2. Microprocessor System Design3-1 ECE 424 Design of Microprocessor-Based Systems Dr. Esam Al_Qaralleh CE Department Princess Sumaya University for Technology Intel 8088 (8086) Microprocessor Structure

3. Microprocessor System Design3-2 Overview  Textbook: J. L. Antonakos, "An Introduction to the Intel Family of Microprocessors," Third Edition, Prentice Hall, 1999  Objectives: The course will provide knowledge to build and program microprocessor-based systems.  Microprocessor architecture  Architecture of microprocessor-based systems  Programming microprocessor-based systems  Future trends  Grading: Two midterms, one final exam, and homeworks

4. Microprocessor System Design3-3 What are microprocessor-based systems?  Microprocessor-based systems are electrical systems consisting of microprocessors, memories, I/O units, and other peripherals. Memory Output units Input units Bus Microprocessor Control unit Datapath ALU Reg.  Microprocessors access memories and other units through buses  The operations of microprocessors are controlled by instructions stored in memories  Microprocessors are the brains of the systems

5. Microprocessor System Design3-4 What are microprocessors?  A microprocessor is a processor (or Central Processing Unit, CPU) fabricated on a single integrated circuit. X Y Control unit IR PC ALU ACC MAR Data bus Control bus Address bus A simple microprocessor architecture

6. Microprocessor System Design3-5 Evolution of Computers  First generation (1939-1954) - vacuum tube  Second generation (1954-1959) - transistor  Third generation (1959-1971) - IC  Fourth generation (1971-present) - microprocessor

7. Microprocessor System Design3-6 Evolution of Computers Http://history.acusd.edu/gen/recording/computer1.html http://www.cs.virginia.edu/brochure/museum.html http://www.columbia.edu/acis/history/650.html  First generation (1939-1954) - vacuum tube IBM 650, 1954

8. Microprocessor System Design3-7 Evolution of Computers  Second generation (1954-1959) - transistor Http://history.acusd.edu/gen/recording/computer1.html http://www.computer50.org/kgill/transistor/trans.html Manchester University Experimental Transistor Computer

9. Microprocessor System Design3-8 Evolution of Computers  Third generation (1959-1971) - IC Http://history.acusd.edu/gen/recording/computer1.html http://www.piercefuller.com/collect/pdp8.html PDP-8, Digital Equipment Corporation  Thanks to the use of ICs, the DEC PDP-8 is the least expensive general purpose small computer in 1960s

10. Microprocessor System Design3-9 Evolution of Computers  Fourth generation (1971-present) - microprocessor  In 1971, Intel developed 4-bit 4004 chip for calculator applications. ALU Instruction decoder Reg. Program counter I/O Refresh logic System bus Control logic ROM/RAM bufferTimingReset http://www.intel.com A good review article: The History of The Microprocessor, Bell Labs Technical Journal, Autumn, 1997 Block diagram of Intel 40044004 chip layout

11. Microprocessor System Design3-10 Evolution of Intel Microprocessors 8080 8088 80286 80386 80486 Pentium P II P III P 4 8080 8088 80286 80386 80486 Pentium P IIP III P 4 8080 8088 80286 80386 80486 Pentium P II P III P 4 8080 8088 80286 80386 80486 Pentium P II P III P 4 Number of transistors Minimum transistor sizes (µm) Clock frequencies (MHz)MIPS

12. Microprocessor System Design3-11 Other Commercial Microprocessors  PowerPC ( IBM, Motorola )  Athlon, Dulon, Hammer ( AMD )  Crusoe ( Transmeta )  SPARC, UltraSPARC ( Sun Microsystems )  ARM cores ( Advanced RISC Machines )  MIPS cores ( MIPS Technologies )  TI’s TMS DSP chips ( Texas Instruments )  StarCore ( Motorola, Agere )       

13. Microprocessor System Design3-12 Applications of Microprocessor-Based Systems  Computers Block diagram of a computer Memory Timing & control Keyboard Interrupt control... Monitor Micro- processor Disk Other peripherals Bus  System performance is normally the most important design concern

14. 1.3 System block diagram System bus (data, address & control signals) Memory Interrupt circuitry Serial I/O Parallel I/O TimingCPU  P + associated logic circuitry: Bus controller Bus drivers Coprocessor ROM (Read Only Memory) (start-up program) RAM (Random Access Memory) DRAM (Dynamic RAM) - high capacity, refresh needed SRAM (Static RAM) - low power, fast, easy to interface Crystal oscillator Timing circuitry (counters dividing to lower frequencies) At external unexpected events,  P has to interrupt the main program execution, service the interrupt request (obviously a short subroutine) and retake the main program from the point where it was interrupt. Simple (only two wires + ground) but slow. Printer (low resolution) Modem Operator’s console Mainframe Personal computer Many wires, fast. Printer (high resolution) External memory Floppy Disk Hard Disk Compact Disk Other high speed devices

15. The Personal Computer Processor (8086 trough Pentium System bus (data, address & control signals) System ROM Interrupt logic (8259) Keyboard logic (8253) DMA Controller (8237) Timer logic (8253) Coprocessor (8087 trough 80387 640KB DRAM Expansion logic Keyboard Speaker Extension slots Video card Disk controller Serial port...

16. Microprocessor System Design3-15 CPU RAMROM Timer Interrupt I/O port USART A/D, D/A OSC. Applications of Microprocessor-Based Systems  Microcontrollers Block diagram of a microcontroller  In general, microcontrollers are cheap and have low performance  A microcontroller is a simple computer implemented in a single VLSI chip.  Microcontrollers are widely used in industrial control, automobile and home applications

17. Microprocessor System Design3-16 http://www.ti.com Applications of Microprocessor-Based Systems  ASICs  Microprocessors are embedded into ASIC chips to implement complex functions  In general, it requires that the microprocessors have low power consumption and take small silicon area A TI baseband chip for cellular phone applications

18. Microprocessor System Design3-17 Class Objectives  Hardware architecture of microprocessor-based systems  Programming of microprocessor-based systems  Microprocessor architecture  Memory organization  I/O units of microprocessor-based systems  How to put them together  Intel 80x86 instruction set  Microprocessor Interrupt services  Assembly language programming

19. Microprocessor System Design3-18 Overview & Review

20. Microprocessor System Design3-19 Overview  Intel 8088 facts 8088 VDD (5V) GND CLK 20-bit address 8-bit data   control signals To 8088 control signals from 8088 8088 signal classification  20 bit address bus allow accessing 1 M memory locations  16-bit internal data bus and 8-bit external data bus. Thus, it need two read (or write) operations to read (or write) a 16-bit datum  Byte addressable and byte-swapping Memory locations 5A 2F18000 18001 Low byte of word High byte of word Word: 5A2F

21. Microprocessor System Design3-20 Organization of 8088 AHAL BHBL CHCL DHDL SP BP SI DI ALU Flag register Execution Unit (EU) EU control  CS DS SS ESALU Data bus (16 bits) Address bus (20 bits) Instruction Queue Bus control External bus IP Data bus (16 bits) Bus Interface Unit (BIU) General purpose register Segment register

22. Microprocessor System Design3-21 General Purpose Registers 15870 AX BX CX DX AHAL BHBL CHCL DHDL Accumulator Base Counter Data SP BP SI DI Data Group Pointer and Index Group Stack Pointer Base Pointer Source Index Destination Index

23. Microprocessor System Design3-22 Arithmetic Logic Unit (ALU) n bits AB Y F Carry Y= 0 ? A > B ? F Y 0 0 0 A + B 0 0 1A - B 0 1 0A - 1 0 1 1A and B 1 0 0A or B 1 0 1 not A     Signal F control which function will be conducted by ALU.  Signal F is generated according to the current instruction.  Basic arithmetic operations: addition, subtraction,   Basic logic operations: and, or, xor, shifting, 

24. Microprocessor System Design3-23 Flag Register  OFDFIFTFZFSF  AFPFCF  015  Control Flags  Status Flags IF:Interrupt enable flag DF:Direction flag TF:Trap flag CF:Carry flag PF:Parity flag AF:Auxiliary carry flag ZF:Zero flag SF:Sign flag OF:Overflow flag  Flag register contains information reflecting the current status of a microprocessor. It also contains information which controls the operation of the microprocessor. 

25. Microprocessor System Design3-24 Instruction Machine Codes  Instruction machine codes are binary numbers  For Example: 1 0 0 0 1 0 0 0 1 1 0 0 0 0 1 1 MOV AL, BL MOV  Machine code structure OpcodeOperand1  Opcode tells what operation is to be performed. (EU control logic generates ALU control signals according to Opcode)  Some instructions do not have operands, or have only one operand  Operands tell what data should be used in the operation. Operands can be addresses telling where to get data (or where to store results) Register mode ModeOperand2  Mode indicates the type of a instruction: Register type, or Memory type

26. Microprocessor System Design3-25 EU Operation ALU Data bus (16 bits) AHAL BHBL CHCL DHDL SP BP SI DI General purpose register ALU Flag register EU control instruction 1011000101001010 1. Fetch an instruction from instruction queue 2. According to the instruction, EU control logic generates control signals. ( This process is also referred to as instruction decoding) 3. Depending on the control signal, EU performs one of the following operations:  An arithmetic operation  A logic operation  Storing a datum into a register  Moving a datum from a register  Changing flag register

27. Microprocessor System Design3-26 Generating Memory Addresses  How can a 16-bit microprocessor generate 20-bit memory addresses? Segment (64K) 0000 + 16-bit register 20-bit memory address 00000 FFFFF Left shift 4 bits Intel 80x86 memory address generation 1M memory space Offset Segment address Offset Addr1 Addr1 + 0FFFF

28. Microprocessor System Design3-27 Memory Segmentation  A segment is a 64KB block of memory starting from any 16-byte boundary  For example: 00000, 00010, 00020, 20000, 8CE90, and E0840 are all valid segment addresses  The requirement of starting from 16-byte boundary is due to the 4-bit left shifting  Segment registers in BIU CS SS DS ES Code Segment Data Segment Stack Segment Extra Segment 015

29. Microprocessor System Design3-28 Memory Address Calculation  Segment addresses must be stored in segment registers  Offset is derived from the combination of pointer registers, the Instruction Pointer (IP), and immediate values 0000 + Segment address Offset Memory address  Examples 348A0 4214 8AB43 CS IP+ Instruction address 50000 FFE0 FFE05 SS SP+ Stack address 12340 0022 23621 DS DI+ Data address

30. Microprocessor System Design3-29 Fetching Instructions  Where to fetch the next instruction? CS IP 1 2 3 4 0 0 1 2 1 2 3 5 2 MOV AL, 0 8088Memory  Update IP — After an instruction is fetched, Register IP is updated as follows: IP = IP + Length of the fetched instruction — For Example: the length of MOV AL, 0 is 2 bytes. After fetching this instruction, the IP is updated to 0014

31. Microprocessor System Design3-30 Accessing Data Memory  There is a number of methods to generate the memory address when accessing data memory. These methods are referred to as Addressing Modes  Examples: — Direct addressing: MOV AL, [0300H] 12340 0300 26401 DS Memory address (assume DS=1234H) — Register indirect addressing: MOV AL, [SI] 12340 0310 26501 DS Memory address (assume DS=1234H) (assume SI=0310H)

32. Microprocessor System Design3-31 Reserved Memory Locations FFFFF FFFF0 003FF 00000 Reset instruction area Interrupt pointer table  Locations from 00000H to 003FFH are used for the interrupt pointer table  Locations from FFFF0H to FFFFFH are used for system reset code  Some memory locations are reserved for special purposes. Programs should not be loaded in these areas  It has 256 table entries  Each table entry is 4 bytes 256  4 = 1024 = memory addressing space From 00000H to 003FFH

33. Microprocessor System Design3-32 Interrupts  An interrupt is an event that occurs while the processor is executing a program  The interrupt temporarily suspends execution of the program and switch the processor to executing a special routine (interrupt service routine)  When the execution of interrupt service routine is complete, the processor resumes the execution of the original program Hardware InterruptsSoftware Interrupts  Caused by activating the processor’s interrupt control signals (NMI, INTR)  Caused by the execution of an INT instruction  Caused by an event which is generated by the execution of a program, such as division by zero  Interrupt classification  8088 can have 256 interrupts

34. Microprocessor System Design3-33 Minimum and Maximum Operation modes  Intel 8088 (8086) has two operation modes: Minimum Mode Maximum Mode  8088 generates control signals for memory and I/O operations  It needs 8288 bus controller to generate control signals for memory and I/O operations  Some functions are not available in minimum mode  It allows the use of 8087 coprocessor; it also provides other functions  Compatible with 8085-based systems