X9252_14 Datasheet, PDF (14/19 Pages) Intersil Corporation – Quad Digitally-Controlled Potentiometer

X9252
Page Write Operation
As stated previously, the memory is organized as a single
Status Register (SR), and four pages of four registers each.
Each page contains one Data Register for each DCP. The
order of the bytes within a page is DR0i, followed by DR1i,
followed by DR2i, and then DR3i, with i being the Data
Register number (0, 1, 2, or 3). Normally a page write
operation will be used to efficiently update all four data
registers and WCR in a single write command, starting at
DCP0 and finishing with DCP3.
In order to perform a Page Write operation to the memory
array, the NVEnable bit in the SR must first be set to “1”.
A Page Write operation is initiated in the same manner as
the byte write operation; but instead of terminating the write
cycle after the first data byte is transferred, the master can
transmit up to 4 bytes (see Figure 8). After the receipt of
each byte, the X9252 responds with an ACK, and the
internal DCP address counter is incremented by one. The
page address remains constant. When the counter reaches
the end of the page (DR3i, 03hex), it “rolls over” and goes
back to the first byte of the same page (DR0i, 00hex).
For example, if the master writes 3 bytes to a page starting
at location DR22, the first 2 bytes are written to locations
DR22 and DR32, while the last byte is written to locations
DR02. Afterwards, the DCP counter would point to location
DR12. If the master supplies more than 4 bytes of data, then
new data overwrites the previous data, one byte at a time.
The master terminates the loading of Data Bytes by issuing
a STOP condition, which initiates the nonvolatile write cycle.
As with the Byte Write operation, all inputs are disabled until
completion of the internal write cycle. If the WP pin is low,
the nonvolatile write cycle doesn’t start and the bytes are
discarded.
Notice that the Data Bytes are also written to the WCR of the
corresponding DCPs, therefore in the above example,
WCR2, WCR3, and WCR0 are also written and WCR1 is
updated with the contents of DR12.
SIGNALS FROM
THE MASTER
SIGNAL AT SDA
SIGNALS FROM
THE SLAVE
WRITE
S
T
A
SLAVE
R
ADDRESS
T
ADDRESS
BYTE
2<n<4
DATA BYTE (1)
S
T
DATA BYTE (n)
O
P
01 01
0
A
A
C
C
K
K
A
A
C
C
K
K
FIGURE 8. PAGE WRITE OPERATION
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FN8167.3
July 24, 2014