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1、Hardware Design of High Speed Switch Fabric IC Overall Architecture8x8 TDM switchSERTXIOSERTXIOSERTXIOSERTXIOSERTXIOSERTXIOSERTXIOSERTXIORXPLLTXPLLOverall Architecture of the8x8 SwitchRXIODESERRXIODESERRXIODESERRXIODESERRXIODESERRXIODESERRXIODESERRXIODESERBypassFeatures Supports protocol-independent
2、 switching.Data are encapsulated in switching packets across the fabric.Switching packet size is 64 bytes Supports 8x8 switch with each port up to 2.563.2Gbps Supports scalable multichip switchingFeatures 2.563.2Gbps I/O:-CML IO driver -Embedded SERDES -Integrated CDRDeSerializerDeSerializer Convert
3、s the CML differential input to single bit input data through input CML buffer Converts the single bit input data at 2.563.2Gbps rate into 16/20 bit data bus at 160MHz clock rate Input reference clock 160MHz RX CML(clock multiplying unit)produces 1.28-1.6GHz clock for data recovery from external 160
4、MHz clockDeSerializer Input reference clock 160MHz CDR(Clock Data Recovery)block produces 1.28-1.6GHz clock for data recovery from external 160MHz clock and input data Front End receiver use recovered clock to sample and de-multiplexing single input data to 4 bit data bus at 640MHz clock Use 4 to 16
5、/20 DEMUX to produce 16/20 bit data bus at 160MHzDeSerializer Comma detector to detect comma word to align data byte boundary Use 8/10bit decoder to decode start of packet(SOP),destination port and data8x8 TDM switch 8x8 TDM switch Performs the first stage load balanced traffic redistribution after
6、the input FIFO queue Input to first stage switch is consecutive 64 byte packet at each input port Outputs of first stage switch include data,data valid,destination port,and sequence ID8x8 TDM switch Performs the second stage Birkhoff-von-Neumann switch after the resequence and output buffer queue In
7、put to second stage switch is distributive data from resequence and output buffer queue Outputs of second stage switch include data,start of packet,and destination port8x8 TDM switch Operates at 160MHz clock with clock period 6.2ns For 2.56Gbps(64 bytes/packet)=5Mpackets/s 200ns/packet operation tim
8、e(time slot)=32 cycles for 160MHzSerializer Performs 16/20b encoding function Parallel to serial conversion convert 20/16 bit data bus at 160MHz to single bit output at 2.563.2Gbps Differential CML outputPLL TXPLL to generate 160MHz clock for digital core TXPLL to generate reference 160MHz clock for
9、 synthesizing 1.281.6GHz clock for serializer RXPLL to generate 1.281.6GHz clock for CDR from external 160MHz clockTasks PLLTR-PLL(TX and RX)design and Hspice simulation DESER-DeSerializer(CDR)design and Hspice simulation SWH-8x8 TDM switch design,synthesis,place and route,and verification CCODEC-Comma detect and 8/10b decoder,8/10b encoderTasks SERCMLSerializer and CML high speed IO buffer design and Hspice simulation APRDAnalog customized layout for DERSER APRS-Analog customized layout for SER and driver Full chip integration and verification Architecture specs
