MCP9843 Datasheet, PDF (36/62 Pages) Microchip Technology – Memory Module Temperature Sensor w/ EEPROM for SPD

MCP9843/98243
5.3.2 PAGE WRITE
The write Address Byte, word address and the first data
byte are transmitted to the MCP98243 in the same way
as in a byte write. Instead of generating a Stop
condition, the master transmits up to 15 additional data
bytes to the MCP98243, which are temporarily stored
in the on-chip page buffer and will be written into the
memory after the master has transmitted a Stop
condition. Upon receipt of each word, the four lower
order address pointer bits are internally incremented by
one. The higher order four bits of the word address
remain constant. If the master should transmit more
than 16 bytes prior to generating the Stop condition, the
address counter will roll over and the previously
received data will be overwritten. As with the byte write
operation, once the Stop condition is received, an
internal write cycle will begin (Figure 5-14).
Note:
Page write operations are limited to writing
bytes within a single physical page,
regardless of the number of bytes actually
being written. Physical page boundaries
start at addresses that are integer
multiples of the page buffer size (or ‘page
size’) and end at addresses that are
integer multiples of [page size - 1]. If a
Page Write command attempts to write
across a physical page boundary, the
result is that the data wraps around to the
beginning of the current page (overwriting
data previously stored there), instead of
being written to the next page, as might be
expected. It is therefore necessary for the
application software to prevent page write
operations that would attempt to cross a
page boundary.
SCL
SDA
1 2 34 5678
1 23 4 56 7 8
S
1
0
1
0
A
2
A
1
A
0
W
A
C
K
X
X
X
X
X
X
XX
A
C
K
Address Byte
Word Address (n)
MCP98243
MCP98243
12345678
12345678
A
A
XX XXXXXX CXX XXXXXX CXX X
K
K
A
XXXC P
K
Data at (n)
Data at (n+1)
Data at (n+15)
MCP98243
MCP98243
MCP98243
Note: n is the initial address for a page.
FIGURE 5-14:
Timing Diagram for Page Write (See Section 4.0 “Serial Communication”).
DS22153C-page 36
© 2009 Microchip Technology Inc.