1. Microprocessor System Design
Omid Fatemi
8088 Microprocessor

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

3. 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

4. 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
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.

5. 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
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, 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.

6. 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

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

8. 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

9. The 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

10. 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 bubbles created for DOS

11. 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

12. 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.

13. 486SX:1991
Same as 486 DX except the math co-processor is disabled.

14. 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

15. 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

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

17. 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

18. 8088 Microprocessor
Minimum Mode

19. Pin Configuration

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

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

22. Data Pins
AD0..AD7

23. 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

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

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

26. 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

27. 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

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

29. 8086 Signals

30. Providing Clock, Reset, and Ready Signal

31. Minimum Mode

32. Minimum Mode

33. Minimum Mode

34. 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

35. 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

36. 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]

37. 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

38. 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

39. 74LS373 MEMORY 8088 Minimum Mode D7 - D0 DEN DT / R D7 - D0 Q7 - Q0 OELE
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

40. Octal Transparent Latch with 3-State Output

41. 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

42. 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]

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

44. Minimum Mode
What about Data read and write

45. 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

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

47. Minimum Mode

48. Minimum Mode

49. Minimum Mode

50. Minimum Mode