Synchronous medium access controller

Abstract

This invention discloses a kind of synchronous medium access controller SMAC. The aim is to provide a kind of SMAC with time transmission, time detection and clock regeneration functions in order to achieve high precise time transmission and regenerate synchronous second pulse clock signal required in the multinode synchronous test on MAC layer. It is a integrate circuit, which is composed of medium access controller, time transmission unit, time identification processing unit, time synchronous processing unit, clock signal regeneration unit and local clock processing unit. Each unit is connected by bus interface or clock signal lines. This invention has high precision.

Description

technical field [0001] The present invention relates to a medium access controller (MAC, Medium Access Controller), especially a synchronous medium access controller (SMAC, Synchronization Medium Access Controller) that can realize high-precision time transfer and clock regeneration functions for industrial testing and automation system networks, especially Suitable for high precision time transfer and clock regeneration in miniature network terminals and test probes. Background technique [0002] MAC-based network technology has been rapidly developed and widely used. In order to realize business applications such as synchronous testing of different nodes, nodes need to be unified in time, especially with respect to a certain time standard. Currently available MACs on the market and MACs published in technical documents do not have the functions of time transfer and clock regeneration, which makes the methods of using MAC for time transfer, such as SynUTC and IEEE 1588, mor...

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Problems solved by technology

Currently available MACs on the market and MACs published in technical documents do not have the functions of time transfer and clock regeneration, which makes the methods of using MAC for time transfer, such as SynUTC and IEEE 1588, more complicated and require the support and participation of high-level protocols. The network adds a large load, and because the MAC does not have the time transfer function, the network time transfer method is closed-loop, that is, an independent round-trip transfer packet process is required to estimate the one-way transfer delay of the time synchronization frame, so that the time transfer accuracy At the same time, because the MAC does not have the clock regeneration function, that is, it cannot regenerate the synchronized second pulse clock signal at each node, so the standard time pulse signal is lacking in the multi-network synchronization test as a reference. It is more difficult to generate synchronous sampling pulses

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