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EP0130470A2
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System and method for resolving contention among a plurality of asynchronous bus master devices connected to a common bus
Assignee: International Business Machines Corp
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Filing: 1984-06-20
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Granted: —
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Expires: 2004-06-20
Abstract
Abstract Independent asynchronous bus master devices share a common bus with control lines serially connecting each bus master in a daisy-chain configuration. A Bus Acknowledge signal (34) is received by a local bus master which is thereby enabled (31, 33) to seize control of the bus without an input synchronization delay by first inhibiting (signal 40) synchronization means (41, 41 A, 42, 43) to prevent the passage of the Bus Acknowledge signal (34) to a downstream device for a period of time sufficient to stabilize a Bus Acknowledge Pass signal (44) indicating such passage. In that manner, the Bus Acknowledge signal (44) may be used to control the immediate enabling of local bus seizure thereby avoiding local synchronization delay.
Inventors
- 👤 Kent Steven Norgren
- 👤 Robert Eric Vogelsberg
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-26 21:09
CPC Classifications
G; G06; G06F; G06F13/00; G06F13/14; G06F13/36; G06F13/368; G06F13/37
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
141 words
A system for resolving contention among a plurality of asynchronous bus master devices (10, 11, 12) connected to a common bus (13), including a bus arbitrator device (16), means (17, 19, 21) for serially connecting each said bus master device in order of priority with the highest priority bus master device (10) directly connected to said bus arbitrator device (16) and local line control means (18, 20, 22), one such local line control means associated with each bus master device (10, 11, 12) for receiving a Bus Acknowledge signal (34) from said bus arbitrator device (16) or from a preceding bus master device, characterized in that said local line control means (18, 20, 22) include means (31, 33) for enabling a Local Bus Request Granted signal (50) without first synchronizing said Bus Acknowledge signal (34) with local bus master control timings.
Claim 2
Independent Claim
141 words
A system for resolving contention among a plurality of asynchronous bus master devices (10, 11, 12) connected to a common bus (13), including a bus arbitrator device (16), means (17, 19, 21) for serially connecting each said bus master device in order of priority with the highest priority bus master device (10) directly connected to said bus arbitrator device (16) and local line control means (18, 20, 22), one such local line control means associated with each bus master device (10, 11, 12) for receiving a Bus Acknowledge signal (34) from said bus arbitrator device (16) or from a preceding bus master device, characterized in that said local line control means (18, 20, 22) include means (31, 33) for enabling a Local Bus Request Granted signal (50) without first synchronizing said Bus Acknowledge signal (34) with local bus master control timings.
Claim 3
Dependent Claim
60 words
The system of claim 1 wherein said local line control means (18, 20, 22) further include synchronization means (41, 41A, 42, 43) for synchronizing said Bus Acknowledge signal (34) with local control before said local line control means (18, 20, 22) is allowed to generate a Bus Acknowledge Pass signal (44) to send to the next downstream bus master device.
Claim 4
Dependent Claim
73 words
The system of claim 2 wherein said local line control means (18, 20, 22) further include inhibiting means (37, 51, 38) for preventing the passage of said Bus Acknowledge signal (34) to the next downstream bus master device for a period of time prior to the local cycle time for issuing a Local Bus Request signal (32), wherein said period of time is sufficient to allow said synchronization means (42, 43) to stabilize.
Claim 5
Dependent Claim
52 words
The system of claim 3 wherein said inhibiting means (37, 51, 38) continues to inhibit the passage of said Bus Acknowledge signal (34) to said next downstream bus master device when said local bus master device issues a Local Bus Request signal (32) and said Bus Acknowledge Pass signal (44) is inactive.
Claim 6
Independent Claim
116 words
The method of connecting control lines for serially connected independent asynchronous bus master devices commonly sharing a single bus to enable a bus master device to seize control of said bus without a synchronization delay, comprising the steps of: receiving a Bus Acknowledge signal from a bus arbitrator in response to a Bus Request signal, said Bus Acknowledge signal indicating that said bus is free, and issuing a Local Bus Request signal to initiate the process of seizing control of said bus if a Bus Acknowledge signal is present and has not been passed to downstream bus master devices, whereby control of said bus is obtained without first synchronizing said Bus Acknowledge signal with local control.
Claim 7
Independent Claim
116 words
The method of connecting control lines for serially connected independent asynchronous bus master devices commonly sharing a single bus to enable a bus master device to seize control of said bus without a synchronization delay, comprising the steps of: receiving a Bus Acknowledge signal from a bus arbitrator in response to a Bus Request signal, said Bus Acknowledge signal indicating that said bus is free, and issuing a Local Bus Request signal to initiate the process of seizing control of said bus if a Bus Acknowledge signal is present and has not been passed to downstream bus master devices, whereby control of said bus is obtained without first synchronizing said Bus Acknowledge signal with local control.
Claim 8
Dependent Claim
29 words
The method of claim 5 further including the step of synchronizing said Bus Acknowledge signal with local control before passing said signal to the next downstream bus master device.
Claim 9
Dependent Claim
32 words
The method of claim 6 further including the step of inhibiting the passage downstream of said Bus Acknowledge signal whenever the local bus master device acts to seize control of said bus.
Claim 10
Dependent Claim
44 words
The method of claim 7 wherein said inhibiting step is initiated a period of time prior to the issuance of a Local Bus Request signal in order to stabilize a signal indicating the state of a previously received and passed along Bus Acknowledge signal.
References Cited (Backward Citations)
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