Transcript
INTEL 8251A INTEL 8251A USARTUSART
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IINTERNAL STRUCTURENTERNAL STRUCTURE
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IInternal structurenternal structure
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IINTERNAL STRUCTURENTERNAL STRUCTURE C/D=1(CONTROL/STATUS)C/D=1(CONTROL/STATUS) =0(DATA)=0(DATA)
C/DC/D RDRD WRWR
00 00 11 DATA BUSDATA BUS
00 11 00 DATA BUSDATA BUS
11 00 11 STATUSSTATUS
11 11 00 CONTROLCONTROL
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INITIALIZATIONINITIALIZATION
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INITIALIZATIONINITIALIZATION MODEMODE WORD WORD
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MODEMODE
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COMMAND COMMAND WORDWORD::
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COMMAND WORDCOMMAND WORD
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COMMAND WORDCOMMAND WORD
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STATUS WORDSTATUS WORD
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INITIALIZATIONINITIALIZATION
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PROGRAMPROGRAM
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RS-232C standardRS-232C standard
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