Patent US5313595A successfully refreshed from Google Patents.
US5313595A
Expired / Lapsed
US
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Automatic signal termination system for a computer bus
Assignee: Hewlett Packard Development Co LP
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Filing: 1992-12-10
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Granted: 1994-05-17
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Expires: 2012-12-10
Abstract
Abstract An automatic termination system for an end terminated bus especially useful with the SCSI bus. When utilized with a computer device, for example, a storage subsystem, configuration or reconfiguration of the bus can be automatically effectuated without concerns for inappropriate signal termination of the bus. The invention comprises a circuit which determines if any additional devices have been coupled to the bus and enables an active terminator chip if none is detected. Should another device be coupled onto the bus, the active terminator chip is automatically disabled.
Inventors
- 👤 Mark S. Lewis
- 👤 Ronald R. Ravey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 08:29
CPC Classifications
H; H03; H03H; H03H11/00; H03H11/02; H03H11/28; H03H11/30; G; G06; G06F; G06F13/00; G06F13/38; G06F13/40; G06F13/4063; G06F13/4068; G06F13/4072; G06F13/4077
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
164 words
An automatic termination system for a computer bus having n devices coupled thereto, comprising: a first signal terminator associated with a first end of said bus; a second signal terminator associated with a second end of said bus, said second signal terminator being operative to selectively achieve either one of a first signal termination state in which signal lines of said bus are terminated and a second termination disconnect state in which said signal lines of said bus are not terminated; and means connected to said second signal terminator for automatically detecting an n+1 device coupled to said bus at said second end thereof and in response to the detection of the n+1 device controlling said second signal terminator to transition from said first signal termination state to said second termination disconnect state and for controlling said second signal terminator to transition from said second termination disconnect state to said first signal termination state when said n+1 device is not coupled to said bus.
Claim 2
Dependent Claim
164 words
An automatic termination system for a computer bus having n devices coupled thereto, comprising: a first signal terminator associated with a first end of said bus; a second signal terminator associated with a second end of said bus, said second signal terminator being operative to selectively achieve either one of a first signal termination state in which signal lines of said bus are terminated and a second termination disconnect state in which said signal lines of said bus are not terminated; and means connected to said second signal terminator for automatically detecting an n+1 device coupled to said bus at said second end thereof and in response to the detection of the n+1 device controlling said second signal terminator to transition from said first signal termination state to said second termination disconnect state and for controlling said second signal terminator to transition from said second termination disconnect state to said first signal termination state when said n+1 device is not coupled to said bus.
Claim 3
Dependent Claim
15 words
The automatic termination system of claim 1 wherein said computer bus comprises a SCSI bus.
Claim 4
Dependent Claim
17 words
The automatic termination system of claim 1 wherein said second signal terminator comprises an active terminator chip.
Claim 5
Dependent Claim
36 words
The automatic termination system of claim 1 wherein said detecting means comprises means for checking a portion of said computer bus for a low impedance level ground when said n+1 device is coupled to said bus.
Claim 6
Dependent Claim
16 words
The automatic termination system of claim 4 wherein said checking means comprises a semiconductor switching device.
Claim 7
Dependent Claim
23 words
The automatic termination system of claim 1 wherein said second signal terminator and said detecting means further comprise a mass storage expansion system.
Claim 8
Dependent Claim
87 words
A signal terminator for a computer bus having a number of devices coupled thereto comprising: singal termination means for connection to the bus and operative between a first signal termination state and a second termination disconnnect state thereof; and means operatively controlling said signal termination means for automatically detecting an additional device coupled to said bus so that said signal termination means will transition from said first signal termination state to said second termination disconnect state thereof if said additional device is detected by said detecting means.
Claim 9
Dependent Claim
87 words
A signal terminator for a computer bus having a number of devices coupled thereto comprising: singal termination means for connection to the bus and operative between a first signal termination state and a second termination disconnnect state thereof; and means operatively controlling said signal termination means for automatically detecting an additional device coupled to said bus so that said signal termination means will transition from said first signal termination state to said second termination disconnect state thereof if said additional device is detected by said detecting means.
Claim 10
Dependent Claim
14 words
The signal terminator of claim 7 wherein said computer bus comprises a SCSI bus.
Claim 11
Dependent Claim
16 words
The signal terminator of claim 7 wherein said signal termination means comprises an active termination chip.
Claim 12
Dependent Claim
35 words
The signal terminator of claim 7 wherein said detecting means further comprises means for checking a portion of said computer bus for a low impedance ground when said additional device is coupled to said bus.
Claim 13
Dependent Claim
13 words
The signal terminator of claim 7 further comprising a mass storage expansion system.
Claim 14
Dependent Claim
140 words
A computer device for coupling to a computer bus, said computer bus requiring signal termination at opposite ends thereof, said computer device including an input portion for coupling said computer device to said computer bus at one of said ends thereof and an output portion for discretionary coupling of an additional computer device to said computer bus wherein the improvement comprises: means coupled to said output portion for automatically detecting the coupling of said additional computer device to said output portion of said computer device; and means operative in response to said detecting means for providing signal line termination for said computer bus when said additional computer device is not coupled to said output portion of said computer device and providing no signal line termination when said additional computer device is coupled to said output portion of said computer device.
Claim 15
Dependent Claim
140 words
A computer device for coupling to a computer bus, said computer bus requiring signal termination at opposite ends thereof, said computer device including an input portion for coupling said computer device to said computer bus at one of said ends thereof and an output portion for discretionary coupling of an additional computer device to said computer bus wherein the improvement comprises: means coupled to said output portion for automatically detecting the coupling of said additional computer device to said output portion of said computer device; and means operative in response to said detecting means for providing signal line termination for said computer bus when said additional computer device is not coupled to said output portion of said computer device and providing no signal line termination when said additional computer device is coupled to said output portion of said computer device.
Claim 16
Dependent Claim
40 words
The computer device of claim 12 wherein said detecting means is responsive to a low impedance level ground on a portion of said computer bus when said additional computer device is coupled to said output portion of said computer device.
Claim 17
Dependent Claim
15 words
The computer device of claim 13 wherein said detecting means comprises a semiconductor switching device.
Claim 18
Dependent Claim
17 words
The computer device of claim 12 wherein said signal termination providing means comprises an active terminator chip.
Claim 19
Dependent Claim
14 words
The computer device of claim 12 wherein said computer bus comprises a SCSI bus.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-05-16 | 1997-11-15 | 1998-05-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-05-16 | 2001-11-15 | 2002-05-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-05-16 | 2005-11-15 | 2006-05-17 | $7700.00 | Window Closed / Lapsed |