Method for synchronizing clocks in a distributed communication system

a communication system and distributed communication technology, applied in multiplex communication, data switching networks, star/tree networks, etc., can solve the problems of high cost and inefficiency of the use of oscillators for generating signals used for monitoring clock signals in the guardian of a bus node in the communication system, and achieve high precision

Inactive Publication Date: 2005-06-30
MOTOROLA INC +5
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0015] According to the present invention it is suggested to effect a clock signal monitoring using an internal clock signal having a lower accuracy than the clock signal to be monitored. Of course, according to the present invention only a coarse monitoring of the synchronized clock signal can be achieved. But the achievable accuracy is accurate enough in order to determine larger deviations of the monitored clock signal from a nominal signal and is for example +/−50%. Large deviations may be caused by a crystal that is oscillating at a different harmonic or a frequency divider inside the communication controller that is operating at

Problems solved by technology

However, the use of oscillators for generating the signals used for monitoring the clock

Method used

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  • Method for synchronizing clocks in a distributed communication system
  • Method for synchronizing clocks in a distributed communication system
  • Method for synchronizing clocks in a distributed communication system

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examples

[1313] This section describes in more detail the Host-communication controller interaction for the wakeup in two typical situations. Firstly, it is described, how one Host wakes both channels of a two-channel system. Secondly, it is described, how one node connected to only one channel of a two-channel system wakes this channel and how a sync node (connected to both channels) wakes the other channel.

[1314] Since also the transition between wakeup and startup is described, the examples may be more readily understood with a prior understanding of FlexRay startup, which is described in subsequent sections.

Two Channel Wakeup by One Node

[1315]FIG. 58 shows a Simple Wakeup. Larger (ms range) amount of times are represented by dotted lines.

[1316] This section describes a FlexRay system with two channels configured and operating in time-triggered distributed protocol mode. It is described how one sync-node first wakes the cluster and then performs the startup. [1317] Node 1 is awake. I...

implementation example

Mailbox Buffer Control Register Fields

[2430] The CHI shall provide one Buffer Control Register to configure the message mailbox buffers (as Transmit, Dedicated Receive or FIFO Receive buffer) and to control host's access to the message buffers.

[2431] This control register shall provide one byte for each mailbox buffer.

TABLE 57Mailbox Buffer Control Register FieldsControlFIFOFlagBitsTx BufferRx BufferBufferCommentCFG1’1’ = Transmit Buffer’0’ = Receive Buffer’0’Message BufferConfiguration BitCFG_SR1’1’ = Mailbox Buffer’1’ = Buffer and the—’0’ = Mailboxand the associated filterassociated filter canBuffer and thecan be configured onlybe configured onlyassociated filterduring CC_SoftReset.during CC_SoftReset.can be configuredduring normaloperation.Transmission1’1’ = Single-shot Mode——only for staticMode(transmit Null Frame ifslotsbuffer not updated,Commit flag = ’0’)’0’ = Continuous Mode(See above)Commit1’0’ = buffer not’1’ = buffer updated—Commit FlagFlagupdated, ’1’ = buffer(valid...

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Abstract

The invention refers to one of a number of nodes of a communication system. The nodes are connected to a communication media for transmitting data among the nodes. Said one node comprises a communication controller, across which the node is connected to the communication media, and a bus guardian for controlling access of the communication controller to the communication media. In order to provide a cheap but nevertheless reliable way for monitoring the synchronized clock signal of a node of a communication system and in particular for detecting deviations of the synchronized clock signal it is suggested that a synchronized clock signal from the communication controller is made available to the bus guardian, and that the bus guardian comprises means for monitoring the synchronized clock signal using a bus guardian internal clock signal, which is generated by means of an electronic circuit and which is less accurate than the synchronized clock signal to be monitored.

Description

[0001] This application is a continuation of PCT / EP03 / 03992 filed on Apr. 16, 2003 and also claims Paris Convention priority of EP 02 008 171.7 and DE 102 16 984.5 both filed on Apr. 16, 2002, the entire disclosures of which are all hereby incorporated by reference.BACKGROUND OF THE INVENTION [0002] The present invention refers to one of a number of nodes of a communication system. The nodes are connected to a communication media for transmitting data among the nodes. Said one node comprises a communication controller, across which the node is connected to the communication media, and a bus guardian for controlling access of the communication controller to the communication media. [0003] Furthermore, the invention refers to a method for monitoring a synchronized clock signal from a communication controller of a node making part of a number of nodes of a communication system. The nodes are connected to a communication media for transmitting data among the nodes. Said node comprises a...

Claims

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Application Information

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IPC IPC(8): H03M13/09H03M13/43H04J3/06H04L12/26H04L12/413H04L12/417H04L12/44H04L12/64
CPCH03M13/09H04J3/0652H04J3/0694H04L2012/6459H04L12/44H04L2012/6435H04L2012/644H04L12/417H04L12/40026H03M13/43H04J3/0682H04L7/0331H04L12/4035H04L12/6418H04L43/00H04L43/0847H04L2012/40241H04L2012/40273
Inventor FOREST, THOMASHEDENETZ, BERNDRAUSCH, MATHIASTEMPLE, CHRISTOPHEREISELE, HARALDELEND, BERNDUNGERMANN, JORNKUHLEWEIN, MATTHIASBELSCHNER, RALFLOHRMANN, PETERBOGENBERGER, FLORIANWUERZ, THOMASMILLSAP, ARNOLDHEUTS, PATRICKHUGEL, ROBERTFUHRER, THOMASMULLER, BERNDHARTWICH, FLORIANZINKE, MANFREDBERWANGER, JOSEFEBNER, CHRISTIANWEILER, HARALDFUHRMANN, PETERSCHEDL, ANTONPELLER, MARTIN
Owner MOTOROLA INC
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