Introduction to Digital Systems.pdf.pdfVIP

1Introduction to Digital Systems by Dr. Ahmet ?ZKURT for IZMIR University of ECONOMICS 2006 Based on the notes ofJaeyoung Choi, choi@comp.ssu.ac.kr fall 2000 2/43 Digital Computers and Number Systems 23/43Digital Computers Digital Computers ‘information age’ a prominent and growing role in modern society generality follow a sequence of instruction, called a program, that operates on given data perform a variety of information-processing tasks Digital computer the best-known example of a digital system manipulate discrete elements of information (ex) 10 decimal digits, 26 letters of the alphabets, .... 4/43Digital Computers Signals electrical signals such as voltages and currents two discrete values High (output) 4.5~5.5 (input) 3.0~5.5 Low (output) -0.5~1.0 (input) -0.5~2.0 High Low (H L), True False, 1 0 Binary Number System a binary digit is called a bit information is represented in group of bits use various coding techniques 35/43Digital Computers Computer Structure Figure 1-2: Block Diagram of a Digital Computer 6/43Digital Computers Basic Structure memory unit: stores programs, input, output, data ALU Unit (Arithmetic Logic Unit): performs arithmetic and other dataprocessing operations, as specified by the program control unit: supervises the flow of information between units (CPU = control unit + data path) input device: key board output device: CRT, LCD More FPU (floating-point unit) MMU (memory management unit) (Memory: MMU + internal cache + external cache + RAM) (See Text p.2) 47/43Number Systems decimal number (base 10 or radix 10) 724.5 = 7 x 102 + 2 x 101 + 4 x 100 + 5 x 10-1 In general, AnAn-1....A1A0.A-1A-2....A-m+1A-m Each Ai coefficient is (0, 1, 2, 3, 4, 5, 6, 7, 8, 9) base r or radix r expressed with a power series in r An rn + An-1 rn-1 + .... + A1 r1 + A0 r0 + A-1 r-1 + A-2 r-2 + .… + A-m+1 r-m+1 + A-m r-m expresses in positional notation AnAn-1....A1A0.A-1A-2....A-m+1A-m . is called radix point 8/43Number Systems An is