Connect Tech CTIM-00044 user manual Bus Contention on Differential Multi-drop Networks

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Connect Tech Blue Heat/Net Sync User Manual

Bus Contention on Differential Multi-drop Networks:

Bus contention occurs when two or more devices enabled on a bus attempt to run the bus to opposite logic values. From the diagram above, we can see that there are multiple differential transmitters (TXD) on the bus. To avoid the bus contention problem, the differential transmitter features a tri-state, or high impedance mode controlled by an input pin (enable). Software and hardware in the Blue Heat/Net Sync and the differential devices will always place its transmitter into the high impedance mode when not transmitting. This feature is managed by the Blue Heat/Net Sync and is fully transparent to your application.

For example, in a multi-drop network, the differential transmitter is enabled prior to the master initiating transmission. When transmission is complete, the transmitter is placed in high impedance mode. Each slave will receive that transmission from the master. (A protocol must be in place to address, or select, the desired slave device, but that discussion is beyond the intentions of this tutorial, and is entirely application dependent). When the slave device has received the data, it will respond by enabling its transmitter and transmitting data onto the bus, then placing its transmitter into high impedance mode, just as the master did.

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Contents Blue Heat/Net Sync Limited Lifetime Warranty Telephone/Facsimile Email/InternetMail/Courier Class a Computing Device Preliminary Testing is still pendingTable of Contents Installing the Blue Heat/Net Sync Configuration Manager List of Figures List of Tables Introduction Understanding Virtual COM Ports Blue Heat/Net Sync Installation OverviewEthernet LEDs Connecting the Blue Heat/Net Sync to Your NetworkConnecting Serial Devices Serial Port LEDsConnections RS-422/V.11 Connections Blue Heat/Net Synchronous ClockingRecommended Pinouts for V.28 RS-232 Loopback Connector Loopback ConnectorsConnecting Power DC Power ConnectorPhoenix Locking Screw Terminal Connector 5VDC Selecting a Special Operation Activating the Special Operations Mode and Default SettingsLED Error Codes Power On DiagnosticsCRC Connect Tech Setting a Static or Dynamic IP Address SCM Serial Configuration ManagerSCM Cabling requirements Set the IP Address Using the Serial Configuration Manager Set the IP Address Using the Web Configuration Manager Operating System Software Configuration ManagerBootloader Serial Configuration Manager SCM ApplicationDescription CDS Configuration Data SpaceAccess to CDS Parameters Configuration Data Space CDSBrief Command List SCM Serial Configuration ManagerGetting Access to the SCM SCM Command ReferenceBoot Syntax boot mode= file= delay= Command DetailsYes Myip= mip= Save File= Signing In to the Web Configuration Manager WCM Web Configuration ManagerBlue Heat/Net Sync Settings Configure Blue Heat/Net Sync Settings Configure Advanced Serial SettingsPage Restore Defaults Configure FirmwareSaving To Flash Restore Default SettingsMonitor Serial Port Traffic Monitoring Your Blue Heat/NetMonitor Network Traffic Monitor TCP/IP StatisticsMy Blue Heat/Net Sync My Blue Heat/Net Sync Hardware Details Blue Heat/Net Sync Driver/Software Installation CD Installing the Blue Heat/Net Sync Configuration ManagerBlue Heat/Net Sync Software Installation Screen Page Page Device Installation Running the Configuration ManagerAdd New Blue Heat/Net Sync Configure Default Blue Heat/Net SyncAuto Discover Blue Heat/Net Sync Screen Auto Discover Blue Heat/Net SyncUpgrade using SCM Serial Configuration Manager Upgrade using WCM Web Configuration ManagerChip Selects Hardware InformationHardware Resources Chip SelectsAddress Range hex Base Address MapInterrupts Gpio Bits Direction UsageA11 A10 Iusc AccessMemory Map of Iusc and PLD Functions ColdFire 5272 BusFunction PLD Resource AccessAddress Area item Register Offset Accessed Hex PLD Memory Map TableBit Serial Data transfers only IUSC-1 PLD Registers Offset Reg Name Valid Bit Descriptions Reset Values HexFSM CTSM1 CTSM0 PLD ID System Block Diagrams Revision BHNPortSettings Port Settings, Clock Setup and General SettingsSerial Mode smode Async MonoSync BiSync Trans-BiSync Iusc Clocking Logic Blue Heat/Net Sync Specifications Telnet Protocol DescriptionsDB-25 Female Pinouts Mode Equivalent Standard Electrical Typical VoltagePinouts DB-25 Female PinoutsDB-9 Female Pinouts DB-9 Female PinoutsRack Mount Option SCM Operation Settings Default SettingsNetwork Settings Boot SettingsUsing WCM Common Configuration SetupsStatic IP Setup Using SCMDhcp Setup How the Blue Heat/Net Sync Boots UpBootup Sequence Bootup SequenceAsynchronous Communications Tutorial Flowchart of Special Operations Mode using the reset buttonRS485/RS422/V.11 Details Serial Line Interface TutorialRS-232 Line Interface Differential Line InterfacesBasic 4-Wire, Full Duplex Communications Basic Wire, Half Duplex Multi-drop Connection Multi-drop 4-Wire, Full Duplex CommunicationsBus Contention on Differential Multi-drop Networks Termination Resistors in Differential Networks Termination Resistors in Differential Networks