Unisys Corporation

Micron Electronics, Inc.

Micron Technology Incorporated

Paul A Laberge

James W Meyer

Larry L Byers

Gregory B Wiedenman

Gary R Robeck

Terry J Brunmeier

David J Tanglin

Randy L DeGarmo

Donald E Harding

A system for communicating information between requester and target devices in a computer having a multiple bus architecture. The system supports deferred transactions of cache line read requests over a host bus, e.g., the Pentium II or Pentium Pro (P ) bus. The system employs a host bridge to issue deferred transactions over the P bus without interrupting or involving the main processor. The system comprises a first device, electrically connected to the requester, which receives a request from the requester. The system further comprises a second device, electrically connected to the first device, which transmits the request with a defer enable signal over the P bus. The system further comprises a third device, electrically connected to the P bus, which communicates the request having a defer enable signal to the target.

System for peer-to-peer mastering over a computer bus

A method of communication between requester and target devices in a computer system having a multiple bus architecture. The method supports deferred transactions of cache line read requests over a host bus, e.g., the Pentium II or Pentium Pro (P6) bus. The method employs a host bridge to issue deferred transactions over the P6 bus without interrupting or involving the main processor. The method comprises the act of establishing a handshake with a host master and issuing a request over the host bus. The method further comprises the act of acknowledging the request and transmitting a deferred response to the requester.

Method of peer-to-peer mastering over a computer bus

A system for communicating information between requester and target devices in a computer having a multiple bus architecture. The system supports deferred transactions of cache line read requests over a host bus, e.g., the Pentium II or Pentium Pro (P6) bus. The system employs a host bridge to issue deferred transactions over the P6 bus without interrupting or involving the main processor. The system comprises a first device, electrically connected to the requester, which receives a request from the requester. The system further comprises a second device, electrically connected to the first device, which transmits the request with a defer enable signal over the P6 bus. The system further comprises a third device, electrically connected to the P6 bus, which communicates the request having a defer enable signal to the target.

A method and apparatus for increasing the efficiency of a dynamic read and/or write operation of a memory element within a computer system. The dynamic read and/or write operation may be performed when the computer system is in a functional mode or a test mode. The present invention may reduce the number of bits that are required to be serially shifted into a design by providing an auto-increment block. It is recognized that most multi-word access to a memory are made to sequential address locations within the memory. The auto-increment block takes advantage of this and automatically manipulates the address thereby not requiring subsequent addresses to be serially shifted into the design. Further, the control word may be stored within the design for subsequent accesses. That is, the support controller may shift a starting address and a control word into the design. The addresses for subsequent accesses may be generated by the auto-increment block, thereby only requiring that the support controller shift a data word to/from the design. This may significantly reduce the time necessary perform the subsequent read and/or write operations.

Method and apparatus for dynamically testing a memory within a computer

A circuit employing two delayed bus clock signals and timer logic to minimize the dead bus time occurring between consecutive bus drivers and providing additional protection against multiple, simultaneous bus drivers for a communications bus in a computer system. Skewed enable and disable clock signals based on an original bus clock feed combinational logic to set a transceiver enable line when control of the bus is granted for bus transfers. Bus transfers remain enabled, through use of a feedback path, as long as a bus grant signal is active. When the last cycle of the bus transfer occurs, or a bus transfer error occurs, the transceiver enable line goes inactive, thereby allowing other components coupled to the bus to gain control. Test mode and bus transfer status lines provide further mechanisms for controlling bus transfer operation.

Bus grant overlap circuit

A power loss detection and recovery circuit for providing continued memory operations upon loss of a supply voltage. Multiple independent power domains, each of which provides an electrically isolated supply voltage, are used to provide power to redundant memory circuitry. A loss of voltage or a degenerative voltage within a power domain is detected, and circuitry residing on a different operational power domain provides recovery operations to allow continued memory activity within that operational power domain. The memories residing in an adjacent pair of power domains redundant, and are therefore written to and read from simultaneously, and circuitry within an operational power domain will prevent further reading of data from the memory residing in a failed power domain, and will also prevent further writing of data to the memory residing in the failed power domain upon recognition of a failed supply voltage within a power domain.

Growing community of inventors

Coon Rapids, MN, United States of America

Paul A Laberge