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
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
23accuracy of ± 3°C. The temperature sensor is located in the center of the module
24 | 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
33laser bias current readings.
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:
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 (~
9/26/02 Revision D | Page 17 |
