X9530 Datasheet, PDF (18/30 Pages) Xicor Inc. – Temperature Compensated Laser Diode Controller

X9530
Figure 17. Example: Writing 12 bytes to a 16-byte page starting at location 11.
7 bytes
Address=0
Address=6
5 b5ybtyetess
Address=11
Address=7
Address Pointer
Ends Up Here
Address=15
condition. The first data byte is written to location 81h,
the second to 82h, the third to 83h, and the last one to
84h.
The four registers Control 1 through 4, have a
nonvolatile and a volatile cell for each bit. At power up,
the content of the nonvolatile cells is automatically
recalled and written to the volatile cells. The content of
the volatile cells controls the X9530’s functionality. If bit
NV1234 in the Control 0 register is set to “1”, a Write
operation to these registers writes to both the volatile
and nonvolatile cells. If bit NV1234 in the Control 0
register is set to “0”, a Write operation to these
registers only writes to the volatile cells. In both cases
the newly written values effectively control the X9530,
but in the second case, those values are lost when the
part is powered down.
If bit NV1234 is set to “0”, a Byte Write operation to
Control registers 0 or 5 causes the value in the
nonvolatile cells of Control registers 1 through 4 to be
recalled into their corresponding volatile cells, as
during power up. This doesn’t happen when the WP
pin is LOW, because Write Protection is enabled. It is
generally recommended to configure Control registers
0 and 5 before writing to Control registers 1 through 4.
When reading any of the control registers 1, 2, 3, or 4,
the Data Bytes are always the content of the
corresponding nonvolatile cells, even if bit NV1234 is
"0" (See “Control and Status Register Format”).
Read Operation
A Read operation consist of a three byte instruction
followed by one or more Data Bytes (See Figure 19).
The master initiates the operation issuing the following
sequence: a START, the Slave Address byte with the
R/W bit set to “0”, an Address Byte, a second START,
and a second Slave Address byte with the R/W bit set
to “1”. After each of the three bytes, the X9530
responds with an ACK. Then the X9530 transmits Data
Bytes as long as the master responds with an ACK
during the SCL cycle following the eigth bit of each
byte. The master terminates the read operation
(issuing a STOP condition) following the last bit of the
last Data Byte (See Figure 19).
The Data Bytes are from the memory location indicated
by an internal pointer. This pointer initial value is
determined by the Address Byte in the Read operation
instruction, and increments by one during transmission of
Figure 18. Writing to Control Registers 1, 2, 3, and 4
Signals from
the Master
Signal at SDA
Signals from
the Slave
S
Write
t
a
Slave
r
Address
Address
Byte = 81h
t
Four Data Bytes
Data Byte for
Control 1
S
Data Byte for
t
Control 4
o
p
10 10
0 10 00 0 0 01
A
A
C
C
K
K
A
A
C
C
K
K
REV 3.7 8/26/04
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Characteristics subject to change without notice. 18 of 30