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3????????
????????????????о???????????о??У?74LS139???2??4??????????74LS138??3??8????????????????CMOS??о??????74HC139??74HC138??74LS138???1?????
?1 74LS138о?
74LS138???????????????????????????????????????2?????
?2 74LS138??????? ????EEPROM??????
??2764?????????洢??????????????????2764?????8K??8λ????????????????????洢???????+5V???磬?????????100mA?????????50mA?????????????250ns??2764????????28???????о????????8K??8λ??????????3??
2764?????????????????洢??????????????????????????????????????
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?3 2764????? ?4 2764????
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??1???????????????????2764?????????8K??2=16K????Ч?????
??2764??13?????????????P0.0~P0.7??P2.0~P2.4????????P2.5~P2.7??????????2?2764????????????????P2.5~P2.7?е??κ?2??????????????????в???P2.5?? P2.6????????????????????2??о???????????Χ??
????δ???????0????2764??1????????????Χ??4000H~5FFFH??
????δ???????0????2764??2????????????Χ??2000H~3FFFH??
?5 ????????
??2????EPROM2764???????24KB??????????洢???????74LS138????????24KB????????8000H???????
??????1??2764о???8KB???????????24KB?????洢??????3??2764о????????????????????洢??????????????????????????8000H?????????
2764??1????????????Χ??8000H~9FFFH??
2764??2????????????Χ??A000H~BFFFH??
2764??3????????????Χ??C000H~DFFFH??
???3??о????λ?????A15~A13????????74LS138????????????????????????????2???????3??2764о?????ν?Y4??Y5??Y6???????????·????6??
?6 ???????
????admin ?????????2018-05-08
