AN-2030: Digital Diagnostic Monitoring Interface for Optical Transceivers Finisar 1 Application Note AN-2030 2 Digital Diagnostic Monitoring Interface for SFP Optical Transceivers 3 4 5 6 7 1. Scope and Overview 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 This document defines an enhanced digital diagnostic monitoring interface available in Finisar SFP and GBIC optical transceivers.
AN-2030: Digital Diagnostic Monitoring Interface for Optical Transceivers Finisar 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 3. Enhanced Digital Diagnostic Interface Definition Overview The enhanced digital diagnostic interface is a superset of the MOD-DEF interface defined in the SFP MSA document dated September 14, 2000. The 2-wire interface pin definitions, hardware, and timing are clearly defined there, as well as in Section 4 below.
AN-2030: Digital Diagnostic Monitoring Interface for Optical Transceivers 1 2 3 4 5 6 Figure 3.
AN-2030: Digital Diagnostic Monitoring Interface for Optical Transceivers Finisar Table 3.1 Serial ID: Data Fields – Address A0 1 Size Data (Bytes) Address 0 1 1 1 Name of Field Identifier Ext. Identifier Description of Field BASE ID FIELDS Type of serial transceiver (see table 3.
AN-2030: Digital Diagnostic Monitoring Interface for Optical Transceivers Finisar 1 Identifier 2 The identifier value specifies the physical device described by the serial information. This value shall be included in the serial data. The defined identifier values are shown in table 3.2. Finisar SFP modules have this byte set to 03h. Finisar GBIC modules have this byte set to 01h. 3 4 5 TABLE 3.
AN-2030: Digital Diagnostic Monitoring Interface for Optical Transceivers Finisar 1 TABLE 3.
AN-2030: Digital Diagnostic Monitoring Interface for Optical Transceivers Finisar 1 Transceiver 2 The following bit significant indicators define the electronic or optical interfaces that are supported by the transceiver. At least one bit shall be set in this field. For Fibre Channel transceivers, the Fibre Channel speed, transmission media, transmitter technology, and distance capability shall all be indicated. The SONET Compliance Codes are described in more detail in table 3.4a. 3 4 5 6 Table 3.
Finisar AN-2030: Digital Diagnostic Monitoring Interface for Optical Transceivers 9 10 The SONET compliance code bits allow the host to determine with which specifications a SONET transceiver complies. For each bit rate defined in Table 3.5 (OC-3, OC-12, OC-48), SONET specifies short reach (SR), intermediate reach (IR), and long reach (LR) requirements. For each of the three bit rates, a single short reach (SR) specification is defined.
AN-2030: Digital Diagnostic Monitoring Interface for Optical Transceivers Finisar 1 BR, nominal 2 The nominal bit rate (BR, nominal) is specified in units of 100 Megabits per second, rounded off to the nearest 100 Megabits per second. The bit rate includes those bits necessary to encode and delimit the signal as well as those bits carrying data information. A value of 0 indicates that the bit rate is not specified and must be determined from the transceiver technology.
AN-2030: Digital Diagnostic Monitoring Interface for Optical Transceivers 1 2 Finisar transceiver technology. It is common for the transceiver to support both 50 micron and 62.5 micron fiber. 3 4 Length (Copper) 5 This value specifies the minimum link length that is supported by the transceiver while operating in compliance with the applicable standards using copper cable. The value is in units of 1 meter. A value of 255 means that the transceiver supports a link length greater than 254 meters.
AN-2030: Digital Diagnostic Monitoring Interface for Optical Transceivers Finisar 1 Vendor Rev 2 The vendor revision number (vendor rev) is a 4-byte field that contains ASCII characters, left-aligned and padded on the right with ASCII spaces (20h), defining the vendor’s product revision number. A value of all zero in the 4-byte field indicates that the vendor rev is unspecified.
AN-2030: Digital Diagnostic Monitoring Interface for Optical Transceivers Finisar 1 Options 2 The bits in the option field shall specify the options implemented in the transceiver as described in table 3.6. StandardFinisar SFP transceivers do not implement TX_FAULT or RATE_SELECT, so byte 65 set to 00010010b. 3 4 5 Table 3.6: Option values 6 Data Bit Description of option Address 64 7-0 Reserved 65 7-6 Reserved 65 5 Indicates if RATE_SELECT is implemented.
AN-2030: Digital Diagnostic Monitoring Interface for Optical Transceivers Finisar 1 2 Date Code 3 4 5 The date code is an 8-byte field that contains the vendor’s date code in ASCII characters. The date code is mandatory. The date code shall be in the format specified by table 3.7. 6 Table 3.7: Date Code 7 Data Description of field Address 84-85 86-87 ASCII code, two low order digits of year. (00 = 2000).
Finisar AN-2030: Digital Diagnostic Monitoring Interface for Optical Transceivers Table 3.8: Diagnostic Monitoring Type 1 Data Address Bits 92 7 Description Reserved for legacy diagnostic implementations. Must be ‘0’ for compilance with this document. 92 6 Digital diagnostic monitoring implemented (described in this document). Must be ‘1’ for compliance with this document.
AN-2030: Digital Diagnostic Monitoring Interface for Optical Transceivers Finisar 1 Enhanced Options 2 10 11 “Enhanced Options” is a 1 byte field with 8 single bit indicators which describe the optional digital diagnostic features implemented in the transceiver. Since transceivers will not necessarily implement all optional features described in this document, the “Enhanced Options” bit field allows the host system to determine which functions are available over the 2 wire serial bus.
AN-2030: Digital Diagnostic Monitoring Interface for Optical Transceivers Finisar 1 Table 3.
AN-2030: Digital Diagnostic Monitoring Interface for Optical Transceivers Finisar 1 2 Diagnostics 3 4 5 2 wire serial bus address 1010001X (A2h) is used to access measurements of transceiver temperature, internally measured supply voltage, TX bias current, TX output power, received optical power, and two additional quantities to be defined in the future. 6 7 8 9 10 The values are interpreted differently depending upon the option bits set at address 92.
Finisar AN-2030: Digital Diagnostic Monitoring Interface for Optical Transceivers 1 2 calibrated to absolute units using the most representative fiber output type. Accuracy is ±3dB. Data is not valid when the transmitter is disabled. 3 4 5 6 7 8 5) Measured RX received average optical power in mW. Represented as a 16 bit unsigned integer with the power defined as the full 16 bit value (0 – 65535) with LSB equal to 0.1 µW, yielding a total range of 0 to 6.5535 mW (~ -40 to +8.2 dBm).
AN-2030: Digital Diagnostic Monitoring Interface for Optical Transceivers Finisar 1 External Calibration 2 3 4 5 6 Measurements are raw A/D values and must be converted to real units using calibration constants stored in EEPROM locations 56 – 95 at 2 wire serial bus address A2h (see Table 3.15). Calibration is valid over specified device operating temperature and voltage. Alarm and warning threshold values should be interpreted in the same manner as real time 16 bit data.
Finisar AN-2030: Digital Diagnostic Monitoring Interface for Optical Transceivers 1 2 5) Measured received optical power. Received power, RX_PWR, is given in µW by the following equation: 3 4 5 Rx_PWR (µW) = Rx_PWR(4) * Rx_PWRAD4 (16 bit unsigned integer) + Rx_PWR(3)*Rx_PWRAD3 (16 bit unsigned integer) + Rx_PWR(2)*Rx_PWRAD2 (16 bit unsigned integer) + Rx_PWR(1) *Rx_PWRAD (16 bit unsigned integer) + Rx_PWR(0) 6 7 8 9 10 The result is in units of 0.1µW yielding a total range of 0 – 6.5mW. See Table 3.
AN-2030: Digital Diagnostic Monitoring Interface for Optical Transceivers 1 2 3 4 5 Finisar Calibration Constants TABLE 3.15: Calibration constants for External Calibration Option (2 Wire Address A2h) Address # Bytes Name Description 56-59 4 Rx_PWR(4) Single precision floating point calibration data - Rx optical power. Bit 7 of byte 56 is MSB. Bit 0 of byte 59 is LSB. Rx_PWR(4) is set to zero for “internally calibrated” devices.
Finisar AN-2030: Digital Diagnostic Monitoring Interface for Optical Transceivers 1 2 3 4 5 6 7 8 9 10 11 12 The slope constants at addresses 76, 80,84, and 88, are unsigned fixed-point binary numbers. The slope will therefore always be positive. The binary point is in between the upper and lower bytes, i.e., between the eight and ninth most significant bits. The most significant byte is the integer portion in the range 0 to +255.
Finisar AN-2030: Digital Diagnostic Monitoring Interface for Optical Transceivers 1 2 Table 3.16c: IEEE-754 Single-Precision Floating Point Number Format SIGN FUNCTION BIT 31 BYTE ß Most Significant 3 4 5 6 7 8 9 10 11 EXPONENT MANTISSA 30……………………23 3 22……………………………………………………………0 2 1 0 Least Significant à Rx_PWR(4), as an example, is stored as in Table 3.16d. Table 3.
AN-2030: Digital Diagnostic Monitoring Interface for Optical Transceivers Finisar Real Time Diagnostic Registers TABLE 3.17: A/D Values and Status Bits (2 Wire Address A2h) Byte Bit Name Description Converted analog values. Calibrated 16 bit data. 96 All Temperature MSB 97 All Temperature LSB 98 All Vcc MSB Internally measured module temperature. Internally measured supply voltage in transceiver.
AN-2030: Digital Diagnostic Monitoring Interface for Optical Transceivers Finisar 110 1 LOS Digital state of the LOS Output Pin. Updated within 100msec of change on pin. This function is implemented in all Finisar transceivers with digital diagnostic capability. 110 0 Data_Ready_Bar Indicates transceiver has achieved power up and data is ready. Bit remains high until data is ready to be read at which time the device sets the bit low.
AN-2030: Digital Diagnostic Monitoring Interface for Optical Transceivers Finisar Table 3.18: Alarm and Warning Flag Bits (2-Wire Address A2h) Reserved Optional Alarm and Warning Flag Bits 112 7 Temp High Alarm Set when internal temperature exceeds high alarm level. 112 6 Temp Low Alarm Set when internal temperature is below low alarm level. 112 5 Vcc High Alarm Set when internal supply voltage exceeds high alarm level.
AN-2030: Digital Diagnostic Monitoring Interface for Optical Transceivers Finisar Bytes 123 – 126 contain write-only RAM for entry of a 32 bit password that allows access to user writable EEPROM at locations 128-247. The default password for Finisar devices is 0, however it can be set to any value at the factory to insure security of the user writable EEPROM contents. Please contact your Finisar sales representative for details on setting up a custom password.
AN-2030: Digital Diagnostic Monitoring Interface for Optical Transceivers 4. Finisar DDTC Electrical Interface Definition Overview The Digital Diagnostics Transceiver Controller (DDTC) IC manages all system monitoring functions in the SFP transceiver module. The DDTC is accessed through a 2-wire serial interface, utilizing the serial ID pins defined by the SFP MSA: § SFP Pin 4 – MOD_DEF(2): Serial Data interface (SDA). The serial data pin is for serial data transfer to and from the DDTC.
AN-2030: Digital Diagnostic Monitoring Interface for Optical Transceivers Finisar 2-Wire Interface Reset: After any interruption in protocol, power loss, or system reset, the following steps reset the DDTC. 1. Clock up to nine cycles. 2. Look for SDA high in each cycle while SCL is high. 3. Create a Start Condition while SDA is high. Device Addressing: The DDTC must receive an 8-bit device address word following a start condition to enable a specific device for a read or write operation.
AN-2030: Digital Diagnostic Monitoring Interface for Optical Transceivers Finisar Acknowledge Polling: Once the internally-timed write has started and the DDTC inputs are disabled, acknowledge polling can be initiated. The process involves transmitting a start condition followed by the device address. The R/W bit signifies the type of operation that is desired. The read or write sequence will only be allowed to proceed if the internal write cycle has completed and the DDTC responds with a zero.
AN-2030: Digital Diagnostic Monitoring Interface for Optical Transceivers Finisar Detailed 2-Wire Serial Port Operation This section gives a more detailed description of 2-wire theory of operation. The 2-wire serial port interface supports a bi-directional data transmission protocol with device addressing. A device that sends data on the bus is defined as a transmitter, and a device receiving data as a receiver. The device that controls the message is called a “master.
AN-2030: Digital Diagnostic Monitoring Interface for Optical Transceivers Finisar Within the bus specifications a regular mode (100 kHz clock rate) and a fast mode (400 kHz clock rate) are defined. The DDTC works in both modes. 5) Acknowledge: Each receiving device, when addressed, is obliged to generate an Acknowledge after the reception of each byte. The master device must generate an extra clock pulse which is associated with this acknowledge bit.
AN-2030: Digital Diagnostic Monitoring Interface for Optical Transceivers Finisar of the command/control byte (R/W) defines the operation to be performed. When set to a 1 a read operation is selected, and when set to a 0 a write operation is selected. Following the START condition, the DDTC monitors the SDA bus checking the device type identifier being transmitted. Upon receiving the chip address control code, and the read/write bit, the slave device outputs an acknowledge signal on the SDA line.
Finisar AN-2030: Digital Diagnostic Monitoring Interface for Optical Transceivers DC ELECTRICAL CHARACTERISTICS PARAMETER SYMBOL CONDITION ( Vcc = 3.15V to 3.60V) MIN TYP MAX UNITS NOTES ILI -1 +1 µA 2 Input Logic 1 (SDA, SCL) VIH 0.7Vcc Vcc+0.5 V 1 Input Logic 0 (SDA, SCL) VIL GND-0.5 0.3Vcc V 1 Low Level Output Current (SDA) IOL1 0.4V 3 mA 1 IOL2 0.
AN-2030: Digital Diagnostic Monitoring Interface for Optical Transceivers Finisar For More Information Finisar Corporation 1308 Moffett Park Drive Sunnyvale, CA 94089-1133 Tel. (408) 548-1000 Fax (408) 541-6138 sales@finisar.com www.finisar.
