发明公开
- 专利标题: Testable latch self checker
- 专利标题(中): PrüfbareKippschaltung mitSelbstprüfer。
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申请号: EP90114663.9申请日: 1990-07-31
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公开(公告)号: EP0418521A2公开(公告)日: 1991-03-27
- 发明人: Montoye, Robert Kevin
- 申请人: International Business Machines Corporation
- 申请人地址: Old Orchard Road Armonk, N.Y. 10504 US
- 专利权人: International Business Machines Corporation
- 当前专利权人: International Business Machines Corporation
- 当前专利权人地址: Old Orchard Road Armonk, N.Y. 10504 US
- 代理机构: Jost, Ottokarl, Dipl.-Ing.
- 优先权: US410555 19890920
- 主分类号: G06F11/26
- IPC分类号: G06F11/26 ; G11C29/00
摘要:
The present invention operates by verifying correct latch operation in a digital circuit. After a value has been stored in a latch, electronic circuitry can verify that the value has been stored correctly. The electronic circuitry that performs this verification can be tested to insure that it is operating properly. Several latches can be wired into a scan chain and tested with relative ease. Operation of the present invention is illustrated by an enhanced master-slave latch system. In this system, two comparators are used. A first comparator (308) is used to determine if the internal state of the master latch is identical to the signal which had been applied to this latch's data input terminal (Q₁). A second comparator (310) is used to determine if the state transfer between the master (305) and slave (306) latches occurs properly. Each comparator consists of an EXCLUSVIE-OR function. By placing known logic levels on each input terminal of the comparison circuitry, the output terminal of the comparison circuitry can be examined for an expected logic level to verify that it is operating properly. By placing several latches into a scan chain (719) , a single latch can be loaded with data which will cause an expected signal to appear on the output terminal of this latch's comparison circuitry. This allows for simplified testing of a multiple latch system.
公开/授权文献
- EP0418521A3 Testable latch self checker 公开/授权日:1992-07-15
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