ds1876 Maxim Integrated Products, Inc., ds1876 Datasheet - Page 45

• Manufacturer Part Number: ds1876
• Description: Sfp Controller With Dual Ldd Interface
• Manufacturer: Maxim Integrated Products, Inc.

Table 02h, Register 80h: MODE (continued)
Table 02h, Register 81h: TEMPERATURE INDEX (TINDEX)
81h
FACTORY DEFAULT
READ ACCESS
WRITE ACCESS
A2h AND B2h MEMORY
MEMORY TYPE
Holds the calculated index based on the temperature measurement. This index is used for the address during lookup
of Tables 04h and 06h. Temperature measurements below -40NC or above +102NC are clamped to 80h and C7h,
respectively. The calculation of TINDEX is as follows:
For the temperature-indexed LUTs (2NC), the index used during the lookup function for each table is as follows:
Table 04h (MOD)
Table 06h (APC)
For the 8-position LUT tables, the following table shows the lookup function:
TINDEX
BYTE
TEMP (NC)
BIT 7
2
7
______________________________________________________________________________________
BIT 2
BIT 1
BIT 0
SFP Controller with Dual LDD Interface
1000_0xxx
< -8
F8
MOD1EN:
0 = MOD1 DAC is writable by the user and the LUT recalls are disabled. This allows the user to
interactively test their modules by writing the values for MOD1. The output is updated with the new
value at the end of the write cycle. The I
1 = (default) Enables automatic control of the LUT for MOD1 DAC.
QT1EN:
0 = QTs (HBIAS, TXP HI, TXP LO) for transmitter 1 are writable by the user and the LUT recalls are
disabled. This allows the user to interactively test their modules by writing to the QT thresholds.
The thresholds are updated with the new values at the end of the write cycle. The I
condition is the end of the write cycle.
1 = (default) Enables automatic control of the LUT QTs for transmitter 1.
APC1EN:
0 = APC1 DAC is writable by the user and the LUT recalls are disabled. This allows the user to
interactively test their modules by writing the values for APC1. The output is updated with the new
value at the end of the write cycle. The I
1 = (default) Enables automatic control of the LUT for APC1 DAC.
2
6
1
1
1001_0xxx
TINDEX
TINDEX
-8 to +8
F9
2
6
6
00h
PW2 or (PW1 and RWTBL2) or (PW1 and RTBL2)
(PW2 and AEN = 0) or (PW1 and RWTBL2 and AEN = 0)
Common A2h and B2h memory location
Volatile
5
1001_1xxx
+8 to +24
TINDEX
TINDEX
TINDEX
FA
5
5
=
2
4
Temp_Value 40 C
1010_0xxx
+24 to +40
TINDEX
TINDEX
FB
2
2
2 C
C STOP condition is the end of the write cycle.
C STOP condition is the end of the write cycle.
°
4
4
+
2
3
1010_1xxx
+40 to +56
TINDEX
TINDEX
°
FC
+
80h
3
3
2
1011_0xxx
+56 to +72
TINDEX
TINDEX
2
FD
2
2
1011_1xxx
+72 to +88
TINDEX
TINDEX
2
1
FE
2
C STOP
1
1
11xx_xxxx
TINDEX
TINDEX
BIT 0
R 88
2
FF
0
0
0
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