经典IC设计面试问题9
时间：10-02
整理：3721RD
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Casex,z difference,which is preferable,why?
CASEZ :
Special version of the case statement which uses a Z logic value to represent don't-care bits. CASEX :
Special version of the case statement which uses Z or X logic values to represent don't-care bits.
CASEZ should be used for case statements with wildcard don抰 cares, otherwise use of CASE is required; CASEX should never be used.
This is because:
Don抰 cares are not allowed in the "case" statement. Therefore casex or casez are required. Casex will automatically match any x or z with anything in the case statement. Casez will only match z抯 -- x抯 require an absolute match.
CASEZ :
Special version of the case statement which uses a Z logic value to represent don't-care bits. CASEX :
Special version of the case statement which uses Z or X logic values to represent don't-care bits.
CASEZ should be used for case statements with wildcard don抰 cares, otherwise use of CASE is required; CASEX should never be used.
This is because:
Don抰 cares are not allowed in the "case" statement. Therefore casex or casez are required. Casex will automatically match any x or z with anything in the case statement. Casez will only match z抯 -- x抯 require an absolute match.
good information ！
恩，实际有点用
youxie yong ,neng geng xiang xi hui geng hao ,xiexie sir
嗯，谢谢分享
谢谢分享
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