12.
    发明专利
    未知

    公开(公告)号:DE69423056T2

    公开(公告)日:2000-09-14

    申请号:DE69423056

    申请日:1994-05-25

    Applicant: IBM

    Abstract: An arbitration mechanism 42 is provided for use in a computer system 10 which comprises (i) a central processing unit (CPU) 24; (ii) a first system bus 36 which connects the CPU 24 to system memory 32 so that the CPU 24 can read data from, and write data to, the system memory 32; (iii) a second system bus 16 connected to the CPU 24; (iv) a host bridge 20 connecting the second-system bus 16 to a peripheral bus 22, the peripheral bus 22 having at least one peripheral device 18 attached thereto; and (v) an input/output (I/O) bridge 78 connecting the peripheral bus 22 to a standard I/O bus 92, the standard I/O bus 92 having a plurality of standard I/O devices 90 attached thereto. The arbitration mechanism 42 comprises (i) a first level 100 of logic for arbitrating between the plurality of standard I/O devices 90, wherein one standard I/O device 90 is selected from a plurality of the standard I/O devices 90 competing for access to the standard I/O bus 97, and (ii) a second level 102, 104 of logic for arbitrating between the selected standard I/O device 90, the CPU 24 and the at least one peripheral device 18, wherein one of the selected standard I/O device 90, the CPU 24 and the at least one peripheral device 18 is selected to access the peripheral bus 22. The arbitration mechanism 42 includes sideband signals which connect the first 100 and second levels 102, 104 of arbitration logic and include arbitration identification information corresponding to the selected standard I/O device 90.

    13.
    发明专利
    未知

    公开(公告)号:DE69423056D1

    公开(公告)日:2000-03-30

    申请号:DE69423056

    申请日:1994-05-25

    Applicant: IBM

    Abstract: An arbitration mechanism 42 is provided for use in a computer system 10 which comprises (i) a central processing unit (CPU) 24; (ii) a first system bus 36 which connects the CPU 24 to system memory 32 so that the CPU 24 can read data from, and write data to, the system memory 32; (iii) a second system bus 16 connected to the CPU 24; (iv) a host bridge 20 connecting the second-system bus 16 to a peripheral bus 22, the peripheral bus 22 having at least one peripheral device 18 attached thereto; and (v) an input/output (I/O) bridge 78 connecting the peripheral bus 22 to a standard I/O bus 92, the standard I/O bus 92 having a plurality of standard I/O devices 90 attached thereto. The arbitration mechanism 42 comprises (i) a first level 100 of logic for arbitrating between the plurality of standard I/O devices 90, wherein one standard I/O device 90 is selected from a plurality of the standard I/O devices 90 competing for access to the standard I/O bus 97, and (ii) a second level 102, 104 of logic for arbitrating between the selected standard I/O device 90, the CPU 24 and the at least one peripheral device 18, wherein one of the selected standard I/O device 90, the CPU 24 and the at least one peripheral device 18 is selected to access the peripheral bus 22. The arbitration mechanism 42 includes sideband signals which connect the first 100 and second levels 102, 104 of arbitration logic and include arbitration identification information corresponding to the selected standard I/O device 90.

    ARBITRATION CONTROL FOR DUAL BUS ARCHITECTURE COMPUTER

    公开(公告)号:NZ245345A

    公开(公告)日:1995-07-26

    申请号:NZ24534592

    申请日:1992-12-02

    Applicant: IBM

    Abstract: A computer system is provided comprising system memory and a memory controller for controlling access to system memory, a central processing unit electrically connected with the memory controller, and a bus interface unit electrically connected to the memory controller by a system bus and electrically connected to a plurality of input/output devices by an input/output bus. The bus interface unit is able to sense when said one of said input/output devices has completed a read or write operation over said input/output bus, and includes a buffer circuit wherein read and write data transferred between the system bus and the input/output bus via the bus interface unit is temporarily stored during the transfer. Arbitration control logic resides in said bus interface unit and interacts with a central arbitration controller which resides on the system bus. The central arbitration controller responds to the arbitration control logic to simultaneously perform (i) arbitration cycles wherein the central arbitration controller arbitrates between the plurality of input/output devices and the central processing unit to determine which of the input/output devices or the central processing unit should be granted control of the input/output bus and (ii) grant cycles wherein the central arbitration controller grants control of the input/output bus and extends control of the system bus to one of the input/output devices or the central processing unit.

    Arbitration control logic for computer system having dual bus architecture

    公开(公告)号:AU651747B2

    公开(公告)日:1994-07-28

    申请号:AU2979492

    申请日:1992-12-02

    Applicant: IBM

    Abstract: A computer system is provided comprising system memory and a memory controller for controlling access to system memory, a central processing unit electrically connected with the memory controller, and a bus interface unit electrically connected to the memory controller by a system bus and electrically connected to a plurality of input/output devices by an input/output bus. The bus interface unit is able to sense when said one of said input/output devices has completed a read or write operation over said input/output bus, and includes a buffer circuit wherein read and write data transferred between the system bus and the input/output bus via the bus interface unit is temporarily stored during the transfer. Arbitration control logic resides in said bus interface unit and interacts with a central arbitration controller which resides on the system bus. The central arbitration controller responds to the arbitration control logic to simultaneously perform (i) arbitration cycles wherein the central arbitration controller arbitrates between the plurality of input/output devices and the central processing unit to determine which of the input/output devices or the central processing unit should be granted control of the input/output bus and (ii) grant cycles wherein the central arbitration controller grants control of the input/output bus and extends control of the system bus to one of the input/output devices or the central processing unit.

    17.
    发明专利
    未知

    公开(公告)号:DE69421453T2

    公开(公告)日:2000-05-18

    申请号:DE69421453

    申请日:1994-05-25

    Applicant: IBM

    Abstract: A direct memory access (DMA) support mechanism is provided for use in a computer system 10 which comprises (i) a central processing unit (CPU) 24 connected to system memory 32 by a first system bus 36, and a second system bus 16 connected to the CPU; (ii) a host bridge 20 connecting the second system bus to a peripheral bus 22; (iii) an input/output (I/O) bridge 78 connecting the peripheral bus to a standard I/O bus 92, the standard I/O bus having a plurality of standard I/O devices 90 attached thereto; and (v) arbitration logic 42 which functions in an arbitration mode for arbitrating between the plurality of standard I/O devices competing for access to the standard I/O bus, and in a grant mode wherein a selected standard I/O device is granted access to the standard I/O bus. The DMA support mechanism comprises a direct memory access (DMA) controller 40 for performing DMA cycles on behalf of the selected standard I/O device, and direct memory access (DMA) support logic for enabling the DMA cycles to be performed over the peripheral bus. The DMA support logic includes sideband signals directly connecting the DMA controller with the I/O bridge, the sideband signals including information identifying the bus size of the selected I/O device for which the DMA controller is performing the DMA cycles.

    18.
    发明专利
    未知

    公开(公告)号:AT186412T

    公开(公告)日:1999-11-15

    申请号:AT94303783

    申请日:1994-05-25

    Applicant: IBM

    Abstract: A direct memory access (DMA) support mechanism is provided for use in a computer system 10 which comprises (i) a central processing unit (CPU) 24 connected to system memory 32 by a first system bus 36, and a second system bus 16 connected to the CPU; (ii) a host bridge 20 connecting the second system bus to a peripheral bus 22; (iii) an input/output (I/O) bridge 78 connecting the peripheral bus to a standard I/O bus 92, the standard I/O bus having a plurality of standard I/O devices 90 attached thereto; and (v) arbitration logic 42 which functions in an arbitration mode for arbitrating between the plurality of standard I/O devices competing for access to the standard I/O bus, and in a grant mode wherein a selected standard I/O device is granted access to the standard I/O bus. The DMA support mechanism comprises a direct memory access (DMA) controller 40 for performing DMA cycles on behalf of the selected standard I/O device, and direct memory access (DMA) support logic for enabling the DMA cycles to be performed over the peripheral bus. The DMA support logic includes sideband signals directly connecting the DMA controller with the I/O bridge, the sideband signals including information identifying the bus size of the selected I/O device for which the DMA controller is performing the DMA cycles.

    BIDIRECTIONAL DATA STORAGE FACILITY FOR BUS INTERFACE UNIT

    公开(公告)号:CA2080210C

    公开(公告)日:1998-10-27

    申请号:CA2080210

    申请日:1992-10-08

    Applicant: IBM

    Abstract: The present invention provides a bus to bus interface unit for computer systems having dual bus architecture, such as a system bus and an I/O bus. The bus interface unit includes an asynchronous bidirectional temporary data storage function for data being transferred between the two buses to and from devices coupled to each of the two buses. Preferably the storage function operates in modes that will accommodate individual transfers of data, data streaming, and data burst transfers, and can accommodate transfers of information from contiguous addresses without initiating a new request for each address.

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