Finisar Understanding Digital Diagnostic Monitoring in the Application Note AN-2030

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AN-2030: Digital Diagnostic Monitoring Interface for Optical Transceivers

F i n i s a r

1

2Table 3.16c: IEEE-754 Single-Precision Floating Point Number Format

FUNCTION	SIGN	EXPONENT				MANTISSA
BIT	31	30……………………23		22……………………………………………………………0
BYTE		3		2	1		0
ß Most Significant							Least Significantà

3

4

5

6

7

8

9

10

11

Rx_PWR(4), as an example, is stored as in Table 3.16d.

Table 3.16d: Example of Floating Point Representation

BYTE	CONTENTS	SIGNIFICANCE
ADDRESS
56	SEEEEEEE	Most
57	EMMMMMMM	2nd Most
58	MMMMMMMM	2nd Least
59	MMMMMMMM	Least

12

13

14where S = sign bit; E = exponent bit; M = mantissa bit.

15

16Special cases of the various bit values are reserved to represent indeterminate values

17such as positive and negative infinity; zero; and “NaN”or not a number. NaN indicates

18an invalid result. As of this writing, explanations of the IEEE single precision floating

19point format were posted on the worldwide web at

20

21http://www.psc.edu/general/software/packages/ieee/ieee.html

22

23and

24

25http://research.microsoft.com/~hollasch/cgindex/coding/ieeefloat.html.

26

27 The actual IEEE standard is available at www.IEEE.org.

9/26/02 Revision D

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Contents 35 2. Applicable Documents Scope and OverviewEnhanced Digital Diagnostic Interface Definition Overview Control Functions 8 bytes Password Entry 8 bytesSpecific Data Field Descriptions Cal Constants BytesName Bytes Description of Field Address Serial ID Data Fields Address A0Data Extended Identifier ConnectorIdentifier Identifier valuesDescription of connector Connector valuesTransceiver codes TransceiverCode Description of encoding mechanism 4a Sonet Reach SpecifiersEncoding Speed Reach Specifier bit DescriptionLength 50μ BR, nominalLength 9μ-km Length 9μVendor OUI Length CopperVendor name Dwdm Channel SpacingDwdm Wavelength Fraction Vendor RevLaser Wavelength 13 BR, min OptionsOption values BR, maxData Description of field Address Diagnostic Monitoring TypeDate Code N i s a r Enhanced Options 11 SFF-8472 Compliance 10 I/O Timing for Soft Control & Status FunctionsSFF-8472 Compliance Diagnostics 13 Digital temperature format Temperature 12 Bit weights C for temperature reporting registersN i s a r 14 Alarm and Warning Thresholds 2-Wire Address A2h Alarm and Warning ThresholdsN i s a r 16b Format for offsets 16a Unsigned fixed-point binary format for slopes16d Example of Floating Point Representation 16c IEEE-754 Single-Precision Floating Point Number FormatBit Name Description LOS Alarm and Warning Flags18 Alarm and Warning Flag Bits 2-Wire Address A2h Address # Bytes Name Description 19 Password Addresses 2-Wire Address A2h20 User Eeprom 2-Wire Address A2h Byte Bit Name DescriptionDdtc Electrical Interface Definition Overview Wire Interface OperationN i s a r Current Address Read Detailed 2 -Wire Serial Port Operation N i s a r Wire Protocol Data Transfer Protocol Vcc = 3.15V to DC Electrical CharacteristicsFor More Information