Microprocessor System Design Omid Fatemi 8088 Microprocessor (omid@fatemi.net)

Outline Moore’s law 80x86 history Pin configuration Minimal / Maximal mode Address latch enable Bi-directional data bus

Computer modules Address Bus Keyboard Monitor Printer Mouse Microphone Disk CPU Memory (RAM, ROM) Peripherals (IO) Talk about the effects of the size of data bus - bidirectional Size of address bus – number of locations and byte addressable - unidirectional Data Bus Control Bus

Intel’s Microprocessors and Moore’s law Model Year Introduced Clock Rate Transistors per chip   4004 1971 0.1 MHz 2,250 8008 1972 . 0.2 MHz 3,500 8080 1974 . 2 MHz 5,000 8086 1978 * 5 MHz 29,000 80286 1982 * 6 MHz 120,000 386™ processor 1985 ** 16 MHz 275,000 486™ DX processor 1989 ** 26 MHz 1,180,000 Pentium® processor 1993 *** 60 MHz 3,100,000 Pentium II processor 1997 *** 233 MHz 7,500,000 Pentium III processor 1999 *** 450 MHz 24,000,000 Pentium 4 processor http://www.intel.com/pressroom/archive/backgrnd/30thann_funfacts.htm 2000 *** 1500 MHz 42,000,000 Moore’s law in 1965 (transistors per integrated circuit would double every 18 months ) . = 8 bit bus; * = 16 bit bus; ** = 32 bit bus; *** = 32/64 bit bus 4004 was the 1st microprocessor; it had only a 4 bit bus. 8088 (the 8-bit sister of the 8086) at 5 Mhz powered the first IBM PCs.

From Intel Site Today, there are 40 microprocessors in the average middle-class American household. The number increases to 50 when a PC and all the surrounding paraphernalia are added.1 These microprocessors are hidden in bathroom scales with digital readouts, irons with automatic shutdown switches and even the common electronic toothbrush that possesses some 3,000 lines of computer code.1 Today's automobiles have, on average, more than 50 microprocessors controlling things such as air bags, brakes, engines, windows, door locks and cruise control.2 Developed during the 1970s, the microprocessor became most visible as the central processor of the personal computer. Microprocessors also play supporting roles within larger computers as smart controllers for graphics displays, storage devices, and high-speed printers. However, the vast majority of microprocessors are used to control a broad array of devices from consumer appliances and PC-enhanced toys to satellites orbiting the earth.3 The microprocessor has made possible the inexpensive hand-held electronic calculator, the digital wristwatch, and the electronic game. Microprocessors are used to control consumer electronic devices, such as the programmable microwave oven and videocassette recorder; to regulate gasoline consumption and antilock brakes in automobiles; and to monitor alarm systems.3 http://www.intel.com/pressroom/archive/backgrnd/30thann_funfacts.htm It all started 30 years ago, November 1971 Intel began development of the first microprocessor in 1969 as part of a project to design a set of chips for a family of programmable calculators from Japanese calculator manufacturer Busicom. Originally, Busicom owned the rights to the microprocessor having paid Intel $60,000. Realizing the potential for the "brain" chip, Intel offered to return the $60,000 in exchange for the rights to the microprocessor design. Busicom agreed and Intel introduced the 4004 to the worldwide market on November 15, 1971. The 4004 sold for $200 each. The key to the success of the microprocessor idea was to provide a software programmable device. Prior to the invention of the programmable microprocessor, chips were designed to perform specific "fixed" functions. Today's state-of-the-art Pentium® 4 Processor The latest direct descendant of the 4004 is the Intel® Pentium® 4 processor for desktop personal computers. Today's cutting edge Pentium 4 microprocessor operates at 2 billion cycles per second. It took 28 years to go from a speed of 108,000 cycles per second performance in the 4004 brain chip to1 billion cycles per second (1 gigahertz) with the Intel® Pentium® III processor - and only 18 months to break the 2 gigahertz barrier with the August announcement of the latest Pentium 4 microprocessor. Pentium 4 processor-based personal computers (at price points ranging from under $1,000 to $2,000) are fueling the latest trends in home computing - from digital music and home digital movie making to photo-realistic 3D images and visual environments delivered on and off the net in advanced games, education and shopping experiences.

The Microprocessor An integrated circuit with millions of transistors interconnected with very small aluminum wires. Controls and directs activities of the PC Execute stored programs

Von Neumann Architecture Microprocessor Memory Address Lines Actual Processor Program Data Lines Registers Data Control Lines

The 8086 Family:The Late 1970’s Could address up to 1 mb of memory at a time when other CPU’s could only address 64 kb. The 16 bit external bus too powerful. The 8088 replaced the 8086 and had only an 8 bit external bus The 8088 CPU was the first chip used in IBM’s microcomputers

The 80286 Family:1983 Wanted to make the 286 backward compatible with the 8088’s. So had 2 modes: Real mode-less powerful Protected mode-very powerful Could access up to 16 mb of memory Needed a special operating system But most users only had DOS

The 386 DX: 1985 First true 32 bit chip, all buses 32 bits wide Capable of running in real mode, 286 protected mode and its own 386 protected mode In 386 protected mode it had 2 new functions: Virtual memory- could use hard drive to pretend that computer had up to 4 GB of data! Virtual 8086- 8086 bubbles created for DOS

The 386 SX:1988 How different from the 386DX? External data bus reduced to 16 bits Address bus reduced to 24 bits, which limited memory use to 16 mb First popular lap tops were based on the 386SX but was called the 386 SL and ran on 3.3 volts

The 486DX:1989 How different from the 386 family? A built in math coprocessor Performs high math functions A built in 8K cache on same chip This was an SRAM cache that stores code read in the past. When the CPU asks for the code again, it doesn’t have to go to DRAM to get it.

486SX:1991 Same as 486 DX except the math co-processor is disabled.

The Pentiums:1993 Had 64 bit external data bus that split internally as 2 dual pipelined 32 bit buses Supported an 8K write through cache for programs Most early pentiums ran at 3.3 volts. This conserved heat. Voltage regulators on the motherboard can decrease voltage

Pentiums continued Includes clock doubling through the setting of jumpers Most later Pentuims use SPGA, Standard Pin Grid Array. This allows staggers the pens and allows for higher pen density

Pentium Pro(P6):1995 Quad pipelining Dynamic processing On chip L2 cache Uses Socket 8

Recent Pentiums:After 1996 MMX- helps with multimedia products Increased multipliers/clocks- 45 multipliers Improved processing- better cache branch predicting Improved superscalar architecture SSE/SSE2 instructions

8088 Microprocessor Minimum Mode

Pin Configuration

Power and Ground Pins Vcc – pin 40 Gnd – pin 1 and 20

Address Pins AD0..AD7 A8..A15 A19/S6, A18/S5, A17/S4, A16/S3

Data Pins AD0..AD7

Control Pins MN/MX’ (input) READY (input) CLK (input) RESET (input) Indicates what mode the processor is to operate in READY (input) When given an input LOW, it will go into a wait state CLK (input) Provides basic timing for the processor RESET (input) Causes the processor to immediately terminate its present activity To reset the microprocessor, this must be HIGH for at least 4 clock cycles

Control Pins TEST’ (input) HOLD (input) HLDA (output) Connect this to HIGH HOLD (input) Connect this to LOW HLDA (output)

Control Pins INTR (input) INTA’ (output) NMI (input) Interrupt request Interrupt Acknowledge NMI (input) Non-maskable interrupt

Control Pins DEN’ (output) DT/R’ (output) IO/M’ (output) Data Enable It is LOW when processor wants to receive data or processor is giving out data DT/R’ (output) Data Transmit/Receive When HIGH, direction of data lines is from microprocessor to memory/devices When LOW, direction of data lines is from memory/devices to microprocessor IO/M’ (output) Device/Memory When HIGH, microprocessor wants to access I/O Device When LOW, microprocessor wants to access memory

Control Pins RD’ (output) WR (output) ALE (output) When LOW, it indicates that the microprocessor is performing a read access WR (output) When LOW, it indicates that the microprocessor is performing a write access ALE (output) Address Latch Enable Provided by the microprocessor to latch address When this is HIGH, microprocessor is using AD0..AD7, A19/S6, A18/S5, A17/S4, A16/S3 as address lines

Clock Signal needed by the microprocessor to synchronize signals ideally a square wave having a constant frequency

8086 Signals

Providing Clock, Reset, and Ready Signal

Minimum Mode

Minimum Mode

Minimum Mode

MEMORY 8088 Minimum Mode D7 - D0 DEN DT / R AD7 - AD0 A7 - A0 A15 - A8 A19/S6 - A16/S3 ALE RD RD IO / M WR WR

Processor Timing Diagram of 8088 (Minimum Mode) for Memory or I/O Read CLOCK __ DT/R ALE AD7 - AD0 A7 - A0 D7 - D0 (from memory) A15 - A8 A15 - A8 A19/S6 - A16/S3 A19 - A16 S6 - S3 __ IO/M if I/O ACCESS this is HIGH, if MEMORY ACCESS this is LOW ____ RD ______ DEN

Will the circuit be able to perform memory read? ;assume that initially the values ;of the registers are: ;BX = 1234, DS = 9000 MOV AL, [BX]

Processor Timing Diagram of 8088 (Minimum Mode) for Memory or I/O Read CLOCK __ DT/R ALE AD7 - AD0 A7 - A0 D7 - D0 (from memory) A15 - A8 A15 - A8 A19/S6 - A16/S3 A19 - A16 S6 - S3 __ IO/M if I/O ACCESS this is HIGH, if MEMORY ACCESS this is LOW ____ RD ______ DEN

MEMORY 8088 Minimum Mode D7 - D0 DEN DT / R AD7 - AD0 A7 - A0 A15 - A8 A19/S6 - A16/S3 ALE RD RD IO / M WR WR

74LS373 MEMORY 8088 Minimum Mode D7 - D0 DEN DT / R D7 - D0 Q7 - Q0 OE LE 74LS373 D7 - D4 Q7 - Q4 D3 - D0 Q3 - Q0 GND AD7 - AD0 A7 - A0 A15 - A8 A19 - A16 A15 - A8 MEMORY 8088 A19/S6 - A16/S3 ALE RD RD IO / M WR WR

Octal Transparent Latch with 3-State Output

Processor Timing Diagram of 8088 (Minimum Mode) for Memory or I/O Read CLOCK __ DT/R ALE AD7 - AD0 A7 - A0 D7 - D0 (from memory) A15 - A8 A15 - A8 A19/S6 - A16/S3 A19 - A16 S6 - S3 A19 - A0 A19 - A0 from 74LS373 from 74LS373 to memory __ IO/M if I/O ACCESS this is HIGH, if MEMORY ACCESS this is LOW ____ RD ______ DEN

Will the circuit be able to perform memory read? ;assume that initially the values ;of the registers are: ;BX = 1234, DS = 9000 MOV AL, [BX]

Processor Timing Diagram of 8088 (Minimum Mode) for Memory or I/O Read (with 74373)

Minimum Mode What about Data read and write

74LS245 74LS373 MEMORY 8088 74LS373 74LS373 Minimum Mode A7 - A0 B7 - B0 E DIR 74LS245 D7 - D0 DEN DT / R AD7 - AD0 D7 - D0 Q7 - Q0 A7 - A0 A15 - A8 GND OE 74LS373 A19 - A16 LE A15 - A8 D7 - D0 Q7 - Q0 MEMORY 8088 GND OE 74LS373 LE A19/S6 - A16/ D7 - D4 Q7 - Q4 S3 D3 - D0 Q3 - Q0 GND OE 74LS373 ALE LE RD RD IO / M WR WR

Processor Timing Diagram of 8088 (Minimum Mode) for Memory or I/O Read (with 74245)

Minimum Mode

Minimum Mode

Minimum Mode

Minimum Mode