COMMUNICATION MODULE FOR OUTPUTTING COPY OF REGISTER OF RE-TIMER TO HOST DEVICE, PARTICULARLY FOR ENABLING A MEMORY UNIT OF A MICROCOMPUTER TO STORE A COPY OF A REGISTER WHOSE VALUE IS UPDATED BY A RE-TIMER WITH CERTAIN TIMING

摘要

PURPOSE: A communication module for outputting a copy of a register of a re-timer to a host device is provided to enable a microcomputer to coordinately manage content of a register and transmit a value of the register at a high speed in response to a request of a host device. CONSTITUTION: An MAC layer(1) coordinately manages communication modules. An MDIO(Medium Dependent Input/Output) host(2) controls a communication module(12) through a serial bus(MDIO)(8). A microcomputer(3) performs overall controlling on the communication module(12) connected to the MAC layer(1). An XAUI(10(X)G Attachment Unit Interface) re-timer(9) controls a physical layer of communication in the communication module(12). The XAUI re-timer(9) includes function blocks of PMA(Physical Media Attachment)(15), PCS(Physical Coding Sublayer)(16) and XGXS(10(X)G eXtension Sublayer)(17) each having a register(10) defined by IEEE802.3ae. An SRAM(Static Random Access Memory)(5) includes an IEEE/XENPAK(10(X)G EtherNet(R) transceiver PAcKage) virtual register(6) for maintaining content of the IEEE register(10) and content of a register defined by the XENPAK. A flash ROM(7) stores a program executed by the microcomputer(3) and initial values of the IEEE register and the XENPAK register.