US5042003A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Memory usage system
Assignee: NEC Corp
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Filing: 1988-07-06
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Granted: 1991-08-20
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Expires: 2008-07-06
Abstract
Abstract An improved means and method for expanded memory system access and control is disclosed. A logic array in the expanded memory control circuitry which accesses and controls up to two separate expansion boards through the use of static random access memory as register circuits and octal buffers for addressing. The control and access method implemented through a state machine in the logic array provides the operation of the improved expanded memory system to control additional expansion boards and to access the appropriate memory locations.
Inventors
- 👤 Steve L. Belt
- 👤 Robert A. Kohtz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 16:57
CPC Classifications
G; G06; G06F; G06F12/00; G06F12/02; G06F12/06; G06F12/0615; G06F12/0623
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
111 words
A method for expanded memory usage comprising: recognizing an expanded memory access request; testing a first memory board enable signal; accessing a first memory board if said enable signal has a first state; and accessing a second memory board if said enable signal has a second state; as well as: detecting an input/output request signal; testing said first memory board enable signal; accessing said first memory board for input/output if said first memory board enable signal has a first memory board enable signal has a second state; further including: introducing a wait state prior to said second memory board input/output if said first memory board enable signal has said second state.
Claim 2
Independent Claim
111 words
A method for expanded memory usage comprising: recognizing an expanded memory access request; testing a first memory board enable signal; accessing a first memory board if said enable signal has a first state; and accessing a second memory board if said enable signal has a second state; as well as: detecting an input/output request signal; testing said first memory board enable signal; accessing said first memory board for input/output if said first memory board enable signal has a first memory board enable signal has a second state; further including: introducing a wait state prior to said second memory board input/output if said first memory board enable signal has said second state.
Claim 3
Independent Claim
78 words
A method for expanded memory usage comprising: recognizing an expanded memory access request; ascertaining whether said expanded memory access request is valid; returning to an idle state to await a subsequent expanded memory access request if said expanded memory access request is not valid. testing a first memory board enable signal; accessing a first memory board if said enable signal has a first state; and assessing a second memory board if said enable signal has a second state.
Claim 4
Independent Claim
78 words
A method for expanded memory usage comprising: recognizing an expanded memory access request; ascertaining whether said expanded memory access request is valid; returning to an idle state to await a subsequent expanded memory access request if said expanded memory access request is not valid. testing a first memory board enable signal; accessing a first memory board if said enable signal has a first state; and assessing a second memory board if said enable signal has a second state.
Claim 5
Independent Claim
86 words
A method for expanded memory usage comprising: recognizing an expanded memory access request; testing a first memory board enable signal; accessing a first memory board if said enable signal has a first state; accessing a second memory board if said enable signal has a second state; ascertaining whether said expanded memory access request is directed to the first or second memory boards; and p1 returning to an idle state if said expanded memory access request is not directed to said first or said second memory board.
Claim 6
Independent Claim
86 words
A method for expanded memory usage comprising: recognizing an expanded memory access request; testing a first memory board enable signal; accessing a first memory board if said enable signal has a first state; accessing a second memory board if said enable signal has a second state; ascertaining whether said expanded memory access request is directed to the first or second memory boards; and p1 returning to an idle state if said expanded memory access request is not directed to said first or said second memory board.
References Cited (Backward Citations)
US4346441A
Cited
US4481570A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-08-19 | 1995-02-18 | 1995-08-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-08-19 | 1999-02-18 | 1999-08-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-08-19 | 2003-02-18 | 2003-08-20 | $7700.00 | Window Closed / Lapsed |