1. 1.21 Introduction to microprocessors KUEU 2135 / KBEB 2193 Mikropemproses dan Sistemnya

2. 2.21 Brief history 1940s – vacuum tubes  high current + heat 1947 – transistor (Bell Labs)  low current + heat + smaller size 1950s – semiconductor (Texas Instruments)  integrated circuits born. From SSI to VLSI Manufacturers compete – Motorola, Intel MC6809 – most advanced 8-bit, has some 16-bit operations built-in

3. 3.21 A microprocessor Current  p more advanced than 8-bit; but architecture remains Performs arithmetic and logic operations Receives digital input  process according to stored program  (variable) digital output (cf. ICs) Two main parts: arithmetic unit (AU) + control unit (CU)

4. 4.21 A microprocessor (cont’d.) Arithmetic unit made up of: –Arithmetic Logic Unit (ALU) – arithmetic calculations + logic operations –Accumulators (ACC) – where arithmetic calculations are made –Condition Code Register (CCR) – set based on results of ALU; 4 common bits: Zero, Negative, Overflow, Carry

5. 5.21 A microprocessor (cont’d.) Control unit made up of: –Memory Address Register (MAR) – holds current address where  p is accessing –Memory Data Register (MDR) – holds instruction temporarily –Instruction Register (IR) – holds fetched instruction  decoder circuitry –Program Counter (PC) – holds next instruction address –Control Logic (CL) – synchronisation

6. 6.21 Arithmetic UnitControl Unit CCR ACC ALU CL IR MDR MAR PC Main memoryInput/Output Microprocessor

7. 7.21 Microcomputer system  p + memory + i/o chips =  computer system –Memory devices – store program, data –I/O devices – read input and/or display results Connected via buses. 3 types: –Address (16-bit, unidirectional) –Data (8-bit, bidirectional) –Control (variable) e.g. Read, Write, Enable

8. 8.21 Microcomputer system MPU ROM (program) RAM (data) PROGRAMMABLE I/O Control lines 16-bit address bus 8-bit data bus

9. 9.21 Microcomputer system Memory devices –2 types: ROM and RAM –ROM – permanent information; non-volatile –RAM – temporary data storage; volatile e.g. writing programs

10. 10.21 Microcomputer system Input/output devices –Input device – provide interface between  p and external unit (e.g. ADC, sensors) –Registers to read data before send to  p –Output device – transfer data from  p to external unit (e.g. printers, LEDs) –Some ICs function as input/output device

11. 11.21 Bus interfacing Memory and I/O devices share common buses –Conflict (aka bus contention) occurs when several devices are enabled at the same time Solution: –Disconnect registers using devices with 3- state outputs and/or chip select pins –Overriding ‘read’ register

12. 12.21 Bus interfacing

13. 13.21 Machine language Uses binary or hexadecimal numbers to represent: –Instruction code –Data –Address Need to be familiar with instruction codes for particular  p

14. 14.21 Assembly language Assigns name to instruction code – combination of 3 or 4 alphabets to represent instruction codes Need to be familiar with registers, addressing modes and instruction sets for particular  p Not portable – each  p has own assembly language

15. 15.21 Machine language Assembly language

16. 16.21 High level language (almost) Similar to human language (English?) Don’t need to be familiar with registers, addressing modes and instruction sets Each statement correspond to several assembly language instructions  converted to machine language (aka object code) via assembler/compiler

17. 17.21 Assembly / high-level language Assembler / compilerMachine language

18. 18.21 Assembly / high-level language Assembler / compilerMachine language printf(“Sum is %d”, 3 + 2); high level language LDAA#$03 ADDA#$02 assembly language 86 03 8B 02

19. 19.21 Review questions What is a microprocessor? What are its typical components? What is a bus contention? Name the types of memory in a  computer system