, the entire
memory array is protected and becomes read only. The
CAT1025 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 CAT1024/25 is initiated in
the same manner as the write operation with one exception,
the R/W bit is set to one. Three different READ operations
are possible: Immediate/Current Address READ,
Selective/Random READ and Sequential READ.
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