Finisar AN-2030 specifications Diagnostics

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AN-2030: Digital Diagnostic Monitoring Interface for Optical Transceivers

1

F i n i s a r

2Diagnostics

3 2 wire serial bus address 1010001X (A2h) is used to access measurements of

4transceiver temperature, internally measured supply voltage, TX bias current, TX output

5power, received optical power, and two additional quantities to be defined in the future.

6The values are interpreted differently depending upon the option bits set at address 92.

7If bit 5 “internally calibrated” is set, the values are calibrated absolute measurements,

8which should be interpreted according to the section “Internal Calibration” below. If bit 4

9“externally calibrated” is set, the values are A/D counts, which are converted into real

10units per the subsequent section titled “External Calibration”.

11Measured parameters are reported in 16 bit data fields, i.e., two concatenated bytes.

12To guarantee coherency of the diagnostic monitoring data, the host is required to

13retrieve any multi-byte fields from the diagnostic monitoring data structure (IE: Rx Power

14MSB - byte 104 in A2h, Rx Power LSB - byte 105 in A2h) by the use of a single two-

15byte read sequence across the serial interface.

16Measurements are calibrated over specified device operating temperature and voltage

17and should be interpreted as defined below. Alarm and warning threshold values

18should be interpreted in the same manner as real time 16 bit data.

19Internal Calibration

201) Internally measured transceiver temperature. Represented as a 16 bit signed twos

21complement value in increments of 1/256 degrees Celsius, yielding a total range of –

22128°C to +128°C. Temperature measurement is valid from –40°C to +125°C with an

23accuracy of ± 3°C. The temperature sensor is located in the center of the module

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and is typically 5 to 10 degrees ho tter than the module case. See Tables 3.12 and

253.13 below for examples of temperature format.

262) Internally measured transceiver supply voltage. Represented as a 16 bit unsigned

27integer with the voltage defined as the full 16 bit value (0 – 65535) with LSB equal to

28100 µVolt, yielding a total range of 0 to +6.55 Volts. Accuracy is ±100mV.

293) Measured TX bias current in µA. Represented as a 16 bit unsigned integer with the

30current defined as the full 16 bit value (0 – 65535) with LSB equal to 2 µA, yielding a

31total range of 0 to 131 mA. Accuracy is ± 10%. Early versions of the digital

32diagnostic standard (SFF-8472) used a scale factor of 1µA/AD Count for interpreting

33laser bias current readings. SFF-8472 later changed the scale factor to the current

34value of 2µA/AD Count. All Finisar modules using a scale factor of 2µA/AD Count

35have an ASCII “A” written in byte 56 of the ‘vendor rev’ field (see table 3.1). Legacy

36Finisar modules using a scale factor of 1µA/AD Count contain either zero or ASCII

37space (20h) or one of two place holders: “X1—“, “1A—“, in location 56.

384) Measured TX output power in mW. Represented as a 16 bit unsigned integer with

39the power defined as the full 16 bit value (0 – 65535) with LSB equal to 0.1 µW,

40yielding a total range of 0 to 6.5535 mW (~ -40 to +8.2 dBm). Data is factory

9/26/02 Revision D

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Contents 35 2. Applicable Documents Scope and OverviewEnhanced Digital Diagnostic Interface Definition Overview Specific Data Field Descriptions Password Entry 8 bytesCal Constants Bytes Control Functions 8 bytesName Bytes Description of Field Address Serial ID Data Fields Address A0Data Identifier ConnectorIdentifier values Extended IdentifierDescription of connector Connector valuesTransceiver codes TransceiverEncoding 4a Sonet Reach SpecifiersSpeed Reach Specifier bit Description Code Description of encoding mechanismLength 9μ-km BR, nominalLength 9μ Length 50μVendor name Length CopperDwdm Channel Spacing Vendor OUIDwdm Wavelength Fraction Vendor RevLaser Wavelength Option values OptionsBR, max 13 BR, minData 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 20 User Eeprom 2-Wire Address A2h 19 Password Addresses 2-Wire Address A2hByte Bit Name Description Address # Bytes 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
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