X4163-65 Datasheet, PDF (11/22 Pages) Intersil Corporation – Selectable watchdog timer

X4163, X4165
Figure 8. Byte Write Sequence
Signals from
the Master
SDA Bus
Signals from
the Slave
S
t
a
Slave
r Address
t
Word Address
Byte 1
Word Address
Byte 0
Data
S
t
o
p
10 1 0
0
A
A
A
A
C
C
C
C
K
K
K
K
Serial Write Operations
BYTE WRITE
For a write operation, the device requires the Slave
Address Byte and a Word Address Byte. This gives
the master access to any one of the words in the
array. After receipt of the Word Address Byte, the
device responds with an acknowledge, and awaits
the next eight bits of data. After receiving the 8 bits of
the Data Byte, the device again responds with an
acknowledge. The master then terminates the trans-
fer by generating a stop condition, at which time the
device begins the internal write cycle to the nonvola-
tile memory. During this internal write cycle, the
device inputs are disabled, so the device will not
respond to any requests from the master. The SDA
output is at high impedance. See Figure 8.
A write to a protected block of memory will suppress
the acknowledge bit.
Page Write
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. This means that
the master can write 64 bytes to the page starting at
any location on that page. If the master begins writing
at location 60, and loads 12-bytes, then the first 4-
bytes are written to locations 60 through 63, and the
last 8-bytes are written to locations 0 through 7. After-
wards, the address counter would point to location 8 of
the page that was just written. If the master supplies
more than 64-bytes of data, then new data over-writes
the previous data, one byte at a time.
Figure 9. Page Write Operation
S
Signals from ^t
the Master
a
r
t
Slave
Address
Word Address
Byte 1
Word Address
Byte 0
(1 < n < 64)
Data
(1)
S
Data
t
(n)
o
p
SDA Bus
10 10
0
Signals from
the Slave
A
A
A
A
A
C
C
C
C
C
K
K
K
K
K
11
FN8120.2
November 26, 2007