发明名称 |
System and method for improving LBIST test coverage |
摘要 |
The initialization process and structure of the system ensure that during loading of random data a 1-hot condition is maintained to the 1-hot multiplexer so as to prevent contention or a high current state. The present invention further improves observability of intermediate stages by preventing random data feeding of the state elements in scan chains that cannot tolerate random data. A scan chain having only scan registers that can receive random data is referred to as a LBIST Random Scan Chain (LRSC) and a scan chain having one or more scan registers that cannot tolerate and cannot receive random data is referred to as a "LBIST Non-random Scan Chain" (LNSC). A PRPG generates random data having a plurality of bit values to the LRSCs which is then passed to a multiple input shift register (MISR). The LNSCs do not receive random data from the PRPG but instead receive bit values from another scan chain. Before feeding bit values into a LNSC, the bit values are feed into a decoder and the LNSCs feed bit values reflecting test responses into the MISR. The system may further include recirculation lines in electrical communication with a LNSC to recirculate original bit values back into the LNSC.
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申请公布号 |
US6636997(B1) |
申请公布日期 |
2003.10.21 |
申请号 |
US20000695749 |
申请日期 |
2000.10.24 |
申请人 |
FUJITSU LIMITED |
发明人 |
WONG PAUL;PORTER MARK O.;ELVEY DWIGHT K. |
分类号 |
G01R31/3185;(IPC1-7):G01R31/28 |
主分类号 |
G01R31/3185 |
代理机构 |
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主权项 |
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地址 |
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