US5146459A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electronic equipment with check-sum function
Assignee: Canon Inc
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Filing: 1991-06-17
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Granted: 1992-09-08
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Expires: 2011-06-17
Abstract
Abstract A data collector, a handy terminal or similar portable electronic equipment with check-sum function, in which circuits for check-sum function are provided separately from the central processing unit, in order to reduce the time required for check-sum procedure.
Inventors
- 👤 Yutaka Shimizu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 04:50
CPC Classifications
G; G06; G06F; G06F11/00; G06F11/07; G06F11/08; G06F11/10; G06F11/1008; G06F11/1076; G06F11/1004
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
165 words
An electronic apparatus with a check-sum function, said apparatus comprising: processing means for processing data; first memory means for storing data to be processed by said processing means; calculating means, independent of said processing means, for calculating a first check-sum value and a second check-sum value of the data stored in said first memory means; instruction means for instructing that power to said apparatus be turned off; first control means for controlling said calculating means to calculate the first check-sum value in response to the instruction that power be turned off; second memory means for storing the first check-sum value; second control means for controlling said calculating means to calculate the second check-sum value whenever power is turned on; comparator means for comparing the first check-sum value stored in said second memory means with the second check-sum value; and discrimination means for determining whether or not the data stored in said first memory means is correct when the first and second check-sum values are compared.
Claim 2
Dependent Claim
165 words
An electronic apparatus with a check-sum function, said apparatus comprising: processing means for processing data; first memory means for storing data to be processed by said processing means; calculating means, independent of said processing means, for calculating a first check-sum value and a second check-sum value of the data stored in said first memory means; instruction means for instructing that power to said apparatus be turned off; first control means for controlling said calculating means to calculate the first check-sum value in response to the instruction that power be turned off; second memory means for storing the first check-sum value; second control means for controlling said calculating means to calculate the second check-sum value whenever power is turned on; comparator means for comparing the first check-sum value stored in said second memory means with the second check-sum value; and discrimination means for determining whether or not the data stored in said first memory means is correct when the first and second check-sum values are compared.
Claim 3
Dependent Claim
20 words
An electronic apparatus according to claim 1, wherein said processing means and said comparator means are included in a CPU.
Claim 4
Dependent Claim
29 words
An electronic apparatus according to claim 1, wherein said first and second control means interrupt said processing means when said calculating means calculates the first and second check-sum values.
Claim 5
Dependent Claim
186 words
An electronic apparatus with a check-sum function, said apparatus comprising: processing means for processing data; first memory means for storing data to be processed by said processing means; calculating means, independent of said processing means, for calculating a first check-sum value and a second check-sum value of the data stored in said first memory means; direct memory access means for transferring the date from said first memory means to said calculating means; instruction means for instructing that power to said apparatus be turned off; first control means for activating said direct memory access means in response to the instruction that power be turned off, to calculate the first check-sum value; second memory means for storing the first check-sum value; second control means for activating said direct memory access means whenever power is turned on, to calculate the second check-sum value; comparator means for comparing the first check-sum value stored in said second memory means with the second check-sum value; and discrimination means for determining whether or not the data stored in said first memory means is correct when the first and second check-sum values are compared.
Claim 6
Dependent Claim
186 words
An electronic apparatus with a check-sum function, said apparatus comprising: processing means for processing data; first memory means for storing data to be processed by said processing means; calculating means, independent of said processing means, for calculating a first check-sum value and a second check-sum value of the data stored in said first memory means; direct memory access means for transferring the date from said first memory means to said calculating means; instruction means for instructing that power to said apparatus be turned off; first control means for activating said direct memory access means in response to the instruction that power be turned off, to calculate the first check-sum value; second memory means for storing the first check-sum value; second control means for activating said direct memory access means whenever power is turned on, to calculate the second check-sum value; comparator means for comparing the first check-sum value stored in said second memory means with the second check-sum value; and discrimination means for determining whether or not the data stored in said first memory means is correct when the first and second check-sum values are compared.
Claim 7
Dependent Claim
20 words
An electronic apparatus according to claim 4, wherein said processing means and said comparator means are included in a CPU.
Claim 8
Dependent Claim
28 words
An electronic apparatus according to claim 4, wherein said direct memory access means interrupts said processing means when said calculating means calculates the first and second check-sum values.
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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) | 1995-09-08 | 1996-03-09 | 1996-09-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-09-08 | 2000-03-09 | 2000-09-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-09-08 | 2004-03-09 | 2004-09-08 | $7700.00 | Window Closed / Lapsed |