EC 8691 Microprocessor and Microcontroller.pptx

Microprocessor and Microcontroller

1. EC 8691 Microprocessor and Microcontroller A.Gobinath Assistant Professor/IT Velammal College of Engineering and Technology

2. Course Outline UNIT I - THE 8086 MICROPROCESSOR (9) Introduction to 8086 – Microprocessor architecture – Addressing modes - Instruction set and assembler directives – Assembly language programming – Modular Programming - Linking and Relocation - Stacks - Procedures – Macros – Interrupts and interrupt service routines – Byte and String Manipulation. UNIT II - 8086 SYSTEM BUS STRUCTURE (9) 8086 signals – Basic configurations – System bus timing –System design using 8086 – IO programming – Introduction to Multiprogramming – System Bus Structure - Multiprocessor configurations – Coprocessor, Closely coupled and loosely Coupled configurations – Introduction to advanced processors.

3. UNIT III - I/O INTERFACING (9) Memory Interfacing and I/O interfacing - Parallel communication interface – Serial communication interface – D/A and A/D Interface - Timer – Keyboard /display controller – Interrupt controller – DMA controller – Programming and applications Case studies: Traffic Light control, LED display , LCD display, Keyboard display interface and Alarm Controller. UNIT IV - MICROCONTROLLER (9) Architecture of 8051 – Special Function Registers(SFRs) - I/O Pins Ports and Circuits - Instruction set - Addressing modes - Assembly language programming.   UNIT V - INTERFACING MICROCONTROLLER (9) Programming 8051 Timers - Serial Port Programming - Interrupts Programming – LCD & Keyboard Interfacing - ADC, DAC & Sensor Interfacing - External Memory Interface- Stepper Motor and Waveform generation.

4. Unit 1 - The 8086 Microprocessor Introduction Mp is a brain of Microcomputer It is a single chip which is capable of processing data It Control all components in computer It executes sequence of instruction Program controlled semiconductor device (IC) which fetches (from memory), decodes and executes instructions.

5. used to write a program for a microcomputer Machine Language Binary form of program (Instructions / data in1’ and 0’s form) Difficult for programmer to memorize Error occurs easily Assembly Language More readable form of machine language Uses mnemonic codes Assembler needed to translate to machine code High Level Language Uses English-like program statements Programs can usually be written faster & easily Compiler needed to translate high-level language statement to machine code Executed slowly ; Require more memory Three Levels of Programming

6. Evaluation of Microprocessor First Generation Between 1971 – 1973 PMOS technology, non compatible with TTL 4 bit processors  16 pins 8 and 16 bit processors  40 pins Due to limitations of pins, signals are multiplexed Second Generation During 1973 NMOS technology  Faster speed, Higher density, Compatible with TTL 4 / 8/ 16 bit processors  40 pins Ability to address large memory spaces and I/O ports Greater number of levels of subroutine nesting Better interrupt handling capabilities Intel 8085 (8 bit processor) Third Generation During 1978 HMOS technology  Faster speed, Higher packing density 16 bit processors  40/ 48/ 64 pins Easier to program Dynamically relatable programs Processor has multiply/ divide arithmetic hardware More powerful interrupt handling capabilities Flexible I/O port addressing Intel 8086 (16 bit processor) Fourth Generation During 1980s Low power version of HMOS technology (HCMOS) 32 bit processors Physical memory space 2 24 bytes = 16 Mb Virtual memory space 2 40 bytes = 1 Tb Floating point hardware Supports increased number of addressing modes Intel 80386

7. Microprocessor is scaling from 4004 to Pentium 4 Microprocessor is identified with Word size of data

8. Functional blocks Flag Register Timing and control unit Register array or internal memory Instruction decoding unit PC/ IP ALU Control Bus Address Bus Data Bus

9. Operation of Microprocessor 1. Fetch 2. Decode 3. Execute

10. 8086 Microprocessor It is enhanced version of 8085 MP designed by Intel in 1976 Powerful instruction set Its 16 bit MP, its send 16 bit data at a time Operation Modes: Maximum mode Minimum mode

11. 8086 is a 40 bin IC Its operation volts is 5 volt Operating frequency is 5MHz Total memory addressing capacity is 1MB 16 bit data bus and 20 bit address bus It has 14 – 16bit resisters Higher throughput Approximately 29, 000 transistors, 40 pin DIP, 5V supply 20-bit address to access memory  can address up to 220 = 1 megabytes of memory space

12. Pins and Signals of 8086 AD -AD 15 (Bidirectional) Address/Data bus Low order address bus; these are multiplexed with data. When AD lines are used to transmit memory address the symbol A is used instead of AD, for example A -A 15 . When data are transmitted over AD lines the symbol D is used in place of AD, for example D -D 7 , D 8 -D 15 or D -D 15 . A 16 /S 3 , A 17 /S 4 , A 18 /S 5 , A 19 /S 6 High order address bus. These are multiplexed with status signals

13. BHE (Active Low)/S 7 (Output) Bus High Enable/Status It is used to enable data onto the most significant half of data bus, D 8 -D 15 . 8-bit device connected to upper half of the data bus use BHE (Active Low) signal. It is multiplexed with status signal S 7 . MN/ MX MINIMUM / MAXIMUM This pin signal indicates what mode the processor is to operate in. RD (Read) (Active Low) The signal is used for read operation. It is an output signal. It is active when low.

14. READY This is the acknowledgement from the slow device or memory that they have completed the data transfer. The signal made available by the devices is synchronized by the 8284A clock generator to provide ready input to the 8086. The signal is active high.

15. Architecture of 8086 Microprocessor

16. Execution Unit (EU ) EU executes instructions that have already been fetched by the BIU. BIU and EU functions separately. Bus Interface Unit (BIU) BIU fetches instructions, reads data from memory and I/O ports, writes data to memory and I/ O ports .

17. Bus Interface Unit (BIU) The Bus Interface Unit (BIU) manages the data, address and control buses. The BIU functions in such a way that it: Fetches the sequenced instruction from the memory, Finds the physical address of that location in the memory where the instruction is stored and Manages the 6-byte pre-fetch queue where the pipelined instructions are stored.

18. Instruction Pointer (IP) The IP register is a 16-bit register which contains the address of the next instruction to be executed. Instruction pointer values get incremented automatically after every instruction is executed. In 80386 and the latest versions, the size of this register is extended to 32-bits and is known as the EIP register. You cannot change the content of this register or access it directly.  Only instructions like branching, jump, loops, interrupts or stacks-related instructions can change the IP.

19. Segment Registers

20. Prefetch Queue ( Pipelining) 8086 microprocessor implements basic pipelining with the help of 6 bytes prefetch queue. This is a first-in-first-out queue. It fetches the next instruction from the code segment at the same time the execution unit executes the current instruction. The fetching and executing stage works in parrel . Hence, 8086 supports 2 steps pipelining.

21. Execution Unit (EU) The Execution Unit (EU) performs the decoding and execution of the instructions that are being fetched from the desired memory location. Arithmetic and Logic Unit ( ALU) 16-bit General Purpose Registers 16-bit Special Purpose Registers Instruction Register Instruction Decoder Circuit Flag/Status Register

22. General Purpose Registers

23. Flag Register

24. Addressing Modes

25. Various methods used to access instruction operands is called as Addressing Mode General Instruction Format Operands may be contained in Registers, Memory I/O ports. Three basic modes of addressing are Immediate Register Memory Addressing Modes OPCODE Operand       Operand

26. Memory Segmentation The memory in an 8086 based system is organized as segmented memory The CPU 8086 is able to access 1MB of physical memory. The complete 1MB of memory can be divided into 16segments, each of 64KB size and is addressed by one of the segment register. The 16-bit contents of the segment register actually point to the starting location of a particular segment. The address of the segments may be assigned as 0000H to F000h respectively To address a specific memory location within a segment, we need an offset address. The offset address values are from 0000H to FFFFH so that the physical addresses range from 00000H to FFFFFH

27. 1MB Memory Space divided into non-overlapping segments             Seg-1 Seg-2 Seg-3 Seg-4 Seg-5 Seg-6 Seg-7 Seg-8 Seg-15 Seg-16 64 KB 00000 0FFFF 10000 1FFFF 20000 2FFFF EFFFF FFFFF

28. The BIU has a dedicated adder for determining Physical memory addresses Physical Memory Address Generation Physical Address (20 Bits) Adder Offset Value or Effective address (16 bits) Segment Register (16 bits) 0 0 0 0

29. Even though addresses associated with the instructions are 16 bits only, allows the memory capacity to be 1MB More than one Code, Data or Stack segment can be used for programs more than 64KB long. Facilitates, use of separate memory areas for a program, its data and the stack. Permit a program and/or its data to be put into different areas of memory each time the program is executed. Advantages of using Segment Registers

30. Assembly Language Programming High Level language Assembly Programming Assembler [1200] -> Address 1200 -> Register

31. Modular Programming Reasons for breaking a program into small parts: Modules are easy to comprehend Different modules can be assigned to different programmers Debugging and testing done in orderly fashion Documentation – easily understood Modifications – localized Frequently used tasks can be programmed into modules that are stored in libraries and used by several programs

32. Assembler does the following in steps: Decides the address of each label Substitutes the values for each of the constants and variables Forms the machine code for mnemonics and data in the assembly language program Assembler A Program that c onverts assembly language program into equivalent machine codes, which may further be converted to executable codes During the above process, assembler finds out syntax errors, but logical errors are not found

33. For completing these tasks assembler needs hints from the programmer ; like - Storage required for a particular constant or a variable, Logical names of the segment Types of the different routines and modules, End of files, etc.

34. An assembler translates the assembly language program into machine language program Assembly language program à source codes Machine language program à object codes Assembler converts Source code into Object code Linker converts Object code into executable code

35. Assembler works in passes: In the first pass, it determines the displacement of the named data items, the offset of labels etc. and puts this information to in a symbol table. In the second pass, it produces the binary codes for each instructions and inserts the offsets etc. that it calculated in the first pass. It generates two files namely object file (.OBJ) and assembler list file (.LST).

36. Linker is a program used to join several object files into one large object file. While writing large programs it is good to divide them into modules so that each modules can be written, tested, debugged independently and then use linker to combine the modules to form the actual program. It produces two files - link file which contains the binary codes of all the combined modules and a link map file which contains the address information about the linked files. Linker

37. Locator A locator is the program used to assign the specific addresses of where the segments of object code are to be loaded in to main memory. Examples include EXE2BIN which comes with the IBM PC DOS. Converts .exe to .bin files which has physical addresses

38. Debugger A debugger is the program which allows to load the object code program in to system memory. It allows to look at the contents of the registers and memory locations after a program is run. It also allows to set breakpoints at any points in the program. It allows to find the source of the problem into the program. There are lots of debuggers available like Borland Turbo Debugger, Microsoft’s Code view debugger etc.

39. A stack is a Last-Input-First-Output (LIFO) read/write memory ( i.e ) data segment It is a top-down data structure , whose elements are accessed using SS and SP registers Stack pointer is decremented by 2 while ‘ pushing into’ the stack Stack pointer is incremented by 2 while ‘ poping off’ the stack Stack Stack is used to: Store return addresses whenever a procedure is called Save contents of registers / register status of the processor while calling a procedure Hold data or addresses that will be acted upon by the procedure

40. A procedure is a sequence of instructions written to perform a particular task Replacing a set of frequently used instructions by a procedure saves program memory space A CALL instruction in the main program causes 8086 to the execute the set of instructions contained in a procedure A RET instruction at the end of procedure returns execution to the next instruction in the main program Procedures

41. A macro is the repeatedly appearing group of instructions, that is given a name at the start of the program. A macro can be defined anywhere in a program using the directives MACRO and ENDM Defining a Macro: name MACRO [optional arguments] statements.. statements.. ENDM Macro

42. Capability to suspend the execution of running program and execution of another program to fulfill specific requirement upon request After finishing the second program, automatically return to the first program and start execution from where it was left What is an interrupt?

43. Sources of 8086 interrupts 8086 interrupts can be classified into two types: 1) Predefined interrupt Some error condition produced by execution of an instruction, e.g., trying to divide some number by zero. ( Interrupt due to exceptions ) 2) User defined interrupt i ) Hardware interrupt An external signal applied to NMI , INTR pins ii) Software interrupt Execution of interrupt instruction INT

44. NMI (Non Maskable Interrupt): Any interrupt request at NMI input pin cannot be masked or disabled by any means; type is implicit INTR: This hardware interrupt can be masked using Interrupt Flag (IF); 256 Types (00h to FFh ); to handle more than one interrupts that occur at a time, Programmable Interrupt Controller is required. INT: This is a software interrupt; the type is specified in the instruction At the end of each instruction cycle, 8086 checks if any interrupt service has been requested. If yes, then 8086 responds to the interrupt by stepping through the following series of actions:

45. String A string is a series of bytes or words stored in successive memory locations 8086 can perform the following operations on strings Moving a string from one place in memory to another Compare two strings Search a string for a specified character

46. Thank You

47. Unit II