XRT91L82IB

xr XRT91L82 PRELIMINARY 2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER APRIL 2005 REV. P1.0.5 GENERAL DESCRIPTION of the FIFO_AUTORST register bit can automatically recover from an overflow condition. The operation of the device can be monitored by checking the status of the LOCKDET_CMU and LOCKDET_CDR output signals. An on-chip phase/frequency detector and charge-pump offers the ability to form a de-jittering PLL with an external VCXO that can be used in loop timing mode to clean up the recovered clock in the receive section. The XRT91L82 is a fully integrated SONET/SDH transceiver for OC-48/STM16 applications supporting the use of Forward Error Correction (FEC) capability. The transceiver includes an on-chip Clock Multiplier Unit (CMU), which uses a high frequency PhaseLocked Loop (PLL) to generate the high-speed transmit serial clock from slower external clock references. It also provides Clock and Data Recovery (CDR) functions by synchronizing its on-chip Voltage Controlled Oscillator (VCO) to the incoming serial data stream. The chip provides serial-to-parallel and parallel-to-serial converters and 16-bit Differential LVDS/LVPECL, or Single-Ended LVPECL system interfaces in both receive and transmit directions. The transmit section includes a 16x9 Elastic Buffer (FIFO) to absorb any phase differences between the transmitter clock input and the internally generated transmitter reference clock. In the event of an overflow, an internal FIFO control circuit outputs an OVERFLOW indication. The FIFO under the control APPLICATIONS • SONET/SDH-based Transmission Systems • Add/Drop Multiplexers • Cross Connect Equipment • ATM and Multi-Service Switches, Routers and Switch/Routers • DSLAMS • SONET/SDH Test Equipment • DWDM Termination Equipment FIGURE 1. BLOCK DIAGRAM OF XRT91L82 STS-48 TRANSCEIVER OVERFLOW WP TXOP/N 16x9 FIFO FIFO_RST TXDI[15:0]P/N 16 PISO (Parallel Input Serial Output) Re-Timer TXSCLKOP/N RP TXPCLKIP/N Div by 16 TXPCLKOP/N TXCLKO16P/N TXCLKO16SEL CMU DLOOP RLOOPP RLOOPS SIPO (Serial Input Parallel Output) RXDO[15:0]P/N CDR RXIP/N 16 Div by 16 RXPCLKOP/N DISRD DISRDCLK RXCAP1P RXCAP1N/CPOUT INTERM/VCXO_IN LOCKDET_CDR LOCKDET_CMU XRES1N XRES1P SDEXT POLARITY PRBS_EN PRBS_ERR SE_REF SEREF_DIS CDRLCKREF TXSWING TXSCLKOOFF PIO_CFG [1:0] REF1CLKP/N REF2CLKP/N REFREQSEL1 REFREQSEL0 PFD & Charge Pump Hardware Control RLOOPS_PRBSCLR DLOOP LPTIME_NOJA Serial Microprocessor CS SCLK SDI SDO HOST/HW JTAG INT RESET TDO TDI TCK TMS TRST Exar Corporation 48720 Kato Road, Fremont CA, 94538 • (510) 668-7000 • FAX (510) 668-7017 • www.exar.com xr XRT91L82 PRELIMINARY 2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER REV. P1.0.5 FEATURES • 2.488 / 2.666 Gbps Transceiver • Targeted for SONET OC-48/SDH STM-16 Applications • Selectable full duplex operation between standard rate of 2.488 Gbps or Forward Error Correction rate of 2.666 Gbps • Single-chip fully integrated solution containing parallel-to-serial converter, clock multiplier unit (CMU), serialto-parallel converter, and clock data recovery (CDR) functions • 16-bit Differential LVDS/LVPECL, or Single-Ended LVPECL signaling data paths running at 155.52/166.63 Mbps using internal input termination for reduced passive components on board • Non-FEC and FEC rate REF1CLKP/N and REF2CLKP/N dual reference input ports • Supports 155.52/166.63MHz or 77.76/83.31MHz transmit and receive external reference input ports • Optional VCXO input port support multiple de-jittering modes in Host mode • On-chip phase detector and charge pump for external VCXO based de-jittering PLL • Internal FIFO decouples transmit parallel clock input and transmit parallel clock output • Provides Local, Remote Serial and Remote Parallel Loopback modes as well as Loop Timing mode • Diagnostics features include various lock detect functions and transmit CMU and receive CDR Lock Detect • Host mode serial microprocessor interface simplifies monitor and control • Meets Telcordia, ANSI and ITU-T jitter requirements including T1.105.03 - 2002 SONET Jitter Tolerance specification, GR-253 CORE, GR-253-ILR- SONET Jitter specifications. • Operates at 1.8V CMOS and CML Power with 3.3V I/O • 500mW Typical Power Dissipation using LVDS Interface • Package: 15 x 15 mm 196-pin STBGA • IEEE 1149.1 Compatable JTAG port PRODUCT ORDERING INFORMATION PRODUCT NUMBER PACKAGE TYPE OPERATING TEMPERATURE RANGE XRT91L82IB 196 STBGA -40°C to +85°C 2 RXIP RXIN VDD_CML TXON TXOP VDD_CML TXSCLKON TXSCLKOP B GND GND VDD_CML GND VDD_CML GND VDD_CML GND TCK TDI VDD_CML VDD_CML REF2CLKP VDD_CML REF1CLKP GND GND REF2CLKN GND REF1CLKN GND TXSCLKOOFF LOOPTM_NOJA C AVDD_RX SDEXT SEREFDIS TXCLKO16SEL LOCKDET_CDR LOCKDET_CMU VDD_CML CDRLCKREF VDD_CML AVDD_TX / CS DISRD D GND TXSWING FIFO_RST AVDD_RX PIO_CFG1 OVERFLOW TDO TMS / INT INTERM GND PRBS_ERR RESET PIO_CFG0 VDD_CMOS GND VDD_CMOS / VCXO_IN DISRDCLK REFREQSEL1 AVDD_TX GND REFREQSEL0 GND XRES1P PRBS_EN /PRBS_LOCK E RXCAP1P / SDI (I2C - SDA) / SCLK DLOOP POLARITY / SDO (I2C RXCAP1N - SCL) VDD_CMOS GND VDD_CMOS GND VDD_CMOS GND VDD_CMOS GND RLOOPS_PRBSCLR TXDI14P GND XRES1N AVDD_RX VDD_IO RXDO0N RXDO0P GND TXDI15N TXDI15P VDD_IO TXDI13N TXDI13P TXDI14N AVDD_TX GND GND RXDO1N RXDO1P GND RXDO2N RXDO2P RXDO3P TXDI11P GND TXDI12N TXDI12P GND AVDD_TX VDD_IO RXDO4N RXDO4P VDD_CMOS RXDO5N RXDO5P VDD_CMOS RXDO3N TXDI11N TXDI9P VDD_IO TXDI10N TXDI10P TXDI8P K RXDO6N RXDO6P VDD_IO RXDO7N RXDO7P VDD_IO RXDO8N RXDO8P VDD_IO TXDI9N TXDI7N TXDI7P VDD_IO TXDI8N L RXDO9N RXDO9P GND RXDO10N RXDO10P SE_REF RXDO11P TXDI5N TXDI5P GND TXDI6N TXDI6P GND M RXDO12N RXDO12P VDD_IO RXDO13N RXDO13P VDD_CMOS RXDO14P RXDO11N VDD_CMOS TXDI3N TXDI3P VDD_CMOS TXDI4N TXDI4P N HOST/HW TRST VDD_IO RXDO15N RXDO15P RXDO14N GND TXDI1N TXDI1P VDD_IO TXDI2N TXDI2P VDD_IO GND RXPCLKON RXPCLKOP GND GND TXPCLKIN TXPCLKIP GND TXDI0N TXDI0P 3 4 5 6 9 10 11 12 13 14 / CP_OUT G GND 3 H AVDD_RX J GND VDD_IO P TXCLKO16NTXCLKO16P 1 2 TXPCLKON TXPCLKOP 7 8 PRELIMINARY XRT91L82 2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER GND F xr REV. P1.0.5 GND FIGURE 2. 196 BGA PINOUT OF THE XRT91L82 (TOP VIEW) A XRT91L82 REV. P1.0.5 PRELIMINARY xr 2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER TABLE OF CONTENTS GENERAL DESCRIPTION .................................................................................................1 APPLICATIONS ...........................................................................................................................................1 FIGURE 1. BLOCK DIAGRAM OF XRT91L82 ...................................................................................................................................... 1 FEATURES ......................................................................................................................................................2 PRODUCT ORDERING INFORMATION ..................................................................................................2 FIGURE 2. 196 BGA PINOUT OF THE XRT91L82 (TOP VIEW).......................................................................................................... 3 TABLE OF CONTENTS ............................................................................................................ I PIN DESCRIPTIONS ..........................................................................................................4 COMMON CONTROL .....................................................................................................................................4 TRANSMITTER SECTION ..................................................................................................................................8 RECEIVER SECTION .......................................................................................................................................11 SERIAL MICROPROCESSOR INTERFACE .............................................................................................14 ...................................................................................................................................................................14 JTAG ..........................................................................................................................................................15 1.0 FUNCTIONAL DESCRIPTION .............................................................................................................16 1.1 HARDWARE MODE VS. HOST MODE .......................................................................................................... 16 1.2 CLOCK INPUT REFERENCE ......................................................................................................................... 16 TABLE 1: REFERENCE FREQUENCY OPTIONS (NORMAL MODE/ FEC RATE)...................................................................................... 16 1.3 ALTERNATE CLOCK INPUT REFERENCE (HOST MODE ONLY) .............................................................. 16 TABLE 2: ALTERNATE REFERENCE FREQUENCY OPTIONS (NORMAL MODE/ FEC RATE) ................................................................... 17 1.4 DATA LATENCY ............................................................................................................................................. 17 TABLE 3: DATA INGRESS TO DATA EGRESS LATENCY ....................................................................................................................... 17 1.5 FORWARD ERROR CORRECTION (FEC) .................................................................................................... 17 FIGURE 3. SIMPLIFIED BLOCK DIAGRAM OF FORWARD ERROR CORRECTION .................................................................................... 17 1.6 PRBS PATTERN GENERATOR AND ANALYZER ....................................................................................... 17 2.0 RECEIVE SECTION .............................................................................................................................18 2.1 RECEIVE SERIAL INPUT ............................................................................................................................... 18 FIGURE 4. RECEIVE SERIAL INPUT INTERFACE BLOCK ..................................................................................................................... 18 TABLE 4: DIFFERENTIAL CML INPUT SWING PARAMETERS .............................................................................................................. 18 2.2 EXTERNAL RECEIVE LOOP FILTER CAPACITORS ................................................................................... 19 FIGURE 5. EXTERNAL LOOP FILTER ................................................................................................................................................ 19 2.3 RECEIVE CLOCK AND DATA RECOVERY .................................................................................................. 19 TABLE 5: CLOCK AND DATA RECOVERY UNIT PERFORMANCE .......................................................................................................... 20 2.4 EXTERNAL SIGNAL DETECTION ................................................................................................................. 20 TABLE 6: LOSD DECLARATION POLARITY SETTING ......................................................................................................................... 20 2.5 RECEIVE SERIAL INPUT TO PARALLEL OUTPUT (SIPO) ......................................................................... 21 FIGURE 6. SIMPLIFIED BLOCK DIAGRAM OF SIPO ........................................................................................................................... 21 2.6 RECEIVE PARALLEL OUTPUT INTERFACE ............................................................................................... 21 FIGURE 7. RECEIVE PARALLEL OUTPUT INTERFACE BLOCK ............................................................................................................. 21 2.7 RECEIVE PARALLEL INTERFACE LVDS OPERATION .............................................................................. 22 FIGURE 8. LVDS EXTERNAL BIASING RESISTORS ............................................................................................................................. 22 2.8 PARALLEL RECEIVE DATA OUTPUT DISABLE/MUTE UPON LOSD ........................................................ 22 2.9 PARALLEL RECEIVE CLOCK OUTPUT DISABLE ...................................................................................... 22 2.10 RECEIVE PARALLEL DATA OUTPUT TIMING .......................................................................................... 22 FIGURE 9. RECEIVE PARALLEL OUTPUT TIMING .............................................................................................................................. 22 TABLE 7: RECEIVE PARALLEL DATA AND CLOCK OUTPUT TIMING SPECIFICATIONS ........................................................................... 22 3.0 TRANSMIT SECTION ..........................................................................................................................23 3.1 TRANSMIT PARALLEL INTERFACE ............................................................................................................ 23 FIGURE 10. TRANSMIT PARALLEL INPUT INTERFACE BLOCK ............................................................................................................. 23 3.2 TRANSMIT PARALLEL DATA INPUT TIMING ............................................................................................. 24 FIGURE 11. TRANSMIT PARALLEL INPUT TIMING .............................................................................................................................. 24 TABLE 8: TRANSMIT PARALLEL DATA AND CLOCK INPUT TIMING SPECIFICATION............................................................................... 24 TABLE 9: TRANSMIT PARALLEL CLOCK OUTPUT TIMING SPECIFICATION ........................................................................................... 24 3.3 TRANSMIT FIFO ............................................................................................................................................. 24 FIGURE 12. TRANSMIT FIFO AND SYSTEM INTERFACE .................................................................................................................... 25 3.4 FIFO CALIBRATION UPON POWER UP ....................................................................................................... 25 3.5 TRANSMIT PARALLEL INPUT TO SERIAL OUTPUT (PISO) ...................................................................... 25 FIGURE 13. SIMPLIFIED BLOCK DIAGRAM OF PISO ......................................................................................................................... 25 I xr PRELIMINARY 2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER XRT91L82 REV. P1.0.5 3.6 CLOCK MULTIPLIER UNIT (CMU) AND RE-TIMER ..................................................................................... 26 TABLE 10: CLOCK MULTIPLIER UNIT PERFORMANCE ....................................................................................................................... 26 3.7 LOOP TIMING AND CLOCK CONTROL ....................................................................................................... 26 TABLE 11: LOOP TIMING AND REFERENCE DE-JITTER CONFIGURATIONS ............................................................................................ 27 FIGURE 14. LOOP TIMING MODE USING AN EXTERNAL CLEANUP VCXO (HOST MODE ONLY) .......................................................... 27 3.8 EXTERNAL LOOP FILTER (HOST MODE ONLY) ........................................................................................ 28 FIGURE 15. SIMPLIFIED DIAGRAM OF THE EXTERNAL LOOP FILTER .................................................................................................. 28 3.9 TRANSMIT SERIAL OUTPUT CONTROL ..................................................................................................... 28 FIGURE 16. TRANSMIT SERIAL OUTPUT INTERFACE BLOCK .............................................................................................................. 28 TABLE 12: DIFFERENTIAL CML OUTPUT SWING PARAMETERS ......................................................................................................... 28 FIGURE 17. CML DIFFERENTIAL VOLTAGE SWING........................................................................................................................... 29 4.0 DIAGNOSTIC FEATURES ................................................................................................................... 30 4.1 SERIAL REMOTE LOOPBACK ..................................................................................................................... 30 FIGURE 18. SERIAL REMOTE LOOPBACK ......................................................................................................................................... 30 4.2 PARALLEL REMOTE LOOPBACK (HOST MODE ONLY) ........................................................................... 30 FIGURE 19. PARALLEL REMOTE LOOPBACK .................................................................................................................................... 30 4.3 DIGITAL LOCAL LOOPBACK ....................................................................................................................... 31 FIGURE 20. DIGITAL LOOPBACK...................................................................................................................................................... 31 4.4 SONET JITTER REQUIREMENTS ................................................................................................................. 32 4.4.1 JITTER TOLERANCE: ................................................................................................................................................ 32 FIGURE 21. JITTER TOLERANCE MASK............................................................................................................................................ 32 FIGURE 22. XRT91L82 MEASURED JITTER TOLERANCE IN LOOP TIMING MODE AT 2.488 GBPS STS-48/STM-16 ............................ 33 FIGURE 23. XRT91L82 MEASURED JITTER TOLERANCE IN LOOP TIMING MODE AT 2.666 GBPS FEC MODE ..................................... 33 4.4.2 JITTER TRANSFER .................................................................................................................................................... 33 FIGURE 24. XRT91L82 MEASURED JITTER TRANSFER IN LOOP TIMING MODE AT 2.488 GBPS STS-48/STM-16 .............................. 33 FIGURE 25. XRT91L82 MEASURED JITTER TRANSFER IN LOOP TIMING MODE AT 2.666 GBPS FEC MODE ....................................... 33 4.4.3 JITTER GENERATION................................................................................................................................................ 34 FIGURE 26. XRT91L82 MEASURED ELECTRICAL PHASE NOISE TRANSMIT JITTER GENERATION AT 2.488 GBPS .............................. 34 FIGURE 27. XRT91L82 MEASURED ELECTRICAL PHASE NOISE TRANSMIT JITTER GENERATION AT 2.666 GBPS .............................. 34 5.0 SERIAL MICROPROCESSOR INTERFACE BLOCK ......................................................................... 35 FIGURE 28. SIMPLIFIED BLOCK DIAGRAM OF THE SERIAL MICROPROCESSOR INTERFACE ................................................................. 35 5.1 SERIAL TIMING INFORMATION ................................................................................................................... 35 FIGURE 29. TIMING DIAGRAM FOR THE SERIAL MICROPROCESSOR INTERFACE ................................................................................ 35 5.2 16-BIT SERIAL DATA INPUT DESCRITPTION ............................................................................................. 36 5.2.1 5.2.2 5.2.3 5.2.4 R/W (SCLK1)............................................................................................................................................................... A[5:0] (SCLK2 - SCLK7)............................................................................................................................................. X (DUMMY BIT SCLK8) .............................................................................................................................................. D[7:0] (SCLK9 - SCLK16)........................................................................................................................................... 36 36 36 36 5.3 8-BIT SERIAL DATA OUTPUT DESCRIPTION ............................................................................................. 36 6.0 REGISTER MAP AND BIT DESCRIPTIONS ....................................................................................... 37 TABLE 13: TABLE 14: TABLE 15: TABLE 16: TABLE 17: TABLE 18: TABLE 19: TABLE 20: TABLE 21: TABLE 22: TABLE 23: TABLE 24: MICROPROCESSOR REGISTER MAP................................................................................................................................ 37 MICROPROCESSOR REGISTER 0X00H BIT DESCRIPTION ................................................................................................. 38 MICROPROCESSOR REGISTER 0X01H BIT DESCRIPTION ................................................................................................. 39 MICROPROCESSOR REGISTER 0X02H BIT DESCRIPTION ................................................................................................. 40 MICROPROCESSOR REGISTER 0X03H BIT DESCRIPTION ................................................................................................. 41 MICROPROCESSOR REGISTER 0X04H BIT DESCRIPTION ................................................................................................. 42 MICROPROCESSOR REGISTER 0X05H BIT DESCRIPTION ................................................................................................. 43 MICROPROCESSOR REGISTER 0X06H BIT DESCRIPTION ................................................................................................. 45 MICROPROCESSOR REGISTER 0X07H BIT DESCRIPTION ................................................................................................. 46 MICROPROCESSOR REGISTER 0X3CH BIT DESCRIPTION ................................................................................................. 48 MICROPROCESSOR REGISTER 0X3DH BIT DESCRIPTION ................................................................................................. 49 MICROPROCESSOR REGISTER 0X3FH BIT DESCRIPTION ................................................................................................. 49 7.0 ELECTRICAL CHARACTERISTICS ................................................................................................... 50 ABSOLUTE MAXIMUM RATINGS .................................................................................................................. 50 ABSOLUTE MAXIMUM POWER AND INPUT LOGIC SIGNALS ............................................................. 50 POWER AND CURRENT DC ELECTRICAL CHARACTERISTICS .................................................................... 50 LVPECL LOGIC SIGNAL DC ELECTRICAL CHARACTERISTICS .......................................................... 51 LVDS LOGIC SIGNAL DC ELECTRICAL CHARACTERISTICS............................................................... 51 LVTTL/LVCMOS SIGNAL DC ELECTRICAL CHARACTERISTICS ........................................................... 52 ORDERING INFORMATION .................................................................................................................. 53 196 SHRINK THIN BALL GRID ARRAY .............................................................................................. 53 (15.0 MM X 15.0 MM, STBGA).......................................................................................................... 53 II XRT91L82 REV. P1.0.5 PRELIMINARY xr 2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER REV. 1.00.......................................................................................................................................... 53 REVISION HISTORY.......................................................................................................................................54 III xr PRELIMINARY XRT91L82 2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER REV. P1.0.5 PIN DESCRIPTIONS COMMON CONTROL NAME LEVEL TYPE PIN DESCRIPTION RESET LVTTL, LVCMOS I E5 Master Reset Input Active low signal. When this pin is pulled "Low" for more than 30ns, the internal registers are set to their default state. See the register description for the default values. This pin is provided with an internal pull-up. PIO_CFG1 PIO_CFG0 LVTTL, LVCMOS I D3 E3 Parallel I/O Configuration Selects parallel I/O to be differential LVDS, differential LVPECL, or Single-Ended LVPECL based on table below. PIO_CFG [1:0] VDD_I/O Input Configuration Output Configuration 00 3.3V 3.3V Differential LVPECL 3.3V Differential LVPECL 01 3.3V 3.3V Single-Ended LVPECL 3.3V Single-Ended LVPECL 10 3.3V 3.3V Differential LVDS 3.3V Differential LVDS 11 Reserved This pin is provided with an internal pull-down. XRES1P XRES1N - I E14 F14 External LVDS Biasing Resistors A 402Ω resistor with +/-1% tolerance should be placed across these 2 pins for proper biasing. Although unecessary in LVPECL operation, this resistor is required in LVDS operation. See Figure 8 on page 22. SE_REF Analog O L7 Single-Ended LVPECL Biasing Output Reference VBB 100K output bias reference. Maximum load capacitance is 30pF. Maximum sourcing/sinking capability is 750µA and 1000µA respectively. SEREFDIS LVTTL, LVCMOS I C3 SE_REF Power down Control Powers down SE_REF and reduces power consumption. "Low" = SE_REF Enabled "High" = SE_REF Disabled This pin is provided with an internal pull-up. REF1CLKP REF1CLKN LVPECL Diff I A13 B13 Reference Clock Input 1 This differential clock input reference is used for the transmit clock multiplier unit (CMU) and clock data recovery (CDR) to provide the necessary high-speed clock reference for this device. Pin REFREQSEL[1:0] determines the value used as the reference. See Pin REFREQSEL[1:0] for more details. Internally terminated and biased. 4 xr XRT91L82 PRELIMINARY 2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER REV. P1.0.5 COMMON CONTROL NAME LEVEL TYPE PIN DESCRIPTION REF2CLKP REF2CLKN LVPECL Diff I A11 B11 Reference Clock Input 2 This differential clock input reference is used for the transmit clock multiplier unit (CMU) and clock data recovery (CDR) to provide the necessary high-speed clock reference for this device. Pin REFREQSEL[1:0] determines the value used as the reference. See Pin REFREQSEL[1:0] for more details. Internally terminated and biased. REFREQSEL1 / SCLK LVTTL, LVCMOS I D12 Reference Clock Frequency Select Hardware Mode REFREQSEL1 pin is used to select the frequency of the REF1CLK and/or REF2CLK input to the CMU and CDR. REFREQSEL [1:0] CMU CDR REFERENCE FREQUENCY REFERENCE FREQUENCY 00 155.52 MHz present on 155.52 MHz present on REF1CLK REF1CLK REF2CLK not used REF2CLK not used 01 155.52 MHz present on 166.63 MHz present on REF1CLK REF2CLK 10 166.63 MHz present on 155.52 MHz present on REF2CLK REF1CLK 11 166.63 MHz present on 166.63 MHz present on REF2CLK REF2CLK REF1CLK not used REF1CLK not used NOTE: Non-FEC rates require 155.52 MHz clock reference. FEC rates require 166.63 MHz clock reference This pin is provided with an internal pull-down. Host Mode This pin is functions as the microprocessor Serial Clock Input. REFREQSEL0 LVTTL, LVCMOS I E12 Reference Clock Frequency Select REFREQSEL0 pin is used to select the frequency of the REF1CLK and/or REF2CLK input to the CMU and CDR. REFREQSEL [1:0] CMU CDR REFERENCE FREQUENCY REFERENCE FREQUENCY 00 155.52 MHz present on 155.52 MHz present on REF1CLK REF1CLK REF2CLK not used REF2CLK not used 01 155.52 MHz present on 166.63 MHz present on REF1CLK REF2CLK 10 166.63 MHz present on 155.52 MHz present on REF2CLK REF1CLK 11 166.63 MHz present on 166.63 MHz present on REF2CLK REF2CLK REF1CLK not used REF1CLK not used NOTE: Non-FEC rates require 155.52 MHz clock reference. FEC rates require 166.63 MHz clock reference This pin is provided with an internal pull-down. 5 xr PRELIMINARY XRT91L82 2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER REV. P1.0.5 COMMON CONTROL NAME LEVEL TYPE PIN PRBS_EN LVTTL, LVCMOS I D9 DESCRIPTION 223-1 PRBS TEST Pattern Enable Generates 223-1 Pseudo Random Binary Sequence test patterns and analyzes in the receiving block for proper reception. "Low" = Normal Mode "High" = PRBS pattern generator and analyzer Enabled. NOTE: A Local Loopback of some type such as Digital Local Loopback or an optical cable loopback is expected to be used in conjunction with PRBS_EN in order for the PRBS analyzer to receive the PRBS pattern. This pin is provided with an internal pull-down. PRBS_ERR /SDO LVCMOS O E9 223-1 PRBS Pattern Validation Error Hardware Mode Indicates an error condition has occurred/is occuring in the validation of generated PRBS pattern. "Low" = Un-erred transmission and reception of PRBS pattern. "High" = Error Condition occurrence. Host Mode This pin is functions as the microprocessor Serial Data Output. RLOOPS_ PRBSCLR LVTTL, LVCMOS I F11 Serial Remote Loopback Normal Mode The serial remote loopback mode interconnects the receive serial data input to the transmit serial data output. If serial remote loopback is enabled, the 16-bit parallel transmit data input is ignored while the 16-bit parallel receive data output and parallel receive clock output is maintained. "Low" = Serial Remote Loopback Mode Enabled "High" = Disabled PRBSTest Mode When PRBS_EN is asserted, this bit is used to clear or reset PRBS_ERR error condition. Serial Remote Loopback is not available in PRBS Test Mode. "Low" = Clears PRBS_ERR condition "High" = Normal Mode This pin is provided with an internal pull-up. 6 xr XRT91L82 PRELIMINARY 2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER REV. P1.0.5 COMMON CONTROL NAME LEVEL TYPE PIN DESCRIPTION DLOOP LVTTL, LVCMOS I E11 Digital Local Loopback The digital local loopback mode interconnects the 16-bit parallel transmit data and parallel transmit clock input to the 16-bit parallel receive data and parallel receive clock output respectively while maintaining the transmit serial data output. If digital local loopback is enabled, the receive serial data input is ignored. "Low" = Digital Local Loopback Mode Enabled "High" = Disabled This pin is provided with an internal pull-up. LOOPTM_NOJA / SDI LVTTL, LVCMOS I C10 Loop Timing Mode With No Jitter Attenuation Hardware Mode When the loop timing mode is activated, the external local reference clock input to the CMU is replaced with the 1/16th of the high-speed recovered receive clock coming from the CDR. "Low" = Disabled "High" = Loop timing Activated This pin is provided with an internal pull-down. Host Mode This pin is functions as the microprocessor Serial Data Input. 7 xr PRELIMINARY XRT91L82 2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER REV. P1.0.5 TRANSMITTER SECTION NAME LEVEL TYPE PIN DESCRIPTION TXDI0P TXDI0N TXDI1P TXDI1N TXDI2P TXDI2N TXDI3P TXDI3N TXDI4P TXDI4N TXDI5P TXDI5N TXDI6P TXDI6N TXDI7P TXDI7N TXDI8P TXDI8N TXDI9P TXDI9N TXDI10P TXDI10N TXDI11P TXDI11N TXDI12P TXDI12N TXDI13P TXDI13N TXDI14P TXDI14N TXDI15P TXDI15N LVDS, LVPECL Diff and SE I P14 P13 N10 N9 N13 N12 M11 M10 M14 M13 L10 L9 L13 L12 K12 K11 J14 K14 J10 K10 J13 J12 H9 J9 H12 H11 G11 G10 F12 G12 G8 G7 Transmit Parallel Data Input The 155.52 Mbps 16-bit parallel transmit data input should be applied to the transmit parallel bus simultaneously to be sampled at the rising edge of the TXPCLKIP/N input. The 16-bit parallel interface is multiplexed into the transmit serial output interface, MSB first (TXDI15P/N). TXDI[15:0]P/N 100 Ω internal termination is controlled by INTERM pin or register bit. Inputs are internally biased to VDD_IO - 1V for AC coupled applications. For LVPECL Single-Ended applications, either a 100K VBB bias reference must be provided or the SE_REF pin can also be used to bias and connected all the negative polarity "N" pins. TXOP TXON CMLDIFF O A6 A5 Transmit Serial Data Output The transmit serial data output stream is generated by multiplexing the 16-bit parallel transmit data input into a 2.488 Gbps serial data output stream. In Forward Error Correction, the transmit serial data output stream is 2.666 Gbps. TXSWING / INT LVTTL, LVCMOS I/O D10 NOTE: The XRT91L82 can accept 166.63 Mbps 16-bit parallel transmit data input for Forward Error Correction (FEC) Applications. Transmit Serial CML Output Swing Mode Hardware Mode Selects the generated transmit serial CML Output swing to the optical module. "Low" = Low Swing CML Mode "High" = High Swing CML Mode This pin is provided with an internal pull-up. Host Mode This pin is functions as the microprocessor Interrupt Output. NOTE: This pin becomes an open drain output in Host Mode and requires an external pull-up resistor. 8 xr XRT91L82 PRELIMINARY 2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER REV. P1.0.5 TRANSMITTER SECTION NAME LEVEL TYPE PIN DESCRIPTION TXSCLKOP TXSCLKON CMLDIFF O A9 A8 2.488/2.666 GHz Transmit Serial Clock Output A high-speed 2.488/2.666 GHz Transmit serial clock output that can be used to retime TXOP/N. TXSCLKOOFF / CS LVTTL, LVCMOS I C9 2.488/2.666 GHz Hi-speed Serial Clock Output Tristate Hardware Mode Tristates TXSCLKOP/N output and reduces power consumption. "Low" = TXSCLKOP/N output Enabled "High" = Tristates TXSCLKOP/N output This pin is provided with an internal pull-up. Host Mode This pin is functions as the microprocessor Chip Select Input. INTERM / VCXO_IN LVTTL, LVCMOS / SELVCMOS I E4 Transmit Parallel Bus Input Internal Termination Hardware Mode Provides 100Ω line-to-line internal termination to TXDI[15:0]P/N and TXPCLKIP/N. "Low" = Disabled "High" = TXDI[15:0]P/N and TXPCLKIP/N internally terminated. This pin is provided with an internal pull-down. Host Mode - Voltage Controled 77.76/83.31 MHz or 155.52/ 166.63 MHz External Oscillator Input This 77.76/83.31 MHz or 155.52/166.63 MHz Single-Ended LVCMOS clock input is used for the transmit PLL jitter attenuation. ALTFREQSEL register bit determines the value used as the reference. Software register bit VCXOSEL allows the selection of the De-Jitter VCXO Mode. See ALTFREQSEL and VCXO_SEL software register bit description for more details. TXPCLKIP TXPCLKIN LVDS, LVPECL Diff and SE I P11 P10 Transmit Parallel Clock Input 155.52 MHz clock input used to sample the 16-bit parallel transmit data input TXDI[15:0]P/N. TXPCLKIP/N 100 Ω internal termination is controlled by INTERM pin or register bit. TXPCLKIP/N inputs are internally biased to VDD_IO - 1V for AC coupled application. NOTE: The XRT91L82 can accept a 166.63 MHz transmit clock input for Forward Error Correction (FEC) Applications. TXPCLKOP TXPCLKON LVDS, LVPECL Diff and SE O P8 P7 Transmit Parallel Clock Output This 155.52 MHz clock can be used for the downstream device to generate the TXDI[15:0]P/N data and TXPCLKIP/N clock input. This enables the downstream device and the STS-48 transceiver to be in synchronization. NOTE: The XRT91L82 can output a 166.63 MHz transmit clock output for Forward Error Correction (FEC). 9 xr PRELIMINARY XRT91L82 2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER REV. P1.0.5 TRANSMITTER SECTION NAME LEVEL TYPE PIN DESCRIPTION TXCLKO16P TXCLKO16N LVDS, LVPECL Diff and SE O P2 P1 Auxiliary Clock Output (155.52/19.44 MHz) 155.52 or 19.44 MHz auxiliary clock derived from CMU output. This clock can also be used for the downstream device as a reference for generating the TXDI[15:0]P/N data and TXPCLKIP/ N clock input. This enables the downstream device and the STS-48 transceiver to be in synchronization. The frequency output of this pin is controlled by TXCLKO16SEL. NOTE: This pin can output a 166.63/20.83 MHz transmit clock output for Forward Error Correction (FEC). TXCLKO16SEL LVTTL, LVCMOS I C4 Auxiliary Clock Output Select This pin is used to select the auxiliary clock output. "Low" = TXCLKO16P/N outputs 155.52/ 166.63 MHz "High" = TXCLKO16P/N outputs 19.44/ 20.83 MHz This pin is provided with an internal pull-down. LOCKDET_CMU LVCMOS O C6 CMU Lock Detect This pin is used to monitor the lock condition of the clock multiplier unit. "Low" = CMU Out of Lock "High" = CMU Locked OVERFLOW LVCMOS O D6 Transmit FIFO Overflow This pin is used to monitor the transmit FIFO status. "Low" = Normal Status "High" = Overflow Condition FIFO_RST LVTTL, LVCMOS I D5 FIFO Control Reset FIFO_RST should be held "High" for a minimum of 2 TXPCLKOP/N cycles after powering up and during manual FIFO reset. After the FIFO_RST pin is returned "Low," it will take 8 to 10 TXPCLKOP/N cycles for the FIFO to flush out. Upon an interrupt indication that the FIFO has an overflow condition, this pin is used to reset or flush out the FIFO. "Low" = Normal Operation "High" = Manual FIFO Reset This pin is provided with an internal pull-down. NOTES: 1. In Hardware Mode, to automatically reset the FIFO, tie the OVERFLOW output pin to the FIFO_RST input pin or if desired, an asynchronous FIFO reset pin and the OVERFLOW output pin can be logically ’OR’ed and the output tied to the FIFO_RST input pin. 2. In Host Mode, this pin is disabled and not used. FIFO_RST is asserted through Microprocessor Control Register 0x03H Bit-D0. A FIFO_AUTORST bit is also available on Microprocessor Control Register 0x03H BitD1. 10 xr XRT91L82 PRELIMINARY 2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER REV. P1.0.5 RECEIVER SECTION NAME LEVEL TYPE PIN DESCRIPTION RXDO0P RXDO0N RXDO1P RXDO1N RXDO2P RXDO2N RXDO3P RXDO3N RXDO4P RXDO4N RXDO5P RXDO5N RXDO6P RXDO6N RXDO7P RXDO7N RXDO8P RXDO8N RXDO9P RXDO9N RXDO10P RXDO10N RXDO11P RXDO11N RXDO12P RXDO12N RXDO13P RXDO13N RXDO14P RXDO14N RXDO15P RXDO15N LVDS, LVPECL Diff and SE O G5 G4 H4 H3 H7 H6 H8 J8 J3 J2 J6 J5 K2 K1 K5 K4 K8 K7 L3 L2 L6 L5 L8 M8 M2 M1 M5 M4 M7 N7 N6 N5 Receive Parallel Data Output 155.52 Mbps 16-bit parallel receive data output is updated simultaneously on the falling edge of the RXPCLKOP/N output. The 16-bit parallel interface is de-multiplexed from the receive serial data input, MSB first (RXDO15P/N). For LVPECL SingleEnded applications, all the negative polarity "N" pins should not be connected. RXIP RXIN CMLDIFF I A2 A3 Receive Serial Data Input The receive serial data stream of 2.488 Gbps is applied to these input pins. In Forward Error Correction, the receive serial data stream is 2.666 Gbps. This pin is internally biased and terminated. RXPCLKOP RXPCLKON LVDS, LVPECL Diff and SE O P5 P4 Receive Parallel Clock Output 155.52 MHz parallel clock output used to update the 16-bit parallel receive data output RXDO[15:0]P/N at the falling edge of this clock. NOTE: The XRT91L82 can output 166.63 Mbps 16-bit parallel receive data output for Forward Error Correction (FEC) Applications. NOTE: The XRT91L82 can output a 166.63 MHz receive clock output for Forward Error Correction (FEC). 11 xr PRELIMINARY XRT91L82 2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER REV. P1.0.5 RECEIVER SECTION NAME LEVEL TYPE PIN DESCRIPTION CDRLCKREF LVTTL, LVCMOS I C12 CDR’s Recovered High-speed Serial Clock Reference Controls CDR’s operation. "Low" = Forced to lock to CDR PLL reference training clock "High" = Normal Operation (Locked to incoming serial data) This pin is provided with an internal pull-up. DISRD /PRBS_LOCK LVTTL, LVCMOS I/O D4 Receive Parallel Data Output Disable Hardware Mode If this pin is set to "0", the 16-bit parallel receive data output will asynchronously mute. "Low" = Forces RXDO[15:0]P/N to a logic state of "0" "High" = Normal Mode This pin is provided with an internal pull-up. Host Mode 223-1 PRBS Pattern Lock Output Indicator This pin indicates the current state condition of the PRBS pattern analyzer when the PRBS pattern generator is enabled. "Low" = PRBS pattern analyzer currently Out of Lock "High" = PRBS pattern analyzer currently Locked DISRDCLK LVTTL, LVCMOS I D11 Receive Parallel Clock Output Disable This pin is used to asynchronously control the activity of the parallel receive clock output. "Low" = Forces RXPCLKOP/N to a logic state of "0" "High" = Normal Mode This pin is provided with an internal pull-up. LOCKDET_CDR LVCMOS O C5 CDR Lock Detect This pin is used to monitor the lock condition of the clock and data recovery unit. "Low" = CDR Out of Lock "High" = CDR Locked SDEXT LVTTL, LVCMOS I C2 Signal Detect Input from Optical Module When inactive, it will automatically mute received data output bus RXDO[15:0]P/N upon Loss of Signal Detection (LOSD) condition. "Active" = Normal Operation (SDEXT detects signal presence) "Inactive" =Mutes upon LOSD (SDEXT detects signal absence) This pin is provided with an internal pull-up. POLARITY LVTTL, LVCMOS I E10 Polarity for SDEXT Input Controls the Signal Detect polarity convention of SDEXT. "Low" = SDEXT is active "Low" "High" = SDEXT is active "High" This pin is provided with an internal pull-up. 12 xr XRT91L82 PRELIMINARY 2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER REV. P1.0.5 RECEIVER SECTION NAME LEVEL TYPE PIN DESCRIPTION RXCAP1P Analog I E1 External Receive Loop Filter Hardware Mode This pin is required for the external loop filter capacitor and resistors. See Figure 5 on page 19. Host Mode - No Connect This pin is not connected in Host Mode. RXCAP1N / CP_OUT Analog I/O F1 External Receive Loop Filter Hardware Mode This pin is required for the external loop filter capacitor and resistors. See Figure 5 on page 19. Host Mode - Charge Pump Output (for external VCXO) The nominal output of the charge pump current is 250µA. POWER AND GROUND NAME TYPE PIN DESCRIPTION AVDD_RX PWR C1, D2, G2, H1 Analog 1.8V Receiver Power Supply AVDD_RX should be isolated from the digital power supplies. For best results, use a ferrite bead along with an internal power plane separation. The AVDD_RX power supply pins should have bypass capacitors to the nearest ground. AVDD_TX PWR C14, D13, G13, H14 Analog 1.8V Transmitter Power Supply AVDD_TX should be isolated from the digital power supplies. For best results, use a ferrite bead along with an internal power plane separation. The AVDD_TX power supply pins should have bypass capacitors to the nearest ground. VDD_CML PWR A4, A7, A10, A12, B3, B5, B7, B9, C11, C13 CML 1.8V Power Supply These pins require a 1.8V potential. VDD_CMOS PWR E6, E8, F3, F5, F7, F9, J4, J7, M6, M9, M12 Digital 1.8V Power Supply VDD_CMOS should be isolated from the analog power supplies. For best results, use a ferrite bead along with an internal power plane separation. The VDD_CMOS power supply pins should have bypass capacitors to the nearest ground. VDD_IO PWR G3, G9, J1, J11, K3, K6, K9, K13, M3, N1, N4, N11, N14 3.3V LVPECL/ 3.3V LVDS Input /Output Bus Power Supply and 3.3V Digital I/O Power Supply These pins require a 3.3V potential in LVPECL or LVDS operation. These pins also power the 3.3V Digital I/O Power Supply. GND GND A1, A14, B1, B2, B4, B6, B8, B10, B12, B14, D1, D14, E2, E7, E13, F2, F4, F6, F8, F10, F13, G1, G6, G14, H2, H5, H10, H13, L1, L4, L11, L14, N8, P3, P6, P9, P12 Ground for 3.3V / 1.8V Digital Power Supplies It is recommended that all ground pins of this device be tied together. NOTE: For VDDIO=3.3V, all input control pins are LVCMOS and LVTTL compatible. All output control pins are LVCMOS compatible only. 13 xr PRELIMINARY XRT91L82 2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER REV. P1.0.5 SERIAL MICROPROCESSOR INTERFACE NAME LEVEL TYPE PIN DESCRIPTION HOST/HW LVTTL, LVCMOS I N2 Host or Hardware Mode Select Input The XRT91L82 offers two modes of operation for interfacing to the device. The Host mode uses a serial microprocessor interface for programming individual registers. The Hardware mode is controlled by the state of the hardware pins set by the user. When left unconnected, by default, the device is configured in the Hardware mode. "Low" = Hardware Mode "High" = Host Mode This pin is provided with an internal pull-down. TXSCLKOOFF / CS LVTTL, LVCMOS I C9 Chip Select Input (Host Mode Only) Active "Low" signal. This signal enables the serial microprocessor interface by pulling chip select "Low". The serial microprocessor is disabled when the chip select signal returns "High". NOTES: 1. The serial microprocessor interface does not support burst mode. Chip Select must be de-asserted after each operation cycle. 2. Chip Select is only active in Host Mode. This pin is provided with an internal pull-up. REFREQSEL1 / SCLK LVTTL, LVCMOS I D12 Serial Clock Input (Host Mode Only) Once CS is pulled "Low", the serial microprocessor interface requires 16 clock cycles for a complete Read or Write operation. Serial Clock Input is only active in Host Mode. This pin is provided with an internal pull-down. LOOPTM_NOJA / SDI LVTTL, LVCMOS I C10 Serial Data Input (Host Mode Only) When CS is pulled "Low", the serial data input is sampled on the rising edge of SCLK. Serial Data Input is only active in Host Mode. This pin is provided with an internal pull-down. PRBS_ERR / SDO LVCMOS O E9 Serial Data Output (Host Mode Only) If a Read function is initiated, the serial data output is updated on the falling edge of SCLK8 through SCLK15, with the LSB (D0) updated first. This enables the data to be sampled on the rising edge of SCLK9 through SCLK16. Serial Data Output is only active in Host Mode. TXSWING / INT LVCMOS O D10 Interrupt Output (Host Mode Only) Active "Low" signal. This signal is asserted "Low" when a change in alarm status occurs. Once the status registers have been read, the interrupt pin will return "High". Interrupt Output is only active in Host Mode. NOTE: This pin is an open drain output and requires an external pull-up resistor. 14 xr XRT91L82 PRELIMINARY 2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER REV. P1.0.5 JTAG SIGNAL NAME PIN # TYPE DESCRIPTION TCK C7 I Test clock: Boundary Scan Clock Input. This pin is provided with an internal pull-down. TMS D8 I Test Mode Select: Boundary Scan Mode Select Input. JTAG is disabled by default. Note: This input pin should be pulled “Low” for JTAG operation This pin is provided with an internal pull-up. TDI C8 I Test Data In: Boundary Scan Test Data Input This pin is provided with an internal pull-up. TDO D7 O Test Data Out: Boundary Scan Test Data Output TRST N3 I JTAG Test Reset Input Note: This input pin should be pulled “Low” to reset JTAG This pin is provided with an internal pull-up. NO CONNECTS NAME LEVEL TYPE PIN None N/A N/A None DESCRIPTION No Connect This pin can be left floating or tied to ground. 15 xr PRELIMINARY XRT91L82 2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER REV. P1.0.5 1.0 FUNCTIONAL DESCRIPTION The XRT91L82 Transceiver is designed to operate with a SONET Framer/ASIC device and provide a highspeed serial interface to optical networks. The Transceiver converts 16-bit parallel data at 155.52/166.63 MHz to a serial CML bit stream at 2.488/2.666 Gbps and vice-versa. It implements a clock multiplier unit (CMU), SONET/SDH serialization/de-serialization (SerDes), and receive clock and data recovery (CDR) unit. The Transceiver is divided into Transmit and Receive sections and is used to provide the front end component of SONET equipment, which includes primarily serial transmit and receive functions. 1.1 Hardware Mode vs. Host Mode Functionality of the STS-48/STM-16 Transceiver can be configured by using either Host mode or Hardware mode. Hardware mode is selected by pulling HOST/HW "Low" or leaving this pin unconnected. The transceiver functionality is then controlled by the hardware pins described in the Hardware Pin Descriptions. However, if Host mode is selected by pulling HOST/HW "High", the functionality is controlled by programming internal R/W registers using the Serial Microprocessor interface. Whether using Host or Hardware mode, the functionality remains the same. Therefore, the following sections describe the functionality rather than how each function is controlled. The Hardware Pin Descriptions and the Register Bit Descriptions concentrate on configuring the device. 1.2 Clock Input Reference The XRT91L82 can accept both 155.52 MHz non-FEC or 166.63 MHz FEC clock input at REF1CLKP/N and/or REF2CLKP/N as its internal timing reference for generating higher speed clocks. The reference clock can be provided with one of two frequencies chosen by REFREQSEL[1:0]. The reference frequency options for the XRT91L82 are listed in Table 1. TABLE 1: REFERENCE FREQUENCY OPTIONS (NORMAL MODE/ FEC RATE) REFREQSEL CMU REFERENCE CDR REFERENCE CLOCK CLOCK [1:0] FREQUENCY FREQUENCY 1.3 REF1CLK CLOCK FREQUENCY REF2CLK CLOCK FREQUENCY TRANSMIT DATA RATE RECEIVE DATA RATE 00 REF1CLK REF1CLK 155.52 MHz non-FEC not used 2.488 Gbps non-FEC 2.488 Gbps non-FEC 01 REF1CLK REF2CLK 155.52 MHz non-FEC 166.63 MHz FEC 2.488 Gbps non-FEC 2.666 Gbps FEC 10 REF2CLK REF1CLK 155.52 MHz non-FEC 166.63 MHz FEC 2.666 Gbps FEC 2.488 Gbps non-FEC 11 REF2CLK REF2CLK not used 166.63 MHz FEC 2.666 Gbps FEC 2.666 Gbps FEC Alternate Clock Input Reference (Host Mode Only) In Host mode, the XRT91L82 has the option to accept a lower reference frequency of 77.76 MHz non-FEC or 83.31 MHz FEC clock input at REF1CLKP/N and/or REF2CLKP/N. To use this feature, register bit ALTFREQSEL must be set "Low" on bit- D5 of ”Configuration Control Register (0x07h)”. The alternate reference frequency options are listed below in Table 2. 16 xr XRT91L82 PRELIMINARY 2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER REV. P1.0.5 TABLE 2: ALTERNATE REFERENCE FREQUENCY OPTIONS (NORMAL MODE/ FEC RATE) REFREQSEL CMU REFERENCE CDR REFERENCE CLOCK CLOCK [1:0] FREQUENCY FREQUENCY 1.4 REF1CLK CLOCK FREQUENCY REF2CLK CLOCK FREQUENCY TRANSMIT DATA RATE RECEIVE DATA RATE 00 REF1CLK REF1CLK 77.76 MHz non-FEC not used 2.488 Gbps non-FEC 2.488 Gbps non-FEC 01 REF1CLK REF2CLK 77.76 MHz non-FEC 83.31 MHz FEC 2.488 Gbps non-FEC 2.666 Gbps FEC 10 REF2CLK REF1CLK 77.76 MHz non-FEC 83.31 MHz FEC 2.666 Gbps FEC 2.488 Gbps non-FEC 11 REF2CLK REF2CLK not used 83.31 MHz FEC 2.666 Gbps FEC 2.666 Gbps FEC Data Latency Due to different operating modes and data logic paths through the device, there is an associated latency from data ingress to data egress. Table 3 specifies the data latency for a typical path. TABLE 3: DATA INGRESS TO DATA EGRESS LATENCY MODE OF OPERATION DATA PATH Thru-mode 1.5 CLOCK REFERENCE Data on TXDI[15:0]P/N to data on TXOP/N MAXIMUM REFNCLK CLOCK CYCLES REF1CLKP/N or REF2CLKP/N Clock 18 to 20 Forward Error Correction (FEC) Forward Error Correction is used to control errors along a one-way path of communication. FEC sends extra information along with data which can be used by a receiver to check and correct the data without requesting re-transmission of the original information. It does so by introducing a known structure into a data sequence prior to transmission. The most common methods are to replace a 14-bit data packet with a 15-bit codeword structure, or to replace a 17-bit data packet with an 18-bit codeword structure. The XRT91L82 supports FEC by accepting a clock input reference frequency of 83.31 or 166.63 MHz. Both reference frequencies allows the transmit 16-bit parallel data input to be applied to the STS-48 transceiver at 166.63 Mbps which is converted to a 2.666 Gbps serial output stream to an optical module. A simplified block diagram of FEC is shown in Figure 3. Optical Fiber 16 STS-48 Transceiver Optical Module Optical Module 16 SONET/Framer ASIC 16 16 1.6 STS-48 Transceiver FEC codec SONET/Framer ASIC FEC codec FIGURE 3. SIMPLIFIED BLOCK DIAGRAM OF FORWARD ERROR CORRECTION PRBS Pattern Generator and Analyzer The XRT91L82 contains an on-chip Pseudo Random Binary Sequence (PRBS) generator and detector for diagnostic purpose. With the PRBS_EN asserted, the transmitter will send out PRBS pattern of 223-1 in STS48/48c or STM-16 rate. At the same time, the receiver PRBS detector is also enabled. Whenever the PRBS detector is not in sync, the PRBS_ERR bit will be set to “1”. To clear the erred condition, PRBSCLR must be toggled "Low." If the correct PRBS pattern is detected by the receiver, then PRBS_ERR pin will go “Low” to indicate PRBS synchronization has been achieved, otherwise PRBS_ERR will remain "1." PRBSCLR shares pin F11 with RLOOPS. Serial Remote Line Loopback (RLOOPS) is disabled when PRBS_EN is enabled. 17 xr PRELIMINARY XRT91L82 2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER REV. P1.0.5 2.0 RECEIVE SECTION The receive section of XRT91L82 includes the differential inputs RXIP/N, followed by the clock and data recovery unit (CDR) and receive serial-to-parallel converter. The receiver accepts the high-speed Non-Return to Zero (NRZ) serial data at 2.488/2.666 Gbps through the differential input interfaces RXIP/N. The clock and data recovery unit recovers the high-speed receive clock from the incoming scrambled NRZ data stream. The recovered serial data is converted into 16-bit-wide 155.52/166.63 Mbps parallel data and presented to the RXDO[15:0]P/N parallel interface. This parallel interface can be configured for Differential LVPECL/LVDS, or Single-Ended LVPECL operation. A divide-by-16 version of the high-speed recovered clock, RXPCLKOP/N is used to synchronize the transfer of the 16-bit RXDO[15:0]P/N data with the receive portion of the upstream device. Upon initialization or loss of signal or loss of lock the 155.52 MHz or 166.63 MHz external local reference clock is used to start-up the clock recovery phase-locked loop for proper operation. In Host Mode, a special loopback feature can be configured when parallel remote loopback (RLOOPP) is used in conjunction with de-jittered loop-time mode that allows the re-transmitted data to comply with ITU and Bellcore jitter generation specifications. 2.1 Receive Serial Input The receive serial CML inputs are applied to RXIP/N. The receive serial inputs can be AC or DC coupled to an optical module or an electrical interface. A simplified AC coupled block diagram is shown in Figure 4. FIGURE 4. RECEIVE SERIAL INPUT INTERFACE BLOCK 0.1µF RXIP Optical Module RXIN Optical Fiber 0.1µF XRT91L82 STS-48/ STM-16 Transceiver NOTE: Some optical modules integrate AC coupled capacitors within the module. If so, the external AC coupled capacitors are not necessary and can be excluded. The 2.488/2.666 Gbps high-speed differential CML RXIP/N input swing characteristics is shown in Table 4. Figure 17, “CML Differential Voltage Swing,” on page 29 shows the CML differential voltage swing. TABLE 4: DIFFERENTIAL CML INPUT SWING PARAMETERS PARAMETER DESCRIPTION MIN TYP MAX UNITS ∆VINDIFF Differential Input Voltage Swing 100 2000 mV ∆VINSE Single-Ended Input Voltage Swing 50 1000 mV ∆VINBIAS Input Bias Range (AC Coupled) VDD_CML - 0.4 VDD_CML - 0.2 V RDIFF Differential Input Resistance 120 Ω 80 18 100 xr XRT91L82 PRELIMINARY 2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER 2.2 REV. P1.0.5 External Receive Loop Filter Capacitors These external loop filter 0Ω resistors and 22µF non-polarized capacitor provide the necessary components to achieve the required receiver jitter performance. They must be well isolated to prohibit noise entering the CDR block. Figure 5 shows the pin connections and external loop filter components. The external loop filter is not needed while in host mode and RXCAP1N becomes the charge pump output for the external VCXO. FIGURE 5. EXTERNAL LOOP FILTER 0Ω pin E1 22uF non-polarized RXCAP1P 0Ω RXCAP1N pin F1 CP_OUT (HOST) 2.3 Receive Clock and Data Recovery The clock and data recovery unit accepts the high-speed NRZ serial data from the differential CML receiver and generates a clock that is the same frequency as the incoming data. The clock recovery utilizes REF1CLKP/N and/or REF2CLKP/N to train and monitor its clock recovery PLL. Initially upon startup, the PLL locks to the local reference clock within ±500 ppm. Once this is achieved, the PLL then attempts to lock onto the incoming receive data stream. Whenever the recovered clock frequency deviates from the local reference clock frequency by more than approximately ±500 ppm, the clock recovery PLL will switch and lock back onto the local reference clock. When this condition occurs the PLL will declare Loss of Lock and the LOCKDET_CDR signal will be pulled "Low." Whenever a Loss of Lock/Loss of Signal Detection (LOSD) event occurs, the CDR will continue to supply a receive clock (based on the local reference clock) to the upstream framer device. A Loss of Lock condition will also be declared when the external SDEXT becomes inactive. When the SDEXT is de-asserted by the optical module or when DISRD is asynchronously asserted "Low," receive parallel data output will be forced to a logic zero state for the entire duration that a LOSD condition is detected or for as long as DISRD is asserted "Low." This acts as a receive data mute upon LOSD function to prevent random noise from being misinterpreted as valid incoming data. When the SDEXT becomes active and the recovered clock is determined to be within ±500 ppm accuracy with respect to the local reference source, the clock recovery PLL will switch and lock back onto the incoming receive data stream and the lock detect output (LOCKDET_CDR) will go active. Table 5 specifies the Clock and Data Recovery Unit performance characteristics. 19 xr PRELIMINARY XRT91L82 2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER REV. P1.0.5 TABLE 5: CLOCK AND DATA RECOVERY UNIT PERFORMANCE NAME PARAMETER MIN TYP MAX UNITS REFDUTY Reference clock duty cycle 45 55 % REFTOL Reference clock frequency tolerance1 -20 +20 ppm OCLKJIT Clock output jitter generation with 155.52 MHz reference clock 5 7 mUIrms OCLKJIT Clock output jitter generation with 166.63 MHz reference clock 5 7 mUIrms TOLJIT Input jitter tolerance with 1 MHz < f < 20 MHz PRBS pattern 0.4 0.7 UI OCLKFREQ Frequency output 2.488 2.667 GHz OCLKDUTY Clock output duty cycle 45 55 % Jitter specification is defined using a 12kHz to 20MHz appropriate SONET/SDH filter. 1 Required to meet SONET output frequency stability requirements. 2.4 External Signal Detection XRT91L82 supports external Signal Detection (SDEXT). The external Signal Detect function is supported by the SDEXT input. This input is coming from the optical module through an output usually called “SD” or “FLAG” which indicates the lack or presence of optical power. Depending on the manufacturer of these devices, the polarity of this signal can be either active "Low" or active "High." The SDEXT and POLARITY inputs are Exclusive OR’ed to generate the internal Loss of Signal Detect (LOSD) declaration and Mute upon LOSD control signal. Whenever an external SD is absent, the XRT91L82 will automatically force the receive parallel data output to a logic state "0" for the entire duration that a LOSD condition is declared as well as update the status registers whenever the host mode serial microprocessor interface feature is active. This acts as a receive data mute upon LOSD function to prevent random noise from being misinterpreted as valid incoming data. Table 6 specifies SDEXT declaration polarity settings. TABLE 6: LOSD DECLARATION POLARITY SETTING SDEXT 0 0 1 1 RECEIVE PARALLEL DATA OUTPUT RXDO[15:0]P/N CLOCK AND DATA RECOVERY PLL REFERENCE LOCK Active Low. Optical signal presence indicated by SDEXT logic 0 input from optical module. LOSD not declared. Not Muted Hi-Spd Received Data Active High. Optical signal presence indicated by SDEXT logic 1 input from optical module. LOSD declared. Muted Local Reference Clock Active Low. Optical signal presence indicated by SDEXT logic 0 input from optical module. LOSD declared. Muted Local Reference Clock Active High. Optical signal presence indicated by SDEXT logic 1 input from optical module. LOSD not declared. Not Muted Hi-Spd Received Data POLARITY INTERNAL SIGNAL DETECT 0 1 0 1 20 xr XRT91L82 PRELIMINARY 2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER 2.5 REV. P1.0.5 Receive Serial Input to Parallel Output (SIPO) The SIPO is used to convert the 2.488/2.666 Gbps serial data input to 155.52/166.63 Mbps parallel data output which can interface to a SONET Framer/ASIC. The SIPO bit de-interleaves the serial data input into a 16-bit parallel output to RXDO[15:0]P/N. A simplified block diagram is shown in Figure 6. FIGURE 6. SIMPLIFIED BLOCK DIAGRAM OF SIPO 16-bit Parallel Data Output b03 b02 b01 b00 RXDOnP/N bn3 bn2 bn1 bn0 RXDOn+P/N bn+3 bn+2 bn+1 bn+0 RXDO15P/N b153 b152 b151 b150 RXPCLKOP/N 2.6 time (0) 2.488/2.666 Gbps SIPO RXDO0P/N b153 b143 b133 b123 b113 b103 b93 b70 b60 b50 b40 b30 b20 b10 b00 RXIP/N 155.52/ 166.63 MHz Receive Parallel Output Interface The 16-bit LVDS, Differential LVPECL or Single-Ended LVPECL 155.52/166.63 Mbps parallel data output of the receive path is used to interface to a SONET Framer/ASIC synchronized to the recovered clock. A simplified block diagram is shown in Figure 7. FIGURE 7. RECEIVE PARALLEL OUTPUT INTERFACE BLOCK RXDO[15:0]P/N 16 RXPCLKOP/N XRT91L82 STS-48/STM-16 Transceiver SONET Framer/ASIC DISRD DISRDCLK 21 SDEXT POLARITY xr PRELIMINARY XRT91L82 2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER REV. P1.0.5 2.7 Receive Parallel Interface LVDS Operation When operating the 16-bit Differential bus in LVDS mode, a 402Ω external resistor is needed across XRES1P and XRES1N to properly bias the RXDO[15:0]P/N and RXPCLKOP/N pins. Figure 8 shows the proper biasing resistor installed. FIGURE 8. LVDS EXTERNAL BIASING RESISTORS 402Ω +/- 1 % tolerance pin E14 2.8 XRES1P XRES1N pin F14 Parallel Receive Data Output Disable/Mute Upon LOSD The parallel receiver data outputs are automatically pulled "Low" during a LOSD condition to prevent data chattering. However, the user must select the proper SDEXT polarity for the optical module used. In addition, by pulling DISRD "Low", the receiver data outputs will be muted asynchronously or forced to a logic state of "0" regardless of the data input stream. 2.9 Parallel Receive Clock Output Disable Like DISRD, DISRDCLK is used to mute the parallel receiver clock output RXPCLKOP/N regardless of the data input stream. By pulling DISRDCLK "Low", the receiver clock output will be asynchronously muted whenever desired. 2.10 Receive Parallel Data Output Timing The receive parallel data output from the STS-48/STM-16 receiver will adhere to the setup and hold times shown in Figure 9 and Table 7. FIGURE 9. RECEIVE PARALLEL OUTPUT TIMING RXPCLKOP/N tRXPCLKO tRX_INV tRX_INV RXDO[15:0]P/N tRX_DEL SAMPLE WINDOW tRX_DEL TABLE 7: RECEIVE PARALLEL DATA AND CLOCK OUTPUT TIMING SPECIFICATIONS SYMBOL PARAMETER MIN TYP MAX UNITS tRXPCLKO Receive parallel clock output period (155.52 MHz non-FEC rate) 6.43 ns tRXPCLKO Receive parallel clock output period (166.63 MHz FEC rate) 6.00 ns tRX_INV RXPCLKOP/N "Low" to data invalid window 1000 ps tRX_DEL RXPCLKOP/N "Low" to data delay 900 ps RXDUTY RXPCLKOP/N Duty Cycle 55 % 45 22 xr XRT91L82 PRELIMINARY 2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER REV. P1.0.5 3.0 TRANSMIT SECTION The transmit section of the XRT91L82 accepts 16-bit parallel data and converts it to serial CML data output intented to interface to an optical module. It consists of a 16-bit parallel Differential LVPECL/LVDS, or SingleEnded LVPECL interface, a 16x9 FIFO, Parallel-to-Serial Converter, a clock multiplier unit (CMU), a Current Mode Logic (CML) differential line driver, and Loop Timing modes. The CML serial data output rate is 2.488/ 2.666 Gbps for STS-48 applications. The high frequency serial clock is synthesized by a PLL, which uses a low frequency clock as its input reference. In order to synchronize the data transfer process, the synthesized 2.488/2.666 GHz serial clock output is divided by sixteen and the 155.52/166.63 MHz clock is presented to the upstream device to be used as its timing source. 3.1 Transmit Parallel Interface The parallel data from an upstream device is presented to the XRT91L82 through a 16-bit Differential LVPECL/ LVDS/Single-Ended LVPECL parallel bus interface TXDI[15:0]P/N. The data is latched into a parallel input register on the rising edge of TXPCLKIP/N. If the SONET Framer/ASIC is synchronized to the same timing source as the XRT91L82, the transmit data and clock input can directly interface to the STS-48/STM-16 transceiver. However, if the SONET Framer/ASIC is synchronized to a separate crystal, the XRT91L82 has two clock output references that can be used to synchronize the SONET Framer/ASIC. TXPCLKOP/N is a 155.52/166.63 MHz Differential LVPECL/LVDS or Single-Ended LVPECL clock output source that is derived from the CMU synthesized clock. TXCLKO16P/N is a 155.52/166.63 MHz or 19.44/20.83 MHz Differential LVPECL/LVDS or Single-Ended LVPECL auxiliary clock output source that is also derived from the CMU sythensized clock. Either of these two clock output sources can be used to synchronize the SONET Framer/ ASIC to the XRT91L82. A simplified block diagram of the parallel interface is shown in Figure 10. FIGURE 10. TRANSMIT PARALLEL INPUT INTERFACE BLOCK TXDI[15:0]P/N XRT91L82 STS-48/STM-16 Transceiver 16 TXPCLKIP/N TXPCLKOP/N SONET Framer/ASIC TXCLKO16P/N TXCLKO16SEL 23 xr PRELIMINARY XRT91L82 2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER REV. P1.0.5 3.2 Transmit Parallel Data Input Timing When applying parallel data input to the transmitter, the setup and hold times should be followed as shown in Figure 11 and Table 8. Table 9 shows the parameters for TXPCLKOP/N clock output. FIGURE 11. TRANSMIT PARALLEL INPUT TIMING tTXPCLKO TXPCLKOP/N tTXPCLKI TXPCLKIP/N tTXDI_SU tTXDI_HD TXDI[15:0]P/N TABLE 8: TRANSMIT PARALLEL DATA AND CLOCK INPUT TIMING SPECIFICATION SYMBOL PARAMETER MIN TYP MAX UNITS tTXPCLKI Transmit parallel clock input period (155.52 MHz non-FEC rate) 6.43 ns tTXPCLKI Transmit parallel clock input period (166.63 MHz FEC rate) 6.00 ns tTXDI_SU TXPCLKIP/N "High" to data setup time 1000 ps tTXDI_HD TXPCLKIP/N "High" to data hold time 500 ps TXDUTY TXPCLKIP/N Duty Cycle 40 60 % MAX UNITS TABLE 9: TRANSMIT PARALLEL CLOCK OUTPUT TIMING SPECIFICATION SYMBOL PARAMETER MIN TYP tTXPCLKO Transmit parallel clock output period (155.52 MHz non-FEC rate) 6.43 ns tTXPCLKO Transmit parallel clock output period (166.63 MHz FEC rate) 6.00 ns TXDUTY TXPCLKOP/N Duty Cycle 3.3 45 55 % Transmit FIFO The Parallel Interface also includes a 16x9 FIFO that can be used to eliminate difficult timing issues between the input transmit clock and the clock derived from the CMU. The use of the FIFO permits the system to tolerate an arbitrary amount of delay and jitter between TXPCLKOP/N and TXPCLKIP/N. The FIFO can be initialized when FIFO_RST is asserted and held "High" for 2 cycles of the TXPCLKOP/N clock. When the FIFO_RST is de-asserted, it will take 8 to 10 TXPCLKOP/N cycles for the FIFO to flush out. Once the FIFO is centered, the delay between TXPCLKOP/N and TXPCLKIP/N can decrease or increase up to two periods of the low-speed clock. Should the delay exceed this amount, the read and write pointers will point to the same word in the FIFO resulting in a loss of transmitted data (FIFO overflow). In the event of a FIFO overflow, the FIFO control logic will initiate an OVERFLOW signal that can be used by an external controller to issue a FIFO RESET signal. 24 xr XRT91L82 PRELIMINARY 2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER REV. P1.0.5 In Host Mode, the transceiver under the control of the FIFO_AUTORST register bit can automatically recover from an overflow condition. When the FIFO_AUTORST register bit is set to a "High" level, once an overflow condition is detected, the chip will set the OVERFLOW pin to a high level and will automatically reset and center the FIFO. Figure 12 provides a detailed overview of the transmit FIFO in a system interface. FIGURE 12. TRANSMIT FIFO AND SYSTEM INTERFACE FIFO_AUTORST(Host Mode) Upstream Device XRT91L82 OVERFLOW RESET delay 16 x 9 FIFO TXPCLKIP/N Write Pointer TXDI[15:0]P/N 16 16 FIFO Control Read Pointer TXPCLKOP/N Div by 16 REF1CLKP/N 2.488/2.666 GHz PLL CMU REF2CLKP/N 3.4 FIFO Calibration Upon Power Up It is required that the FIFO_RST pin be pulled "High" for 2 TXPCLKOP/N cycles to flush out the FIFO after the device is powered on. If the FIFO experiences an Overflow condition, FIFO_RST can be used to manually reset the FIFO. In Host Mode, the STS-48 transceiver has an automatic FIFO reset register bit that will allow the FIFO to automatically reset upon an Overflow condition. FIFO_AUTORST register bit should be pulled "High" to enable the automatic FIFO reset function. 3.5 Transmit Parallel Input to Serial Output (PISO) The PISO is used to convert 155.52/166.63 Mbps parallel data input to 2.488/2.666 Gbps serial data output which can interface to an optical module. The PISO bit interleaves parallel data input into a serial bit stream taking the first bit from TXDI15P/N, then the first bit from TXDI14P/N, and so on as shown in Figure 13. FIGURE 13. SIMPLIFIED BLOCK DIAGRAM OF PISO 16-bit Parallel DIFF Input Data TXDI0P/N b07 b06 b05 b04 b03 b02 b01 b00 time (0) bn7 bn6 bn5 bn4 bn3 bn2 bn1 bn0 TXDIn+P/N bn+7 bn+6 bn+5 bn+4 bn+3 bn+2 bn+1 bn+0 TXDI15P/N b157 b156 b155 b154 b153 b152 b151 b150 TXPCLKIP/N 2.488/ 2.666 Gbps PISO TXDInP/N b150 b140 b130 b120 b110 b100 155.52/ 166.63 MHz 25 b77 b67 b57 b47 b37 b27 b17 b07 TXOP/N xr PRELIMINARY XRT91L82 2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER REV. P1.0.5 3.6 Clock Multiplier Unit (CMU) and Re-Timer The high-speed serial clock synthesized by the CMU is divided by 16 and is then presented to the upstream device as TXPCLKOP/N clock. The upstream device should use TXPCLKOP/N as its timing source. The upstream device then generates the TXPCLKIP/N clock that is phase aligned with the transmit data and provides it to the parallel interface of the transmitter. The data must meet setup and hold times with respect to TXPCLKIP/N. The XRT91L82 will latch TXDI[15:0]P/N on the rising edge of TXPCLKIP/N. The clock synthesizer uses a PLL to lock to the differential input reference clock REF1CLKP/N and REF2CLKP/N. REF1CLKP/N and/or REF2CLKP/N input can accept a clock from a Differential LVPECL crystal oscillator that has a frequency accuracy better than 20ppm in order for the TXSCLKOP/N frequency to have the accuracy required for SONET systems. It will then use this reference clock to generate the 2.488/2.666 GHz STS-48/ STM-16 serial clock output TXSCLKOP/N and in addition feed this high-speed synthesized clock to the PISO. The Retimer will then align the transmit serial data from the PISO with this 2.488/2.666 GHz synthesized clock to generate the output TXOP/N. Table 10 specifies the Clock Multiplier Unit performance characteristics. In Host Mode, the clock synthesizer can also be driven by an optional external VCXO for loop timed or local reference de-jitter applications. VCXO_IN can be connected to the output of a VCXO that can be configured to clean up the recovered received clock coming from CP_OUT in loop timing mode before being applied to the input of the transmit CMU as a reference clock. In addition, the internal phase/frequency detector and charge pump, combined with an external VCXO can alternately be used as a jitter attenuator to de-jitter a noisy system reference clock such as REF1CLKP/N or REF2CLKP/N prior to it being used to time the CMU. The following Section 3.7, “Loop Timing and Clock Control,” on page 26 illustrate the use of this method. TABLE 10: CLOCK MULTIPLIER UNIT PERFORMANCE NAME PARAMETER MIN TYP MAX UNITS REFDUTY Reference clock duty cycle 45 55 % REFTOL Reference clock frequency tolerance1 -20 +20 ppm REFSTS48 Reference clock jitter limits from 12 KHz to 20 MHz -61 dBC OCLKJIT Clock output jitter generation with 155.52 MHz reference clock 3.2 5.0 mUIrms OCLKJIT Clock output jitter generation with 166.63 MHz reference clock 3.2 5.0 mUIrms OCLKFREQ Frequency output 2.488 2.667 GHz OCLKDUTY Clock output duty cycle 45 55 % Jitter specification is defined using a 12kHz to 20MHz appropriate SONET/SDH filter. 1 3.7 Required to meet SONET output frequency stability requirements. Loop Timing and Clock Control Two types of loop timing are possible in the XRT91L82. In the Hardware mode, the loop timing (without an external VCXO) is controlled by the LOOPTM_NOJA pin. This mode is selected by asserting the LOOPTM_NOJA signal to a "High" level. When the loop timing mode is activated, the external local reference clock to the input of the CMU is replaced with the 1/16th of the highspeed recovered receive clock coming from the CDR. Under this condition both the transmit and receive sections are synchronized to the recovered receive clock. The normal looptime mode directly locks the CMU to the recovered receive clock with no external de-jittering. In Host Mode, loop timing performance can be further improved using an external VCXO-based PLL to clean up the jitter of the recovered receive clock. In this case the VCXO_SEL register bit should be set "High." By doing so, the CMU receives its reference clock signal from an external VCXO connected to the VCXO_IN input. The LOOPTM_JA register bit must also be set "High" in order to select the recovered receive clock as the reference source for the de-jitter PLL. In this state, the VCXO will be phase locked to the recovered receive clock through a narrowband loop filter. The use of the on-chip phase/frequency detector with charge pump and an external VCXO to remove the transmit jitter due to jitter in the recovered clock is shown in Figure 14. 26 xr XRT91L82 PRELIMINARY 2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER REV. P1.0.5 The on-chip phase/frequency detector can also be used to remove the jitter from a noisy reference signal that is applied to the REF1CLKP/N or REF2CLKP/N inputs. In this case the LOOPTM_NOJA register bit should be set "Low," the VCXO_SEL set "High," and the LOOPTM_JA register bit set "Low." In this configuration, the REF1CLKP/N or REF2CLKP/N CMU reference signal is used as the reference to the de-jitter PLL and the dejittered output of the phase locked VCXO is used as the timing reference to the CMU. Table 11 provides configuration for selecting the loop timing and reference de-jitter modes. TABLE 11: LOOP TIMING AND REFERENCE DE-JITTER CONFIGURATIONS VCXO_SEL (REGISTER BIT) LOOPTM_JA (REGISTER BIT) LOOPTM_NOJA (PIN/REGISTER BIT) CONFIGURATION ACTION 0 0 0 HARDWARE AND HOST Normal mode MODE 0 0 1 Loop timing without de-jitter VCXO HARDWARE AND HOST MODE 1 0 0 HOST MODE ONLY REF1CLKP/N or REF2CLKP/N reference de-jitter VCXO 1 1 0 HOST MODE ONLY Loop timing with de-jitter VCXO FIGURE 14. LOOP TIMING MODE USING AN EXTERNAL CLEANUP VCXO (HOST MODE ONLY) VCXO Loop Filter LOOPTM_JA Serial Microprocessor 0 LOOPTM_NOJA 1 Phase Detect Charge Pump RXCAP1N/ CPOUT 2.488/2.666GHz CMU 2.488/2.666GHz Retimer PISO TXOP TXON 1 MUX 1 0 MUX 0 VCXO_IN MUX MUX REF1CLKP REF1CLKN REF2CLKP REF2CLKN MUX VCXO_SEL REFREQSEL1 REFREQSEL0 LOOPTM_NOJA HOST/ HW LOCKDET_CMU Div by 16 or 32 RXIP RXIN CDR Data ALTFREQSEL ~ Clk XRT91L82 27 ~ xr PRELIMINARY XRT91L82 2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER REV. P1.0.5 3.8 External Loop Filter (Host Mode Only) During Host Mode operation, RXCAP1N becomes the charge pump output CP_OUT. As shown in Figure 14, the internal charge pump is used to drive an external loop filter and external VCXO. The charge pump current is fixed at 250uA. Figure 15 is a simplified block diagram of the external loop filter and recommended values. FIGURE 15. SIMPLIFIED DIAGRAM OF THE EXTERNAL LOOP FILTER CPOUT 4.02kΩ VCXO 300pF 1uF 3.9 Transmit Serial Output Control The 2.488/2.666 Gbps transmit serial output is avaliable on TXOP/N pins. The transmit serial output can be AC or DC coupled to an optical module or electrical interface. A simplified AC coupling block diagram is shown in Figure 16. FIGURE 16. TRANSMIT SERIAL OUTPUT INTERFACE BLOCK 0.1µF TXOP Optical Module TXON Optical Fiber 0.1µF XRT91L82 STS-48/ STM-16 Transceiver NOTE: Some optical modules integrate AC coupled capacitors within the module. If so, the external AC coupled capacitors are not necessary and can be excluded. The 2.488/2.666 Gbps high-speed differential CML output TXOP/N swing mode can be controlled through an pin called TXSWING. Setting this pin "Low" enables Low Swing Mode and lowers power consumption. Setting this pin "High" configures the transmit serial output for High Swing Mode. Figure 17 shows the CML differential voltage swing. TABLE 12: DIFFERENTIAL CML OUTPUT SWING PARAMETERS SIGNAL TYPE PARAMETER MIN (mV) MAX (mV) CML SERIAL VOLTAGE OUTPUT TXSWING SETTING (100Ω LINE TO LINE) Clock ∆VOUTDIFF 700 1400 Differential Voltage Swing High Swing Mode Clock ∆VOUTSE 350 700 Single-Ended Voltage Swing High Swing Mode Data ∆VOUTDIFF 800 1400 Differential Voltage Swing High Swing Mode Data ∆VOUTSE 400 700 Single-Ended Voltage Swing High Swing Mode 28 XRT91L82 PRELIMINARY 2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER xr REV. P1.0.5 TABLE 12: DIFFERENTIAL CML OUTPUT SWING PARAMETERS SIGNAL TYPE PARAMETER MIN (mV) MAX (mV) CML SERIAL VOLTAGE OUTPUT TXSWING SETTING (100Ω LINE TO LINE) Clock ∆VOUTDIFF 400 700 Differential Voltage Swing Low Swing Mode Clock ∆VOUTSE 200 350 Single-Ended Voltage Swing Low Swing Mode Data ∆VOUTDIFF 400 850 Differential Voltage Swing Low Swing Mode Data ∆VOUTSE 200 425 Single-Ended Voltage Swing Low Swing Mode FIGURE 17. CML DIFFERENTIAL VOLTAGE SWING V(+) VSINGLE V(-) V(+) - V(-) VDIFF = 2X VSINGLE 0V 29 xr PRELIMINARY XRT91L82 2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER REV. P1.0.5 4.0 DIAGNOSTIC FEATURES 4.1 Serial Remote Loopback RLOOPS_PRBSCLR is a dual function pin that serves as both serial remote loopback enable and PRBS error clear function. The serial remote loopback function is activated by setting RLOOPS_PRBSCLR "Low". When serial remote loopback is activated, the high-speed serial receive data from RXIP/N is presented at the highspeed transmit output TXOP/N, and the high-speed recovered clock is selected and presented to the highspeed transmit clock output TXSCLKOP/N. During serial remote loopback, the high-speed receive data (RXIP/ N) is also converted to parallel data and presented at the low-speed receive parallel interface RXDO[15:0]P/N. The recovered receive clock is also divided by 16 and presented at the low-speed clock output RXPCLKOP/N to synchronize the transfer of the 16-bit received parallel data. In PRBS Test Mode, serial remote loopback is not available when the PRBS generator and analyzer is enabled. This pin serve as the PRBS error clear (PRBSCLR) function to reset the PRBS_ERR error output indicator. A simplified block diagram of serial remote loopback is shown in Figure 18. FIGURE 18. SERIAL REMOTE LOOPBACK Serial Remote Loopback FIFO RX Parallel Output 4.2 PISO Re-Timer CML Output Drivers TX Serial Output SIPO CDR CML Input Drivers RX Serial Input Parallel Remote Loopback (Host Mode Only) RLOOPP controls a more comprehensive version of remote loopback that can also be used in conjunction with the de-jitter PLL that is phase locked to the recovered receive clock. In this mode, the received signal is processed by the CDR, and is sent through the serial to parallel converter. At this point, the 16-bit parallel data and clock are looped back to the transmit FIFO. Concurrently, if receive clock jitter attenuation is also employed, the received clock is divided down in frequency and presented to the input of the integrated phase/ frequency detector and is compared to the frequency of a VCXO that is connected to the VCXO_IN input. With the LOOPTM_JA configured to use the recovered receive clock as the reference and VCXO_SEL asserted, the VCXO is phase locked to the recovered receive clock. The de-jittered clock is then used to retime the transmitter, resulting in the re-transmission of the de-jittered received data out of TXOP/N. A FIFO reset using FIFO_RST should follow immediately after enabling/disabling parallel remote loopback. A simplified block diagram of parallel remote loopback is shown in Figure 19. FIGURE 19. PARALLEL REMOTE LOOPBACK Parallel Remote Loopback FIFO RX Parallel Output PISO Re-Timer CML Output Drivers TX Serial Output SIPO CDR CML Input MUX RX Serial Input 30 XRT91L82 PRELIMINARY 2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER 4.3 xr REV. P1.0.5 Digital Local Loopback The digital local loopback is activated when the DLOOP signal is set "Low." When digital local loopback is activated, the high-speed data from the output of the parallel to serial converter is looped back and presented to the high-speed input of the receiver serial to parallel converter. The CMU output is also looped back to the receive section and is used to synchronize the transfer of the data through the receiver. In Digital loopback mode the transmit data from the transmit parallel interface TXDI[15:0]P/N is serialized and presented to the high-speed transmit output TXOP/N along with the high-speed transmit clock which is generated from the clock multiplier unit and presented to the TXSCLKOP/N pins. A simplified block diagram of digital loopback is shown in Figure 20. FIGURE 20. DIGITAL LOOPBACK Digital Loopback TX Parallel Input RX Parallel Output FIFO PISO Re-Timer CML Output Drivers SIPO CDR CML Input Drivers 31 TX Serial Output xr PRELIMINARY XRT91L82 2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER REV. P1.0.5 4.4 SONET Jitter Requirements SONET equipment jitter requirements are specified for the following three types of jitter. The definitions of each of these types of jitter are given below. SONET equipment jitter requirements are specified for the following three types of jitter. 4.4.1 Jitter Tolerance: Jitter tolerance is defined as the peak-to-peak amplitude of sinusoidal jitter applied on the input OC-N equipment interface that causes an equivalent 1dB optical power penalty. OC-1/STS-1, OC-3/STS-3, OC-12/ STS-12 and OC-48/STS-48 category II SONET interfaces should tolerate, the input jitter applied according to the mask of Figure 21, with the corresponding parameters specified in the figure. FIGURE 21. JITTER TOLERANCE MASK A3 slope= -20dB/decade Input Jitter Amplitude (UIpp) slope= -20dB/decade A2 A1 f0 f1 f2 f4 f3 Jitter Frequency (Hz) OC-N/STS-N LEVEL F0 (HZ) F1 (HZ) F2 (HZ) F3 (HZ) F4 (HZ) A1 (UIPP) A2 (UIPP) A3 (UIPP) 1 10 30 300 2K 20K 0.15 1.5 15 3 10 30 300 6.5K 65K 0.15 1.5 15 12 10 30 300 25K 250K 0.15 1.5 15 48 10 600 6000 100K 1000K 0.15 1.5 15 32 XRT91L82 PRELIMINARY 2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER xr REV. P1.0.5 FIGURE 22. XRT91L82 MEASURED JITTER TOLERANCE IN LOOP TIMING MODE AT 2.488 GBPS STS-48/STM-16 TBD FIGURE 23. XRT91L82 MEASURED JITTER TOLERANCE IN LOOP TIMING MODE AT 2.666 GBPS FEC MODE TBD 4.4.2 Jitter Transfer Jitter transfer is defined as the ratio of the jitter on the output of STS-N to the jitter applied on the input of STS-N versus frequency. Jitter transfer is important in applications where the system is utilized in the looptimed mode, where the recovered clock is used as the source of the transmit clock. FIGURE 24. XRT91L82 MEASURED JITTER TRANSFER IN LOOP TIMING MODE AT 2.488 GBPS STS-48/STM-16 TBD FIGURE 25. XRT91L82 MEASURED JITTER TRANSFER IN LOOP TIMING MODE AT 2.666 GBPS FEC MODE TBD 33 xr REV. P1.0.5 4.4.3 PRELIMINARY XRT91L82 2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER Jitter Generation Jitter generation is defined as the amount of jitter at the STS-N output in the absence of applied input jitter. The Bellcore and ITU requirement for this type jitter is 0.01UI rms measured with a specific band-pass filter. For more information on these specifications refer to Bellcore TR-NWT-000253 sections 5.6.2-5 and GR-253CORE section 5.6. FIGURE 26. XRT91L82 MEASURED ELECTRICAL PHASE NOISE TRANSMIT JITTER GENERATION AT 2.488 GBPS TBD FIGURE 27. XRT91L82 MEASURED ELECTRICAL PHASE NOISE TRANSMIT JITTER GENERATION AT 2.666 GBPS TBD 34 xr XRT91L82 PRELIMINARY 2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER REV. P1.0.5 5.0 SERIAL MICROPROCESSOR INTERFACE BLOCK The serial microprocessor uses a standard 3-pin serial port with CS, SCLK, and SDI for programming the transceiver. Optional pins such as SDO, INT, and RESET allow the ability to read back contents of the registers, monitor the transceiver via an interrupt pin, and reset the transceiver to its default configuration by pulling reset "Low" for more than 30ns. A simplified block diagram of the Serial Microprocessor is shown in Figure 28. FIGURE 28. SIMPLIFIED BLOCK DIAGRAM OF THE SERIAL MICROPROCESSOR INTERFACE SDO CS SCLK INT SDI Serial Microprocessor Interface HW/Host RESET 5.1 SERIAL TIMING INFORMATION The serial port requires 16 bits of data applied to the SDI (Serial Data Input) pin. The Serial Microprocessor samples SDI on the rising edge of SCLK (Serial Clock Input). The data is not latched into the device until all 16 bits of serial data have been sampled. A timing diagram of the Serial Microprocessor is shown in Figure 29. FIGURE 29. TIMING DIAGRAM FOR THE SERIAL MICROPROCESSOR INTERFACE CS 25nS 50nS SCLK 1 SDI R/W SDO 2 A0 3 A1 4 A2 5 A3 6 A4 7 9 8 A5 X High-Z 10 11 12 13 14 15 16 D0 D1 D2 D3 D4 D5 D6 D7 D0 D1 D2 D3 D4 D5 D6 D7 High-Z NOTE: The serial microprocessor interface does NOT support "burst write" or "burst read" operations. Chip Select (active "Low") must be de-asserted at the end of every single write or single read operation. 35 xr REV. P1.0.5 PRELIMINARY XRT91L82 2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER 5.2 16-BIT SERIAL DATA INPUT DESCRITPTION The serial data input is sampled on the rising edge of SCLK. In readback mode, the serial data output is updated on the falling edge of SCLK. The serial data must be applied to the transceiver LSB first. The 16 bits of serial data are described below. 5.2.1 R/W (SCLK1) The first serial bit applied to the transceiver informs the microprocessor that a Read or Write operation is desired. If the R/W bit is set to “0”, the microprocessor is configured for a Write operation. If the R/W bit is set to “1”, the microprocessor is configured for a Read operation. 5.2.2 A[5:0] (SCLK2 - SCLK7) The next 6 SCLK cycles are used to provide the address to which a Read or Write operation will occur. A0 (LSB) must be sent to the transceiver first followed by A1 and so forth until all 6 address bits have been sampled by SCLK. 5.2.3 X (Dummy Bit SCLK8) The dummy bit sampled by SCLK8 is used to allow sufficient time for the serial data output pin to update data if the readback mode is selected by setting R/W = “1”. Therefore, the state of this bit is ignored and can hold either “0” or “1” during both Read and Write operations. 5.2.4 D[7:0] (SCLK9 - SCLK16) The next 8 SCLK cycles are used to provide the data to be written into the internal register chosen by the address bits. D0 (LSB) must be sent to the transceiver first followed by D1 and so forth until all 8 data bits have been sampled by SCLK. Once 16 SCLK cycles have been complete, the transceiver holds the data until CS is pulled “High” whereby, the serial microprocessor latches the data into the selected internal register. 5.3 8-BIT SERIAL DATA OUTPUT DESCRIPTION The serial data output is updated on the falling edge of SCLK9 - SCLK16 if R/W is set to “1”. D0 (LSB) is provided on SCLK9 to the SDO pin first followed by D1 and so forth until all 8 data bits have been updated. The SDO pin allows the user to read the contents stored in individual registers by providing the desired address on the SDI pin during the Read cycle. 36 xr XRT91L82 PRELIMINARY 2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER REV. P1.0.5 6.0 REGISTER MAP AND BIT DESCRIPTIONS TABLE 13: MICROPROCESSOR REGISTER MAP REG ADDR TYPE D7 D6 D5 D4 D3 D2 D1 D0 Control Registers (0x00h - 0x3Fh) 0 0x00 R/W Reserved PRBSLIE PRBSEIE VCXOIE LOSIE CDRIE CMUIE FIFOIE 1 0x01 RUR Reserved PRBSLIS PRBSEIS VCXOIS LOSIS CDRIS CMUIS FIFOIS 2 0x02 RO Reserved PRBS_LOCK PRBS_ERR VCXOD LOSD CDRD CMUD FIFOD 3 0x03 R/W Reserved Reserved Reserved Reserved Reserved Reserved FIFO_AUTORST FIFO_RST 4 0x04 R/W Reserved Reserved Reserved Reserved DISRD DISRDCLK TXSCLKOFF CDRLCKREF 5 0x05 R/W Reserved Reserved PRBS_INV PRBS_EN Reserved DLOOP RLOOPS RLOOPP 6 0x06 R/W VCXOLKEN LOOPBW Reserved Reserved Reserved VCXO_SEL LOOPTM_JA LOOPTM_ NOJA 7 0x07 R/W REFREQSEL 1 TXCLK016 SEL INTERM SEREFDIS TXSWING POLARITY 8 0x08 Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved 9 0x09 Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved 10 0x0A Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved 11 0x0B Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved 0x0C - 0x3B R/W Reserved REFREQSEL ALTFREQSEL 0 60 0x3C RO Device ID MSB (See Bit Description) 61 0x3D RO Device ID LSB (See Bit Description) 63 0x3F RO Revision ID (See Bit Description) 37 xr REV. P1.0.5 PRELIMINARY XRT91L82 2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER TABLE 14: MICROPROCESSOR REGISTER 0X00H BIT DESCRIPTION INTERRUPT ENABLE CONTROL REGISTER (0X00H) BIT NAME FUNCTION D7 Reserved This Register Bit is Not Used D6 PRBSLIE 223-1 PRBS Pattern Lock Interrupt Enable "0" = Masks the PRBS Pattern Lock interrupt generation "1" = Enables Interrupt generation Register Type Default Value (HW reset) X X R/W 0 R/W 0 R/W 0 NOTE: PRBS_EN must be enabled for this bit to have functional meaning. D5 PRBSEIE 223-1 PRBS Pattern Error Interrupt Enable "0" = Masks the PRBS error interrupt generation "1" = Enables Interrupt generation NOTE: PRBS_EN must be enabled for this bit to have functional meaning. D4 VCXOIE Voltage Controlled External Oscillator Lock Interrupt Enable "0" = Masks the VCXO Lock interrupt generation "1" = Enables Interrupt generation NOTE: VCXOLKEN must be enabled for this bit to have functional meaning. D3 LOSIE Loss of Signal Interrupt Enable "0" = Masks the LOS interrupt generation "1" = Enables Interrupt generation R/W 0 D2 CDRIE Clock and Data Recovery Lock Interrupt Enable "0" = Masks the CDR Lock interrupt generation "1" = Enables Interrupt generation R/W 0 D1 CMUIE Clock Multiplier Unit Lock Interrupt Enable "0" = Masks the CMU Lock interrupt generation "1" = Enables Interrupt generation R/W 0 D0 FIFOIE FIFO Overflow Interrupt Enable "0" = Masks the FIFO Overflow interrupt generation "1" = Enables Interrupt generation R/W 0 38 xr XRT91L82 PRELIMINARY 2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER REV. P1.0.5 TABLE 15: MICROPROCESSOR REGISTER 0X01H BIT DESCRIPTION INTERRUPT STATUS CONTROL REGISTER (0X01H) BIT NAME FUNCTION D7 Reserved This Register Bit is Not Used D6 PRBSLIS 223-1 PRBS Pattern Lock Interrupt Status An external interrupt will not occur unless the PRBSLIE is set to "1" in the channel register 0x00h. "0" = No Change "1" = Change in PRBS Lock Status Occurred Register Type Default Value (HW reset) X X RUR 0 RUR 0 RUR 0 NOTE: PRBS_EN must be enabled for this bit to have functional meaning. D5 PRBSEIS 223-1 PRBS Pattern Error Detect Interrupt Status Indicates an error condition has occurred in the validation of generated PRBS pattern. "0" = Un-erred transmission and reception of PRBS pattern. "1" = PRBS pattern validation error has Occured NOTE: PRBS_EN must be enabled for this bit to have functional meaning. D4 VCXOIS Voltage Controlled External Oscillator Lock Interrupt Status An external interrupt will not occur unless the VCXOIE is set to "1" in the channel register 0x00h. "0" = No Change "1" = Change in VCXO Lock Status Occurred NOTE: VCXOLKEN must be enabled for this bit to have functional meaning. D3 LOSIS Loss of Signal Interrupt Status An external interrupt will not occur unless the RLOSIE is set to "1" in the channel register 0x00h. "0" = No Change "1" = Change in LOS Status Occurred RUR 0 D2 CDRIS Clock and Data Recovery Lock Interrupt Status An external interrupt will not occur unless the CDRIE is set to "1" in the channel register 0x00h. "0" = No Change "1" = Change in CDR Lock Status Occurred RUR 0 D1 CMUIS Clock Multiplier Unit Lock Interrupt Status An external interrupt will not occur unless the CMUIE is set to "1" in the channel register 0x00h. "0" = No Change "1" = Change in CMU Lock Status Occurred RUR 0 D0 FIFOIS FIFO Overflow Interrupt Status An external interrupt will not occur unless the FIFOIE is set to "1" in the channel register 0x00h. "0" = No Change "1" = Change in FIFO Overflow Status Occurred RUR 0 39 xr REV. P1.0.5 PRELIMINARY XRT91L82 2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER TABLE 16: MICROPROCESSOR REGISTER 0X02H BIT DESCRIPTION STATUS CONTROL REGISTER (0X02H) BIT NAME D7 Reserved FUNCTION This Register Bit is Not Used Register Type Default Value (HW reset) X X D6 PRBS_LOCK 223-1 PRBS Pattern Lock Detection Indicates that current state condition of the PRBS pattern analyzer when the PRBS pattern generator is enabled. "0" = PRBS pattern analyzer currently Out of Lock "1" = PRBS pattern analyzer currently Locked RO 0 D5 PRBS_ERR 223-1 PRBS Pattern Error Detection Indicates an error condition is occuring in the validation of generated PRBS pattern. "0" = Un-erred transmission and reception of PRBS pattern. "1" = PRBS pattern validation error condition is present. RO 0 RO 0 NOTE: PRBS_EN must be enabled for this bit to have functional meaning. D4 VCXOD Voltage Controlled External Oscillator Lock Detection The VCXOD is used to indicate whether the internal clock reference is locked to an external VCO. "0" = VCXO currently not Locked "1" = VCXO Locked NOTE: VCXOLKEN must be enabled for this bit to have functional meaning. D3 LOSD Loss of Signal Detection The LOSD indicates the Loss of Signal Detect activity. "0" = No Alarm "1" = A LOSD condition is present RO 0 D2 CDRD Clock and Data Recovery Lock Detection The CDRD is used to indicate that the CDR is locked. "0" = CDR Out of Lock "1" = CDR Locked RO 0 D1 CMUD Clock Multiplier Unit Lock Detection The CMUD is used to indicate that the CMU is locked. "0" = CMU Out of Lock "1" = CMU Locked RO 0 D0 FIFOD FIFO Overflow Detection The FIFOD indicates that the FIFO is experiencing an overflow condition. "0" = No Alarm "1" = A FIFO Overflow condition is present RO 0 40 xr XRT91L82 PRELIMINARY 2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER REV. P1.0.5 TABLE 17: MICROPROCESSOR REGISTER 0X03H BIT DESCRIPTION FIFO CONTROL REGISTER (0X03H) Register Type Default Value (HW reset) This Register Bit is Not Used X X Reserved This Register Bit is Not Used X X D5 Reserved This Register Bit is Not Used X X D4 Reserved This Register Bit is Not Used X X D3 Reserved This Register Bit is Not Used X X D2 Reserved This Register Bit is Not Used X X D1 FIFO_ AUTORST Automatic FIFO Overflow Reset If this bit is set to "1", the STS-48 transceiver will automatically flush the FIFO upon an overflow condition. Upon power-up, the FIFO should be manually reset by setting FIFO_RST to "1" for a minimum of 2 TXPCLKOP/N cycles. "0" = Manual FIFO reset required for Overflow Conditions "1" = Automatically resets FIFO upon Overflow Detection R/W 0 D0 FIFO_RST Manual FIFO Reset FIFORST should be set to "1" for a minimum of 2 TXPCLKOP/N cycles during power-up and manual FIFO reset in order to flush out the FIFO. After the FIFORST bit is returned "Low," it will take 8 to 10 TXPCLKOP/N cycles for the FIFO to flush out. Upon an interrupt indication that the FIFO has an overflow condition, this bit is used to reset or flush out the FIFO. "0" = Normal Operation "1" = Manual FIFO Reset R/W 0 BIT NAME D7 Reserved D6 FUNCTION NOTE: To automatically reset the FIFO, see the FIFO_AUTORST bit. 41 xr REV. P1.0.5 PRELIMINARY XRT91L82 2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER TABLE 18: MICROPROCESSOR REGISTER 0X04H BIT DESCRIPTION OUTPUT CONTROL REGISTER (0X04H) Register Type Default Value (HW reset) This Register Bit is Not Used X X Reserved This Register Bit is Not Used X X D5 Reserved This Register Bit is Not Used X X D4 Reserved This Register Bit is Not Used X X D3 DISRD Receive Parallel Data Output Disable If this bit is set to "0", the 16-bit parallel receive data output will asynchronously mute. "0" = Forces RXDO[15:0]P/N to a logic state "0" "1" = Normal Mode R/W 1 D2 DISRDCLK Receive Parallel Clock Output Disable This bit is used to asynchronously control the activity of the parallel receive clock output. "0" = Forces RXPCLKOP/N to a logic state of "0" "1" = Normal Mode R/W 1 D1 TXSCLKOOFF Transmit Serial Clock Output Tristate This bit is used to control the activity of the 2.488/2.666 GHz differential serial clock output. Tristating TXSCLKOP/N output reduces power consumption. "0" = TXSCLKOP/N output Enabled "1" = TXSCLKOP/N output Tristated R/W 1 D0 CDRLCKREF CDR’s Recovered High-speed Serial Clock Reference Controls CDR’s operation. "0" = Forced to lock to CDR PLL reference training clock "1" = Normal Operation (Locked to incoming serial data) R/W 1 BIT NAME D7 Reserved D6 FUNCTION 42 xr XRT91L82 PRELIMINARY 2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER REV. P1.0.5 TABLE 19: MICROPROCESSOR REGISTER 0X05H BIT DESCRIPTION DIAGNOSTIC CONTROL REGISTER (0X05H) BIT NAME D7 Reserved D6 Reserved Register Type Default Value (HW reset) This Register Bit is Not Used X X This Register Bit is Not Used X X FUNCTION D5 PRBS_INV 223-1 PRBS Pattern Invert This bit will invert each of the Pseudo Random Binary Sequence pattern bit from "0" to "1" and from "1" to "0." "0" = Normal Operation "1" = PRBS bit patterns inverted. R/W 0 D4 PRBS_EN R/W 0 X X R/W 1 223-1 PRBS TEST Pattern Enable 223-1 Generates Pseudo Random Binary Sequence test patterns and analyzes in the receiving block for correct sequence pattern. "0" = Normal Mode "1" = PRBS pattern generator and analyzer Enabled. NOTE: D3 Reserved D2 DLOOP A Local Loopback of some type such as Digital Local Loopback or an optical cable loopback is expected to be used in conjunction with PRBS_EN in order for the PRBS analyzer to receive the PRBS pattern. This Register Bit is Not Used Digital Local Loopback Digital local loopback allows the transmit input pins to be looped back to the receive output pins for local diagnostics. The transmit serial data output is valid during the digital loopback. "0" = Enable Digital Local Loopback "1" = Disabled NOTE: RLOOPS and RLOOPP should be disabled when DLOOP is enabled. 43 xr REV. P1.0.5 PRELIMINARY XRT91L82 2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER DIAGNOSTIC CONTROL REGISTER (0X05H) BIT NAME FUNCTION D1 RLOOPS Serial Remote Loopback Serial remote loopback allows the receive serial input pins to be looped back to the transmit serial output pins for remote diagnostics. The receive data output is valid during a serial remote loopback. "0" = Enable Remote Serial Loopback "1" = Disabled Register Type Default Value (HW reset) R/W 1 R/W 1 NOTE: DLOOP and RLOOPP should be disabled when RLOOPS is enabled. D0 RLOOPP Parallel Remote Loopback Parallel remote loopback has the same affect as the serial remote loopback, except that the data input is allowed to pass through the SIPO before it’s looped back to the transmit path, wherein it passes through the transmit FIFO, through the PISO, and back out the transmit serial output. The receive data output is valid during a parallel remote loopback. "0" = Enable Remote Parallel Loopback "1" = Disabled NOTE: DLOOP and RLOOPS should be disabled when RLOOPP is enabled. The internal FIFO should also be flushed using FIFO_RST when parallel remote loopback is enabled/ disabled. 44 xr XRT91L82 PRELIMINARY 2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER REV. P1.0.5 TABLE 20: MICROPROCESSOR REGISTER 0X06H BIT DESCRIPTION TIMING CONTROL REGISTER (0X06H) Register Type Default Value (HW reset) De-Jitter PLL Lock Detect Enable This bit enables the VCXO_IN input lock detect circuit to be active. "0" = VCXO Lock Detect Disabled "1" = VCXO Lock Detect Enabled R/W 0 LOOPBW CMU Loop Band Width Select This bit is used to select the bandwidth of the clock multiplier unit of the transmit path to a narrow or wide band. Use Wide Band for clean reference signals and Narrow Band for noisy references. "0" = Wide Band (4x) "1" = Narrow Band (1x) R/W 0 D5 Reserved This Register Bit is Not Used X X D4 Reserved This Register Bit is Not Used X X D3 Reserved This Register Bit is Not Used X X D2 VCXO_SEL VCXO De-Jitter Select This bit selects either the normal REF1CLKP/N and REF2CLKP/N or the de-jitter VCXO_IN as a reference clock to the CMU. "0" = Normal REF1CLKP/N and/or REF2CLKP/N Mode "1" = De-Jitter VCXO Mode R/W 0 D1 LOOPTM_JA Loop Timing With Jitter Attenuation R/W 0 R/W 0 BIT NAME FUNCTION D7 VCXOLKEN D6 The LOOPTM_JA bit must be set to "1" in order to select the recovered receive clock as the reference source for the de-jitter PLL. "0" = Disabled "1" = Loop timing with de-jitter PLL Activated D0 LOOPTM_ NOJA Loop Timing With No Jitter Attenuation When the loop timing mode is activated, the external local reference clock input to the CMU is replaced with the 1/16th or 1/32nd (ALTFREQSEL option available in Host Mode) of the high-speed recovered receive clock coming from the CDR. "0" = Disabled "1" = Loop timing Activated 45 xr PRELIMINARY XRT91L82 2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER REV. P1.0.5 TABLE 21: MICROPROCESSOR REGISTER 0X07H BIT DESCRIPTION CONFIGURATION CONTROL REGISTER (0X07H) BIT NAME D7 REFREQSEL1 FUNCTION Input Reference Frequency Select This bit is used to select the clock input reference. REFREQSEL [1:0] CMU CDR REFERENCE FREQUENCY REFERENCE FREQUENCY 00 155.52 MHz present on 155.52 MHz present on REF1CLK REF1CLK REF2CLK not used REF2CLK not used 01 155.52 MHz present on 166.63 MHz present on REF1CLK REF2CLK 10 166.63 MHz present on 155.52 MHz present on REF2CLK REF1CLK 11 166.63 MHz present on 166.63 MHz present on REF2CLK REF2CLK REF1CLK not used REF1CLK not used Register Type Default Value (HW reset) R/W 0 R/W 0 Note: Non-FEC transmission and/or reception modes require 155.52 MHz clock reference. FEC transmission and/or reception mode requires 166.63 MHz clock reference. D6 REFREQSEL0 Input Reference Frequency Select This bit is used to select the clock input reference. REFREQSEL [1:0] CMU CDR REFERENCE FREQUENCY REFERENCE FREQUENCY 00 155.52 MHz present on 155.52 MHz present on REF1CLK REF1CLK REF2CLK not used REF2CLK not used 01 155.52 MHz present on 166.63 MHz present on REF1CLK REF2CLK 10 166.63 MHz present on 155.52 MHz present on REF2CLK REF1CLK 11 166.63 MHz present on 166.63 MHz present on REF2CLK REF2CLK REF1CLK not used REF1CLK not used Note: Non-FEC transmission and/or reception modes require 155.52 MHz clock reference. FEC transmission and/or reception mode requires 166.63 MHz clock reference. 46 xr XRT91L82 PRELIMINARY 2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER REV. P1.0.5 CONFIGURATION CONTROL REGISTER (0X07H) BIT NAME FUNCTION D5 ALTFREQSEL Alternate Low Reference Frequency Select (77.76/83.31 MHz) This pin is used to select and support lower frequency settings on REF1CLKP/N and REF2CLKP/N reference clock inputs. When using a VCXO, this pin should also be set accordingly to the VCXO frequency output. "0" = 77.76/83.31 MHz reference frequency support "1" = 155.52/166.63 MHz reference frequency support Register Type Default Value (HW reset) R/W 1 R/W 0 If ALTFREQSEL = "0" REFREQSEL [1:0] CMU CDR REFERENCE FREQUENCY REFERENCE FREQUENCY 00 77.76 MHz present on REF1CLK REF2CLK not used 77.76 MHz present on REF1CLK REF2CLK not used 01 77.76 MHz present on REF1CLK 83.31 MHz present on REF2CLK 10 83.31 MHz present on REF2CLK 77.76 MHz present on REF1CLK 11 83.31 MHz present on REF2CLK REF1CLK not used 83.31 MHz present on REF2CLK REF1CLK not used Note: Non-FEC transmission and/or reception modes require 77.76 MHz clock reference. FEC transmission and/or reception mode requires 83.31 MHz clock reference. If ALTFREQSEL = "1" REFREQSEL [1:0] CMU CDR REFERENCE FREQUENCY REFERENCE FREQUENCY 00 155.52 MHz present on 155.52 MHz present on REF1CLK REF1CLK REF2CLK not used REF2CLK not used 01 155.52 MHz present on 166.63 MHz present on REF1CLK REF2CLK 10 166.63 MHz present on 155.52 MHz present on REF2CLK REF1CLK 11 166.63 MHz present on 166.63 MHz present on REF2CLK REF2CLK REF1CLK not used REF1CLK not used Note: Non-FEC transmission and/or reception modes require 155.52 MHz clock reference. FEC transmission and/or reception mode requires 166.63 MHz clock reference. D4 TXCLKO16SEL Auxiliary Clock Output Select This bit is used to select the auxiliary clock frequency output. "0" = TXCLKO16P/N outputs 155.52/166.63 MHz "1" = TXCLKO16P/N outputs 19.44/20.83 MHz 47 xr REV. P1.0.5 PRELIMINARY XRT91L82 2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER CONFIGURATION CONTROL REGISTER (0X07H) Register Type Default Value (HW reset) Transmit Parallel Bus Input Internal Termination Provides 100Ω line-to-line internal termination to TXDI[15:0]P/N and TXPCLKIP/N. "Low" = Disabled "High" = TXDI[15:0]P/N and TXPCLKIP/N internally terminated. R/W 0 SEREFDIS SE_REF Power down Control Powers down SE_REF and reduces power consumption. "0" = SE_REF Enabled "1" = SE_REF Disabled R/W 1 D1 TXSWING Serial CML Optical Transceiver Swing Select This bit is used to select the output swing of the high-speed CML interface to the optical transceiver. "0" = Low Swing Mode CML Output Selected "1" = High Swing Mode CML Output Selected See Table 12 in “Section 3.9, Transmit Serial Output Control” on page 28. R/W 1 D0 POLARITY Polarity for SDEXT Input R/W 1 Register Type Default Value (HW reset) RO 1 0 0 0 0 0 0 0 BIT NAME D3 INTERM D2 FUNCTION Controls the Signal Detect polarity convention of SDEXT. "0" = SDEXT is active "Low" "1" = SDEXT is active "High" TABLE 22: MICROPROCESSOR REGISTER 0X3CH BIT DESCRIPTION DEVICE "ID" REGISTER (0X3CH) BIT D7 D6 D5 D4 D3 D2 D1 D0 NAME FUNCTION Device "ID" The device "ID" of the XRT91L82 LIU is 0x8003h. Along with the revision "ID", the device "ID" is used to enable software to identify MSB the silicon adding flexibility for system control and debug. 48 XRT91L82 PRELIMINARY 2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER xr REV. P1.0.5 TABLE 23: MICROPROCESSOR REGISTER 0X3DH BIT DESCRIPTION DEVICE "ID" REGISTER (0X3DH) BIT D7 D6 D5 D4 D3 D2 D1 D0 NAME FUNCTION Device "ID" The device "ID" of the XRT91L82 LIU is 0x8003h. Along with the revision "ID", the device "ID" is used to enable software to identify LSB the silicon adding flexibility for system control and debug. Register Type Default Value (HW reset) RO 0 0 0 0 0 0 1 1 Register Type Default Value (HW reset) RO This byte shows the revision of the device. TABLE 24: MICROPROCESSOR REGISTER 0X3FH BIT DESCRIPTION REVISION "ID" REGISTER (0X3FH) BIT NAME FUNCTION D7 D6 D5 D4 D3 D2 D1 D0 Revision "ID" The revision "ID" of the XRT91L82 LIU is used to enable software to identify which revision of silicon is currently being tested. The revision "ID" for the first revision of silicon (Revision A) will be 0x01h. 49 xr PRELIMINARY XRT91L82 2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER REV. P1.0.5 7.0 ELECTRICAL CHARACTERISTICS ABSOLUTE MAXIMUM RATINGS Thermal Resistance of STBGA Package....ΘjA = 25°C/W Operating Temperature Range.................-40°C t o 85°C Thermal Resistance of STBGA Package....ΘjC = 10°C/W Case Temperature under bias..................-55°C to 125°C ESD Protection (HBM)..........................................>2000V Storage Temperature ...............................-65°C to 150°C ABSOLUTE MAXIMUM POWER AND INPUT LOGIC SIGNALS SYMBOL TYPE PARAMETER MIN VDD1.8 1.8V Digital and Analog Power Supplies VDD_IO TYP MAX UNITS -0.5 3.6 V 3.3V LVPECL/LVDS Input Power Supply -0.5 6.0 V LVPECL DC logic signal input voltage -0.5 VDD_IO +0.5 V LVDS DC logic signal input voltage -0.5 VDD_IO +0.5 V LVTTL/ LVCMOS DC logic signal input voltage -0.5 5.5 V LVCMOS DC logic signal output voltage -0.5 VDD_IO +0.5 V LVPECL Input current -100 100 mA LVTTL/ LVCMOS Input current -100 100 mA NOTE: Stresses listed under Absolute Maximum Power and I/O ratings may be applied to devices one at a time without causing permanent damage. Functionality at or above the values listed is not implied. Exposure to these values for extended periods will severely affect device reliability. POWER AND CURRENT DC ELECTRICAL CHARACTERISTICS SYMBOL TYPE PARAMETER MIN TYP MAX UNITS CONDITIONS VDD1.8 CML and CMOS Power Supply Voltage 1.710 1.8 1.890 V AVDDTX Transmit Power Supply Voltage (AVDD_TX) 1.710 1.8 1.890 V AVDDRX Receiver Power Supply Voltage (AVDD_RX) 1.710 1.8 1.890 V VDD_IO LVPECL or LVDS Input and Digital I/O Power Supply Voltage 3.135 3.3 3.465 V 1.8V Power Supply Noise Rejection Ratio 50 mVP-P 6 KHz 2 MHz 3.3V Power Supply Noise Rejection Ratio 50 mVP-P 6 KHz 2 MHz IDD_1.8 1.8V Total Power Supply Current TBD mA IDD_IO 3.3V Total Power Supply Current TBD mA 50 xr XRT91L82 PRELIMINARY 2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER REV. P1.0.5 POWER AND CURRENT DC ELECTRICAL CHARACTERISTICS SYMBOL TYPE PARAMETER MIN TYP MAX UNITS CONDITIONS PLVDS Total Power Dissipation 500 700 mW LVDS PLVPECL Total Power Dissipation 1400 1700 mW LVPECL LVPECL LOGIC SIGNAL DC ELECTRICAL CHARACTERISTICS Test Condition: TA = 25°C, VDD 1.8 = 1.8V + 5%, VDD_IO = 3.3V + 5%, VDD_IO= 3.3V + 5% unless otherwise specified SYMBOL TYPE PARAMETER VOH LVPECL Output High Voltage VOL LVPECL Output Low Voltage VODIFF LVPECL Output Differential Voltage Swing VOSINGLE LVPECL Output Single-Ended Voltage Swing VIH LVPECL VIL MIN TYP MAX UNITS CONDITIONS VDD_IO -1.15 VDD_IO -0.735 V VDD_IO -1.95 VDD_IO -1.495 V 1 2 V 0.5 1 V Single-Ended Input High Voltage VDD_IO - 1.2 VDD_IO - 0.7 V Differential and Single-Ended LVPECL Input Low Voltage VDD_IO - 2.0 VDD_IO - 1.40 V Differential and Single-Ended VIDIFF LVPECL Input Differential Voltage 0.4 2.4 V Differential Mode. See Figure 17 VISINGLE LVPECL Input Single-Ended Voltage Swing 0.2 1.2 V Differential Mode. See Figure 17 VISE LVPECL Input Single-Ended Voltage Swing 0.4 (+/- 0.2V w.r.t. VBB100K) V Single-Ended Mode See Figure 17 LVDS LOGIC SIGNAL DC ELECTRICAL CHARACTERISTICS Test Condition: TA = 25°C, VDD 1.8 = 1.8V + 5%, VDD_IO = 3.3V + 5% unless otherwise specified SYMBOL TYPE PARAMETER MIN VOH LVDS Output High Voltage VOL LVDS Output Low Voltage 810 VODIFF LVDS Output Differential Voltage Swing 450 VOSINGLE LVDS Output Single-Ended Voltage Swing 225 VIH LVDS Input High Voltage 51 TYP MAX UNITS CONDITIONS 1680 mV 100 Ω line - line mV 100 Ω line - line 1320 mV 100 Ω line - line 660 mV 100 Ω line - line 2400 mV xr PRELIMINARY XRT91L82 2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER REV. P1.0.5 Test Condition: TA = 25°C, VDD 1.8 = 1.8V + 5%, VDD_IO = 3.3V + 5% unless otherwise specified SYMBOL TYPE PARAMETER MIN TYP MAX UNITS VIL LVDS Input Low Voltage 800 VIDIFF LVDS Input Differential Voltage Swing 200 1300 mV VISINGLE LVDS Input Single-Ended Voltage Swing 100 650 mV CONDITIONS mV LVTTL/LVCMOS SIGNAL DC ELECTRICAL CHARACTERISTICS Test Condition: TA = 25°C, VDD 1.8 = 1.8V + 5%, VDD_IO = 3.3V + 5% unless otherwise specified SYMBOL PARAMETER MIN MAX UNITS CONDITIONS VOH LVCMOS Output High Voltage 2.93 VDD_IO V IOH = -1.0mA VOL LVCMOS Output Low Voltage 0 0.2 V IOH = 1.0mA VIH LVTTL/ Input High Voltage LVCMOS 2.2 3.3 V VIL LVTTL/ Input Low Voltage LVCMOS -0.5 0.7 V IIH LVTTL/ Input High Current LVCMOS 500 µA IIL TYPE TYP 50 2.2V