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25 Cards in this Set
- Front
- Back
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nibble
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a collection of bits on a 4 bit boundary
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It takes four bits
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to represent a single BCD or hexidecimal digit
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byte
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consists of 8 bits and is the smallest addressable datum (data item) in the microproccor
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Main memory and I/O addresses in the PC
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are all byte addresses
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the bits in a byte
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are numbered from bit zero (b0) through seven (b7)
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Bit 0
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is the low order bit or least significant bit
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bit 7
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is the high order bit or most significant bit of the byte
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the rightmost bit in a binary number
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is bit postition zero
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byte values
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require two hexidecimal digits
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byte contains
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8 bits, it can represent 2^8, or 256 different values
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the PC
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is a byte addressable machine
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most important use for a byte
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is holding a character code
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ASCI character set
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there are 128 defined codes in it
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boundary for a WORD
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is defined as either 16-bits or the size of the data bus for the processor
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double word
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two words
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For Inted CPUs,
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a word is a group of 16-bits
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In a word
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like the byte, bit 0 is the LSB and bit 15 is the MSB
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a word contains exactly
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two bytes
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3 major uses for words
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16-bit interger data values, 16-bit memory addresses, and any number system requiring 16 bits or less
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double word quantity
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is 32 bits
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Larger CPUs such as the Pentium will
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use double words when pulling data for memory
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bit zero
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is usually referred to as the
the LSB |
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hexidecimal System
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uses 16 digits and thus the base 16
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add "h"
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in the end of a hexidecimal number
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hexidecimal #'s that begin with a letter (A....F)
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We add "0" at the beginning
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