Converting a central arbiter to a slave arbiter for interconnected systems
First Claim
1. A method of transferring data between a host computer system having a host system bus and at least one interconnected computer subsystem having a subsystem bus, comprising:
- maintaining control of said subsystem bus by a conversion logic device connected intermediate said host bus and said subsystem bus to prevent a busmaster device, connected to said subsystem bus, from transferring data on said host bus;
requesting access to said host system bus, by a requesting busmaster device connected to said subsystem bus;
in response to said request for access, arbitrating by said conversion logic device, for control of said host system bus to prevent said host computer system from prematurely transferring data onto said host bus;
subsequent to obtaining control of said host system bus, releasing control of said subsystem bus by said conversion logic device such that said requesting busmaster device can gain control of said subsystem bus; and
transferring data between said busmaster device on said subsystem bus and said host system bus when said busmaster device controls said subsystem bus and said conversion logic device controls said host bus.
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Accused Products
Abstract
A method and apparatus are disclosed for allowing at least one computer subsystem, having a central arbiter, to be interconnected with a host system also including a central arbiter. Conversion logic is added to each computer subsystem desired to be interconnected to the host. The conversion logic is positioned between the arbitration buses of the host system and the subsystem and includes two requesting arbiters, one of which arbitrates for the host system arbitration bus, and the other which arbitrates for the subsystem arbitration bus. At the default state, the conversion logic has successfully arbitrated for, and is maintaining control of the subsystem bus. After a request from a subsystem device for access to the host bus, the conversion logic arbitrates for control of the host bus. When control of the host bus is awarded to the conversion logic, control of the subsystem bus is released and the requesting subsystem device can transfer data between the subsystem and host.
36 Citations
9 Claims
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1. A method of transferring data between a host computer system having a host system bus and at least one interconnected computer subsystem having a subsystem bus, comprising:
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maintaining control of said subsystem bus by a conversion logic device connected intermediate said host bus and said subsystem bus to prevent a busmaster device, connected to said subsystem bus, from transferring data on said host bus; requesting access to said host system bus, by a requesting busmaster device connected to said subsystem bus; in response to said request for access, arbitrating by said conversion logic device, for control of said host system bus to prevent said host computer system from prematurely transferring data onto said host bus; subsequent to obtaining control of said host system bus, releasing control of said subsystem bus by said conversion logic device such that said requesting busmaster device can gain control of said subsystem bus; and transferring data between said busmaster device on said subsystem bus and said host system bus when said busmaster device controls said subsystem bus and said conversion logic device controls said host bus. - View Dependent Claims (2, 3)
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4. A system for transferring data between a host computer system having a host system bus with at least one host busmaster device connected thereto, and at least one interconnected computer subsystem having at least one subsystem bus with at least one busmaster device connected thereto, comprising:
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means, in said at least one busmaster device, for requesting access to said host system bus; conversion logic means, connected intermediate said host bus and said subsystem bus, comprising; means for maintaining control of said subsystem bus to prevent said at least one busmaster device from prematurely transferring data onto said host bus; means for arbitrating for control of said host system bus, in response to said request for access, to prevent said host computer system from transferring data onto said host bus; and means for releasing control of said subsystem bus, subsequent to obtaining control of said host system bus, such that said requesting busmaster device can gain control of said subsystem bus; and means for transferring data between said busmaster device on said subsystem bus and said host system bus when said subsystem busmaster device controls said subsystem bus and said conversion logic controls said host bus. - View Dependent Claims (5, 6, 7, 8, 9)
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Specification