Chapter 1: Microprocessor architecture ECE 3120 – Fall 2013 Dr. Mohamed Mahmoud http://iweb.tntech.edu/mmahmoud/
[email protected] Outline 1.1 Computer hardware organization 1.1.1 Number System 1.1.2 Computer hardware organization 1.2 The processor 1.3 Memory system operation 1.4 Program Execution 1.5 HCS12 Microcontroller 1.1.1 Number System - Computer hardware uses binary numbers to perform all operations. - Human beings are used to decimal number system. Conversion is often needed to convert numbers between the internal (binary) and external (decimal) representations. - Octal and hexadecimal numbers have shorter representations than the binary system. - The binary number system has two digits 0 and 1 - The octal number system uses eight digits 0 and 7 - The hexadecimal number system uses 16 digits: 0, 1, .., 9, A, B, C,.., F 1 - 1 - A prefix is used to indicate the base of a number. - Convert %01000101 to Hexadecimal = $45 because 0100 = 4 and 0101 = 5 - Computer needs to deal with signed and unsigned numbers - Two’s complement method is used to represent negative numbers - A number with its most significant bit set to 1 is negative, otherwise it is positive. 1 - 2 1- Unsigned number %1111 = 1 + 2 + 4 + 8 = 15 %0111 = 1 + 2 + 4 = 7 Unsigned N-bit number can have numbers from 0 to 2N-1 2- Signed number %1111 is a negative number. To convert to decimal, calculate the two’s complement The two’s complement = one’s complement +1 = %0000 + 1 =%0001 = 1 then %1111 = -1 %0111 is a positive number = 1 + 2 + 4 = 7.