單片機第七章MCS-51單片機擴展存儲器的設(shè)計

1、圖圖 7 - 1P2.0P2.1P2.2P2.3P0.0P0.1P0.2P0.3P0.4P0.5P0.7P0.61817141387431916151219652234567821192223171615141311109202930242322213233343536373839111D7D6D5D4D3D2D1D0Q7Q6Q5Q4Q3Q2Q1Q0A11A10A9A8A7A6A5A4A3A2A1A0O7O6O5O4O3O2O1O0OE/VPPALEPSENG OEGNDGND2412 18VCC GND CEEA31GND803127324K874LS373 5 V圖圖 7 - 2A71A6

2、2A53A44A35A26A17A08O09O110O211GND12O313O414O515O616O717CE18A1019OE/VPP20A1121A922A823VCC242732圖圖 7 - 37 - 3其中，A0A11為地址線；O0O7為數(shù)據(jù)線； CE為片選線；OE/VPP為輸出允許/編程高壓。 除了12條地址線和8條數(shù)據(jù)線之外，CE為片選線，低電平有效。也就是說，只有當CE為低電平時，2732才被選中，否則，2732不工作。OE/VPP為雙功能管腳，當2732用作程序存儲器時，其功能是允許讀數(shù)據(jù)出來；當對EPROM編程（也稱為固化程序）時，該管腳用于高電壓輸入，不同生產(chǎn)廠家的芯片

3、編程電壓也有所不同。當我們把它作為程序存儲器使用時，不必關(guān)心其編程電壓。A71A62A53A44A35A26A17A08I/O09I/O110I/O211GND12I/O313I/O414I/O515I/O616I/O717CE18A1019OE20WE21A922A823VCC246116圖圖 7 - 47 - 4P2.0P2.1P2.2P2.7P0.0P0.1P0.2P0.3P0.4P0.5P0.7P0.6181714138743191615121965223456781819222317161514131110930282322213233343536373839111D7D6D5D4D

4、3D2D1D0Q7Q6Q5Q4Q3Q2Q1Q0CEA10A9A8A7A6A5A4A3A2A1A0I/O7I/O6I/O5I/O4I/O3I/O2I/O1I/O0ALEG OEGND2412VCC GNDGND803161162K874LS373WEWR1627 5 VRD1722 OE圖圖 7 - 57 - 5D7Q7Q0D074HC373A12A11A10A9A8CEA7A0D7 D0 OEP2.7P2.6P2.5P2.4P2.3P2.2P2.1P2.0ALEP0PSENWRRD80C51IC02764IC02764D0 OECEA12A11A10A9A8A7A0D7IC02764D0 OE

5、CEA12A11A10A9A8A7A0D7 D0 OECEA12A11A10A9A8A7A0D7A8A9A10A11A12A8A9A10A11A12A8A9A10A11A12A12A11A10A9A8IC12764D0D0D0D0D7D7D7D7OEOEOEOEA0A0A0A0A7A7A7A7A0A0A0A0A7A7A7A7A8A8A8A8A9A9A9A9A10A10A10A10OEOEOEOECECECECEA11A11A11A11A12A12A12A12A10A10A10A10A0A0A0A0OEOEOEOEA7A7A7A7A8A8A8A8A9A9A9A9A12A12A12A12A11A11