RMII INTERFACE SATISFYING ETHERNET STANDARD

摘要

PURPOSE: An RMII interface satisfying an Ethernet standard is provided, in which in/output pins are reduced than a MII(Media independent Interface). CONSTITUTION: A reception control block(110) outputs a packing control signal of received data(rxd(1:0)) according to an input of signals(CRS_DV,bps10_100). A low speed mode receive counter(120) generates a signal(rx_flag_wire) for sampling input data every 10th reference clock(REF_CLK) according to a counter enable signal based on a 10Mbps rate of the control block(110). A compression output control and demultiplexing block(130) packs received data at a rising edge every reference clock according to a packing enable signal(packing_en) from the block(110), and packs the received data every 10th reference clock according to a signal of the low speed mode receive counter(120). A receive output buffer(140) buffers packed data from the block(130). A low speed mode transmission counter(210) receives the signals(CRS_DV,bps10_100) and the reference clock(REF_CLK) and counts for 100Mbps transmission by a signal(tx_start) indicating an input of transmission data. A transmission preamble counter(220) counts to send preamble data according to a counter enable signal. A transmission FSM control block(230) generates the transmission enable signal and preamble and SFD data in response to the signals(CRS_DV,bps10_100,tx_start) and outputs transmission data. A multiplexer(240) multiplexes the transmission data by two bits according to a control of the control block(230). A transmission output buffer(250) outputs demultiplexed transmission data.