US 5,706,447 A · System for automatic reconfiguration termination to multi-processor bus without added expense of removable termination module

Abstract

A modular computer bus providing a system for automatically maintaining proper bus termination. A module connector is located at on end of the bus. A switch device is located at the end of the bus as close as possible to the connector. The switch device couples a termination device to the end of the bus when the switch device is in an on state. The switch device is in the on state when no module is present in the connector and in an off state when a module, such as a processor module, is present in the connector. When the switch device is in the off state, the termination device is not coupled to the bus. Instead the end of the bus is terminated by a termination device on the module. Thus, computer bus is correctly terminated automatically when a module is inserted into or removed from the connector. Thus a bus structure is provided for implementing a bus standard while providing modularity and automatically maintaining proper bus termination. The superior flexibility, upgradeability and serviceability benefits of a modular bus system are achieved without incurring the increased damage risk, cost, and user confusion disadvantages of prior termination techniques.

Claims28

Dependent claims

A system which automatically and selectively terminates a computer bus as add-in modules are added to and removed from the bus, the system comprising:

a computer bus having a first end and a second end, wherein said computer bus requires termination located at said first end;
a first termination device, located near said first end of said computer bus, for terminating said first end of said computer bus;
a connector located near said first end of said computer bus and coupled to said first end of said computer bus, wherein said connector is adapted to receive interchangeable modules;
a first interchangeable module adapted for insertion into said connector, wherein said first interchangeable module comprises a second termination device for terminating said first end of said computer bus;
and
a switch coupled to said first end of said computer bus and to said first termination device, wherein said switch is responsive to the presence of said first interchangeable module in said connector to electrically couple said first termination device to said first end of said computer bus only when said first interchangeable module is not present in said connector, wherein said first termination device terminates said first end of said computer bus when said first interchangeable module is not present in said connector;
and
wherein said second termination device terminates said first end of said computer bus when said first interchangeable module is present in said connector.

5 more elements

A computer system, comprising

a motherboard;
a computer bus having a first end and a second end, wherein said computer bus is located primarily on said motherboard, and wherein said computer bus requires termination located at said first end and termination located at said second end for proper operation;
at least one bus device coupled to said computer bus;
a first termination device for terminating said first end of said computer bus, wherein said first termination device is located on said motherboard near said first end of said computer bus;
a second termination device which terminates said second end of said computer bus, wherein said second termination device is located near said second end of said computer bus and is electrically coupled to said second end of said computer bus;
a first connector adapted to receive interchangeable modules, wherein said first connector is located on said motherboard near said first end of said computer bus and coupled to said first end of said computer bus;
a first interchangeable module adapted for insertion into said first connector, wherein said first interchangeable module comprises a third termination device for terminating said first end of said computer bus;
wherein said first end of said computer bus is effectively located on said first interchangeable module when said first interchangeable module is present in said first connector, and wherein said first end of said computer bus is effectively located on said motherboard when said first interchangeable module is not present in said first connector;
and
a switch, located on said motherboard, coupled to said first termination device and to said first end of said computer bus, wherein said switch is responsive to the presence of said first interchangeable module in said first connector to electrically couple said first termination device to said first end of said computer bus only when said first interchangeable module is not present in said first connector, wherein said first termination device terminates said first end of said computer bus when said first interchangeable module is not present in said first connector;
and
wherein said third termination device terminates said first end of said computer bus when said first interchangeable module is present in said first connector.

9 more elements

Dependencies are inferred from the claim text.

System for automatic reconfiguration termination to multi-processor bus without added expense of removable termination module

Life of this patent

System for automatic reconfiguration termination to multi-processor bus without added expense of removable termination module

Life of this patent

Abstract

Claims28