SEE 3223 : Microprocessors

1. SEE 3223: Microprocessors Consultation: Tuesday 11:00 – 12:55 a.m. Thursday 11:00 – 12:55 a.m.

2. Module 0 Introduction

3. Microprocessor SEE3223 Aim This subject introduces the principle and the usage of microprocessor. Few topics that are emphasized are processor architecture, assembly language and basic interfacing in a microprocessor-based systems. • Learning Outcomes • At the end of this course, students will be able to : • Describe and differentiate all the component of microprocessor- based systems. • Analyze and design AVR Atmega32 assembly language programs. • Analyze and design AVR Atmega32 microprocessor systems. • Work with AVR Studio and communicate effectively in a team to solve complex AVR Atmega32 design problems.

4. What’s in this course: Assembly language programming Microprocessor concepts Hardware interfacing Pre-Requisites Number representation, coding, registers, state machines Realization of simple logic circuits Integrated circuit technologies Designing with MSI components Flip-Flops Counters and sequential MSI components Register transfer logic SEE3223 Microprocessor Systems

5. Course Policy • Attendance is compulsory. • You are responsible for whatever is taught in the lecture. If you miss a class, it is your responsibility to find out about assignment, quizzes and exam from elearning. • Punctuality is expected. • Makeup quizzes will not be given except in the case of actual emergencies with written evidence. • You are encouraged to collaborate (not copy) on assignment problems with your "study buddies.”

6. Grading Policy Assessment Breakdown: • 4 Quizzes x 10% = 30% • 1 Group Assignment = 20% • Final = 50%

7. Material • Lecture notes Will be posted • Textbooks Muhammad Ali Mazidi and, Sarmad Naimi and Sepehr Naimi(2010), The AVR Microcontroller and Embedded Systems: Using Assembly and C, 1st Ed., Prentice Hall.

8. Module 1 Microprocessor-Based Systems

9. Microprocessor-Based Systems • Aims • To review the main elements of a microprocessor system. • Intended Learning Outcomes • At the end of this module, students should be able to: • Define and explain important terms associated with both hardware and software elements of a microprocessor system • Tell the difference between general purpose computing and embedded computing • List down the major components inside a computer & processor • Tell the difference between computer, processor, microprocessor and microcontroller • Explain instruction execution cycles of a generic microprocessor

10. Computer What is Computer ? Data Processing Data Storage

11. Basic Functions of Computer Data Processing Data Storage Data Movement Control

12. Microprocessor-Based Systems Whenever the word microprocessor is mentioned, it conjures up a picture of a desktop or laptop PC running an application such as a word processor or a spreadsheet. While this is a popular application for microprocessors, it is not the only one and the fact is most people use them indirectly in common objects and appliances without realizing it. Without the microprocessor, these products would not be as sophisticated or cheap as they are today. 20102011-I

13. Microprocessor-Based Systems Computing systems are everywhere. Its probably no surprise that millions of computing systems are built every year destined for desktop computers (Personal Computers, or PCs), workstations, mainframes and servers. What may be surprising is that billions of computing systems are built every year for a very different purpose: they are embedded within larger electronic devices, repeatedly carrying out a particular function, often going completely unrecognized by the devices user. Creating a precise definition of such embedded computing systems, or simply embedded systems, is not an easy task. 20102011-I

14. Computer Classifications • Classification of computers: • Servers: • Big, expensive, available 24x7 (read “24 by 7” or 24 hours a day, 7 days a week. Mainframes are old servers made by IBM. • Desktops: • computers on your desk • Laptops: • computers you carry in your bag • PDA (personal digital assistants): • computers you carry in your pocket • Embedded systems: • computers that don’t look like computers! • An embedded system is a type of computer

15. What is an Embedded System? An embedded system is a microprocessor-based system that is built to control a function or range of functions and is not designed to be programmed by the end user in the same way that a PC is. An embedded system is a special-purpose computer system designed to perform certain dedicated functions. It is usually embedded as part of a complete device including hardware and mechanical parts 20102011-I

16. Embedded System: Example Embedded microprocessors are more deeply ingrained into everyday life than any other electronic circuit that is made. A car may have over 50 microprocessors controlling functions such as the engine through engine management systems, brakes with electronic anti-lock brakes, transmission with traction control and electronically controlled gearboxes, safety with airbag systems, electric windows, air-conditioning and so on. 20102011-I

17. Other Processors in Embedded Systems • Embedded Controllers: • More powerful (32 bits) than microcontrollers (8 bits) • Normally contains only processor and input/output, memory is external • Digital Signal Processors: • Embedded processors optimized for digital signal processing • Commonly found in hand-phones, modems, communications systems • Graphics Processors: • Very powerful processors found in graphics cards of workstations • Programmable Logic Controllers: • Microprocessor boards usually found in industrial applications

18. General Purpose Computing vs Embedded Systems

19. To design a µP System, we must know… • Fundamentals: • What’s inside a computer • What’s inside a processor • Programming: • What happens in the processor when it’s running a program • What do we need to write a program • How to create a program • How to run a program • How to fix a program error • Hardware design: • Timing diagrams • Interfacing with other chips

20. A Computer System – Simplified View 20112012-I

21. A Computer System – Simplified View Moves data between the computer and its external environment Stores and retrieves data CPU Memory Input/Output Controls the operation of the computer Performs its data processing functions Provides communication among CPU, main memory and I/O Address bus Data bus Control bus An embedded system also has the same structure but at a smaller size

22. CPU What is Microprocessor ? Central Processing Unit (CPU): Control the operation of the computer and performs its data processing functions; often simply referred to as PROCESSPR

23. Processor or Central Processing Unit (CPU)

24. Processor (CPU): Control Unit (CU) The Central Processing Unit (or P) To synchronize and control the overall operation of the P system To decode instruction and pass the necessary control signals to CU Control Unit & Instruction Decoder To perform the arithmetic and logical operations within the CPU Arithmetic/Logic Unit A set of internal storage locations within the CPU Registers

25. Processor (CPU): Registers Control & Instruction Registers User-Visible Registers Program Counter General-Purpose Reg. Instruction Register Address Register ... Data Register ... Flag Register

26. Microprocessor – Basic concept CPU 16-bit / 32-bit / 64-bit wide Address bus bidirectional8-bit / 16-bit / 32-bit / 128-bit Data bus Timing signals, ready signals,interrupts etc Control bus Microprocessor, by-itself, completely useless – must have external peripherals to Interact with outside world

27. Microprocessor – Basic concept CPU Address Control BootROM Used at startup Instruction(program)ROM Data RAM Trans- ducers KeyboardScreenUARTParallelinterface etc Data Microprocessor, by-itself, completely useless – must have external peripherals to Interact with outside world

28. 1 2 3 4 5 6 7 8 1 byte = 8-bit data 1 word= 2 bytes 1 double = 2 words Memory Address-n  Memory Location-n Memory Memory Location-1 Memory Address-1  Memory Address-2  Memory Location-2 Number of addresses 2N (where N is an integer)

29. Memory Devices • Read-Only Memory • Non-volatile memory: contents is retained even without power • In embedded systems, used to store application programs and test routines • Contents can be set by fixing it during manufacturing or “burning” it using a programming device • Common types include MROM, PROM, EPROM and flash memory • Erasable types can only be rewritten a fixed number of times • Random Access Memory • Contents lost without power (volatile memory) • Used to store temporary data. In embedded system, very little RAM is required. Some systems don’t even have RAM at all! • No limit to number of writes the device can handle • Fast writes (unlike EPROM/EEPROM) • Two major types are SRAM and DRAM

30. Data & Address Buses Smallest transferable amount of data from memory to CPU (and vice versa) is one byte. Each byte has a unique location or address. The address of each byte is written in hexadecimal (hex). For AVR, the prefix ‘0x’ means a hex value. The range of addresses accessible by the processor is the memory space. (Limited by the size of the address bus). TheAtmega32(and many other AVRmodels)does not have direct support for an external memory interface. CPU Memory 24-bit address bus 16-bit data bus Data bus 16 bits 15 0 0x000000 Address bus 24 bits 24 2 -1= 8M locations 0xFFFFFF

31. Microcontroller – Basic concept 20112012-I

32. Microcontroller – Basic concept CPU Address Control Boot ROM Program ROM Data RAM Trans- ducers Some I/O Data Microcontroller - put a limited amount of most commonly used resources inside one chip

33. Microprocessor vs Microcontroller No matter what is the system size, the most important component is still the processor. • Microcontroller: • A chip that contains all the components of a computer – processor, memory and input/output • Less flexibility • Less component count in system • Less powerful • Microprocessor: • A chip that contains only the processor • Need other chips to make a working system • More flexible • Can have very few I/O or many I/O devices using the same processor chip

34. Software • Computer software • Computer programs are known as software • Program: • Sequence of instructions that perform a task • Instruction: • The simplest operation performed by the processor • Think of it as a note coming from a musical instrument • How the computer works: • Fetch an instruction from memory • Decode the instruction • Execute the instruction • Repeat

35. Machine & Assembly Language • Machine instruction • A sequence of binary digits which can be executed by the processor, e.g. 0001 1011. • Hard to understand for human being • Assembly language • An assembly program consists of assembly instructions • An assembly instruction is a mnemonic representation of a machine instruction e.g. MUL may stand for “multiply” • Assembly programs must be translated into object code before it can be executed -- translated by an assembler. • Assemblers can be of two types: cross assembler and native assembler. • Cross assembler runs on one computer and generates machine instructions that will be executed by another computer that has different instruction set, e.g. freeware ASM68K. • Native assembler runs and generates instructions for the same computer. • Drawbacks of assembly programs are: • dependent on hardware organization, difficult to understand long programs, low programmer productivity

36. High-level language (HLL) • High-Level Language • Syntax of a high-level language is similar to English • A translator is required to translate the program written in a high-level language into object code -- done by a compiler. • There are cross compilers that run on one computer but translate programs into machine instructions to be executed on a computer with a different instruction set. • Main drawback is slower execution speed of the machine code obtained after compiling an HLL program. • However, C language has been extensively used in microcontroller programming in industry.

37. Instruction Cycle (Fetch-Execute) Fetch Execute The processor executes instructions one-by-one according to the sequence found in memory Everything is controlled by, what else, the control unitin the CPU. To execute an instruction, the processor must fetch it from memory. The complete steps the processor takes to execute one instruction is the instruction cycle or thefetch-execute cycle

38. Instruction Cycle Details • On program start: 0. Load the program counter (PC) with the address of the first instruction • Fetch phase: 1. Read the instruction and put it into the instruction register (IR) 2. Control unit decodes the instruction; updates the PC for the next instruction • Execute phase: 3. Find the data required by the instruction. 4. Perform the required operation. 5. Store the results. 6. Repeat from Step 1.

39. Instruction Cycle 1-39

40. A B C D registers How computers work A [17] B  A A  [6] AA+B [7]A 31h C4h 26h 81h EAh 0h 5h 0 1 2 3 4 5 6 7 CPU Logic circuit Address bus Data bus Write Control bus Read ALU PC: 1 0 0 I/O 17 I/O n I/O 16 I/O 18 Inst. Dec.

41. A B C D registers How computers work A [17] B  A A  [6] AA+B [7]A 31h C4h 26h 81h EAh 0h 5h 0 1 2 3 4 5 6 7 CPU 17 Logic circuit Address bus Data bus Write Control bus Read ALU PC: 9 1 I/O 17 I/O n I/O 16 I/O 18 Inst. Dec. 31

42. A B C D registers How computers work A [17] B  A A  [6] AA+B [7]A 31h C4h 26h 81h EAh 0h 5h 0 1 2 3 4 5 6 7 C4 26 5 CPU 17 Logic circuit 6 Address bus Data bus Write Control bus Read 9 9 ALU PC: 1 2 2 1 3 I/O 17 I/O n I/O 16 I/O 18 Inst. Dec.

43. A B C D registers How computers work A [17] B  A A  [6] AA+B [7]A 31h C4h 26h 81h EAh 0h 5h 0 1 2 3 4 5 6 7 81 EA CPU 7 Logic circuit Address bus Eh Data bus Write Control bus Read E 5 5 ALU + E 9 9 PC: 4 4 3 3 5 I/O 17 I/O n I/O 16 I/O 18 Inst. Dec.

44. Review Questions 1

45. Review Questions 2

46. Review Questions 2 (Cont’d)

47. Selecting a Microprocessor • Choose the right one for your application • Primary criteria: Cost, Power, Size, Speed • Others: package options, integrated peripherals, potential for future growth • Choose one with good software development support • development environment - good compiler and debugger availability • evaluation boards • in-circuit emulators for those with deep pockets • Operating system availability • Other considerations • Code density: affects power consumption, performance and system cost • Hardware availability: make sure you can actually purchase the microcontroller before designing it in • Prior expertise, licensing, etc

48. Summary • Microprocessors and embedded controllers are a ubiquitous part of life today • Concept of a microprocessor & microcontroller • Understand how a µP works • Headhunters report that EEs familiar with µC, µP design are in the highest possible demand • Web Resources: • How Microprocessors Work: • http://computer.howstuffworks.com/microprocessor.htm • http://www.intel.com/education/mpworks/ • http://www.cse.psu.edu/~cg471/03f/hw/pj5/how-micro.html • Great Microprocessors of the Past and Present: • http://www.sasktelwebsite.net/jbayko/cpu.html • Great Moments in Microprocessor History: • http://www-128.ibm.com/developerworks/library/pa-microhist.html