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Published byGuadalupe Bridges Modified over 9 years ago
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Memory –Random Access Memory Read/Write, volatile –Read-Only Memory Program, non-volatile Programable ROM Erasable PROM –UV EPROM –Electrical EPROM –Flash memory –Serial EEPROM
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8051 write to 6264 –A0~A12 / 解碼電路 CS –D0~D7 –WR 8051 read from 6264 –A0~A12 / 解碼電路 CS –RD – D0~D7
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READ –1. CS –2. A0-A12 –3. RD –4. D0-D7 WRITE –1. CS –2. A0-A12 –3. D0-D7 –4. WR
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READ –1. CS –2. A0-A12 –3. RD –4. D0-D7 Program
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101x xxxx xxxx xxxx 1010 0000 0000 0000 = A000h 1011 1111 1111 1111 = BFFFh 001x xxxx xxxx xxxx 0010 0000 0000 0000 = 2000h 0011 1111 1111 1111 = 3FFFh
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MOVX @DPTR,A –DPL P0, DPH P2 –ALE –A P0 –WR MOVX A,@DPTR –DPL P0, DPH P2 –ALE –RD –A P0
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000x xxxx xxxx xxxx 0000 0000 0000 0000 = 0000h 0001 1111 1111 1111 = 1FFFh 101x xxxx xxxx xxxx 1010 0000 0000 0000 = A000h 1011 1111 1111 1111 = BFFFh
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Fetch instruction –PC L P0, PC H P2 –ALE –PSEN –Instruction Register P0 MOVC A,@A+DPTR –(DPTR+A) L P0, (DPTR+A) H P2 –ALE –PSEN –A P0
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__data unsigned char test_data; __xdata unsigned char test_data; __xdata __at 0x7ffe unsigned int chksum; __idata unsigned char test_data; __code unsigned char test_code=‘A’; bit test_bit;
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__code __at 0xA000 unsigned char x=‘1’; __xdata __at 0x2000 unsigned char y; y=x;
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__xdata __at 0x3000 unsigned char x[1024]; for(i=0;i<1024;i++) x[i]=i;
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Stack
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110x xxxx xxxx xxxx 1100 0000 0000 0000 = C000h 1101 1111 1111 1111 = DFFFh __xdata __at 0xC000 unsigned char x[8192]; int i; for(i=0;i<8192;<i++) –x[i]=0;
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