2.0 INTRODUCTIONCapability of processor determine the

capability of the computer system. Therefore, processor is the key element or heart of a computer system.

Other than PC, microprocessors are used in various computerized system such as industrial automation.

2.1 EVOLUTION OF MICROPROCESSORNumber of bits μP can handle at any one

time determined the capacities of μP.Improvement number of bits determined by

2n . Manufacturer/Year

INTEL MOTOROLA

1971 4004, 4 bit, 108 kHz, contains 2300 transistors

6800, 8 bit

1979 8088, 8 bit, 2 MHz, contains 29000 transistors

68000, 16 bit

1982 80286, 16 bit, 8-12 MHz, contains 80286 transistors

68020, 32 bit

1985 80386, 32 bit, 16-20 MHz, contains 275000 transistors

68030, 32 bit

1989 80486, 32 bit, 25-66 MHz, contains 1.2 million transistors

68040, 32 bit

1993 Pentium, 64 bit, 60-166 MHz, contains 3.1 million transistors

68060, 64 bit

1997 Pentium II, 300 MHz::

2.1 EVOLUTION OF MICROPROCESSORM68000 FAMILYComparative of various M68000 family µP.

All chips have 32 bit CPU register, but the early µP are 16 bit systems.

Why Motorola built 68008 (8 bit) after 68000 (16 bit)?

2.2 DATA SIZECapacity of µP:

Bits of data – size of data bus memory size accessible – size of address bus

Data size – data stored in a single cell of memory. (size of data bus determine the data size)1 bit : the smallest.4 bit : nibble.8 bit : byte.16 bit : word.32 bit : long word.

Data sizen

Data type Data capacity2n

Range

1 Bit 2 0 – 14 Nibble 16 0 - 158 Byte 256 0 – 25516 Word 65536 0 – 6553532 Long Word 4,294,967,296 0 - 4,294,967,295

2.2 DATA SIZE (cont.)

2.3 BLOCK DIAGRAM OF A BASIC COMPUTER SYSTEM

Tocci, 1991A digital comp is a combination of digital devices

and circuits that can perform a programmed sequence of operations (program) with a minimum of human intervention.

Program is a set of coded instructions, stored in the comp’s internal memory executed by the computer in order.

Comp do not think but high speed machine that can manipulate data, solve problems and make decision, all under control of the program.

Basic computer system

Basic Microcomputer system

Microcomputer system with Intel 8085 microprocessor

Microcomputer system with Motorola 68000 microprocessor

2.4 BUS SYSTEMA wire used to transfer a signal from one point

to another.

2.4 BUS SYSTEM (cont.)Data bus – bidirectional (read or write).

Determine the data size. Transfer data in parallel.

2.4 BUS SYSTEM (cont.)Address bus – unidirectional. Transfer data in

parallel. Determine the number of memory cells (lines).

Control bus – bidirectional (not the same line). set of signals used to synchronize the activities of the separate microcomputer element.Ex : Read, WriteEx : RESET, INTR

2.5 OPERATION OF COMPUTER SYSTEM

How computer system works?ROM permanently stores a short program

(initial).When comp is ON, CPU read program in ROM

1. reset connected devices to standby mode.2. transfer system programs (OS) from permanent storage (hard disk) to RAM.3. System program will provide needs for user.

2.5 OPERATION OF COMPUTER SYSTEM (cont.)Fetch & execute cycle

2.5 OPERATION OF COMPUTER SYSTEM (cont.)Fetch cycle – a, b, cExecute cycle – e

2.5 OPERATION OF COMPUTER SYSTEM (cont.)Example 2-1 (page 28)

2.5 OPERATION OF COMPUTER SYSTEM (cont.)Read in fetch cycle

2.5 OPERATION OF COMPUTER SYSTEM (cont.)Write in execute cycle

2.6 INTERNAL STRUCTURE & BASIC OPERATION OF MICROPROCESSORMicroprocessor packaged in IC chip.The pins configuration / block diagram used to

explain or analyze the architecture of a microprocessor.

Figure 2.12 – Intel 8085 microprocessor chipFigure 2.13 – Motorola 68000 microprocessor

chip

2.6 INTERNAL STRUCTURE & BASIC OPERATION OF MICROPROCESSORInternal structure

µP consist of :1. control & timing – fetch cycle, decode, execute cycle.

supply clock / timing.2. register – temporary.

faster than memory. Various types.

3. ALU – arithmetic & logic operation.

2.6 INTERNAL STRUCTURE & BASIC OPERATION OF MICROPROCESSORTherefore, µP performs a number of functions,

includes:Providing timing and control signal.Fetching instruction and data.Decoding instruction.Transferring data between I/O and memory.Performing A&L operation.Responding to I/O-generated control signal

such as RESET or INTERRUPT.

2.6 INTERNAL STRUCTURE & BASIC OPERATION OF MICROPROCESSORRegister set (32 bit)

8 data register7 address register 2 stack pointer1 program counter1 status register

2.7 MICROPROCESSOR CLOCK SYSTEM• Intel 8085 clock system and bus cycle timing

2.7 MICROPROCESSOR CLOCK SYSTEM (cont.)

2.7 MICROPROCESSOR CLOCK SYSTEM (cont.)• Motorola 68000 clock system and bus cycle

timing• Bus cycle (machine cycle)Instruction No. of

Read cycleNo. of

Write cycle

MOVE.L D2,D3 1 0MOVE.W 34(A1),D2 3 0MOVE.B D3,60(A2) 2 1ADD.L 56(A3),D4 4 0ADD.L D4,56(A3) 4 2ADDI.W #$1234,56(A3) 4 1JMP XXXX.W 2 0JSR XXXX.W 2 2TRAP #5 4 3

2.7 MICROPROCESSOR CLOCK SYSTEM (cont.)