X24256
Characteristics subject to change without notice.
6 of 18
If the master writes more than 64 bytes, then the previ-
ously loaded data is overwritten by the new data, one
byte at a time.
The master terminates the data byte loading by issuing
a stop condition, which causes the device to begin the
nonvolatile write cycle. As with the byte write operation,
all inputs are disabled until completion of the internal
write cycle. Refer to Figure 6 for the address, acknowl-
edge, and data transfer sequence.
Figure 5. Byte Write Sequence
Figure 6. Page Write Sequence
SIGNALS
FROMTHE
MASTER
SDA BUS
SIGNALS
FROMTHE
SLAVE
S
T
A
R
T
S
SLAVE
ADDRESS
S
T
O
P
A
C
K
A
C
K
A
C
K
A
C
K
WORDADDRESS
BYTE 1
DATA
1 0 1 0
WORD ADDRESS
BYTE 0
P
0
0
S
T
A
R
T
SLAVE
ADDRESS
S
T
O
P
P
A
C
K
A
C
K
A
C
K
A
C
K
A
C
K
DATA
(0)
SIGNALS
FROMTHE
MASTER
SDA BUS
SIGNALS
FROMTHE
SLAVE
(n)
WORD ADDRESS
BYTE 1
WORDADDRESS
BYTE 0
0
S
DATA
1 0 1 0
(0
≤
n
≤
64)
0
Stop and Write Modes
Stop conditions that terminate write operations must
be sent by the master after sending at least 1 full data
byte and it’s associated ACK signal. If a stop is issued
in the middle of a data byte, or before 1 full data byte +
ACK is sent, then the device will reset itself without
performing the write. The contents of the array will not
be affected.
Acknowledge Polling
The maximum write cycle time can be significantly
reduced using Acknowledge Polling. To initiate
Acknowledge Polling, the master issues a start condi-
tion followed by the Slave Address Byte for a write or
read operation. If the device is still busy with the inter-
nal write cycle, then no ACK will be returned. If the
device has completed the internal write operation, an
ACK will be returned and the host can then proceed
with the read or write operation. Refer to Figure 7.
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