X40420/X40421 – Preliminary
Figure 10. Byte Write Sequence
S
t
a
r
t
S
t
o
p
Signals from
the Master
Slave
Address
Byte
Address
Data
SDA Bus
Signals from
the Slave
0
A
C
K
A
C
K
A
C
K
Figure 11. Page Write Operation
S
t
a
r
t
M
The device is capable of a page write operation. It is
initiated in the same manner as the byte write opera-
tion; but instead of terminating the write cycle after the
first data byte is transferred, the master can transmit
an unlimited number of 8-bit bytes. After the receipt of
each byte, the device will respond with an acknowl-
edge, and the address is internally incremented by
one. The page address remains constant. When the
counter reaches the end of the page, it “rolls over” and
goes back to ‘0’ on the same page.
IN
A
Data
(1)
A
C
K
address
10
EL
I
R
A
C
K
Page Write
This means that the master can write 16 bytes to the
page starting at any location on that page. If the mas-
ter begins writing at location 10, and loads 12 bytes,
then the first 6 bytes are written to locations 10 through
15, and the last 6 bytes are written to locations 0
through 5. Afterwards, the address counter would point
to location 6 of the page that was just written. If the
master supplies more than 16 bytes of data, then new
data over-writes the previous data, one byte at a time.
Y
(1
≤
n
≤
16)
6 Bytes
Signals from
the Master
SDA Bus
Signals from
the Slave
Slave
Address
Byte
Address
Data
(n)
S
t
o
p
1 0 1
0 0
0
Figure 12. Writing 12 bytes to a 16-byte page starting at location 10.
PR
A
C
K
A
C
K
6 Bytes
address pointer
ends here
Addr = 6
address
=5
address
n-1
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. See Figure 11 for the address, acknowl-
edge, and data transfer sequence.
REV 1.2.14 7/12/02
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Characteristics subject to change without notice.
11 of 25
XICOR [ XICOR INC. ]
