典型外部RAM如ROM的使用

RAMROM1.189C511RAMROM51I/0ROMRAM12ROMRAM3C51C5112ROM/RAM3ROM/RAM1.21P0DB0-DB78051ALE,ALEP0A7-A0.P28A15-A816P2P08051PSENALEEARSTT0T12/74LS373828274LS27374LS373OEGGG1ROMROMROMPSENROM272562712827642732275122764ROMEPROM(),Kbit276464KEPROM.27647*Vcc+5V*GND*A0-A12D0-D7*OE*CE2ROMP22764CEP02764P0EPROMALEPSEN2764OEP227648CE3RAM1RAMRAMRAMROMRAMRAMEEPROMflashRAMRAMRAMI/O61162K62648K6225632K626462648K*8SRAM*WE:*A0-A9*D0-D7:*OE*CS1*CS22RAM6264P26264CEP06264P0EPROM1.327646264P074LS37374LS3732764A0-A7P0EPROMD0-D7ALE30CLKPSEN292764OE1.ROM--2764ROM*8051*OSC:6MHz*74LS3732764*27648KBEPROM*2764A0-A7Q0-Q78P0*2764A8-A12:P2.0-P2.45*D0-D7P084LS37327648*PSEN29:ROM2764OE*ALE3074LS3732.RAM---6264*8051ROM*OSC6MHz*74LS3732764.ROM*62648KBSRAM.*6264A0-A7Q0-Q78P0*6264A8-A12P2.0P2.45*D0D7874LS3732764ROM8.*P2.562646264CS1*ALE:74LS3731*RC*8051RST9RAMPC0000H2.CPU**S*805166123**XTAL1XTAL2191880518051XTAL2(18)XATL2XTAL2TTL5.1KCHMOSXTAL1XTAL2*TTLTTL2.4V0.4V3.5V0.2=2.0V=0.8V,,0.4VCMOS00VTLLTTL=5V,CMOS=3.3V,TTLTTLCMOSTTL5-10nsCMOs25-50nsCMOS1.4C51805151databdata5164128256512xdataRAM676464KRAMRAMa0x0100H0x0600H#defineaXBYTE[0x0100]#defineaXBYTE[0x0200]#definecXBYTE[0x0300]#definedXBYTE[0x0400]#defineeXBYTE[0x0500]#definefXBYTE[0x0600]