1. CNET 315 Microprocessors & Assembly Language
Phiros Mansur Nalakath
Course Coordinator
Jazan University
CNET 315 Microprocessor & Assembly Language

2. Chapter 1 COMPUTER NUMBER SYSTEMS & DIGITAL DEVICES
CNET 315 Microprocessor & Assembly Language

3. Objectives of Chapter-1
To understand the basic number systems used in Computers.
To Conversions between the major number systems
To understand fundamentals of devices like Latches, Flip Flops, Registers, RAM, ROM and ALU etc.
CNET 315 Microprocessor & Assembly Language

4. Number Systems Number System Base Symbols Used by humans?
Used in computers?
Decimal 10
0, 1, … 9
Yes No
Binary 2
0, 1
Hexa- decimal 16
0, 1, … 9,
A, B, … F
CNET 315 Microprocessor & Assembly Language

5. Quick Example
2510 = = 1916
Base
CNET 315 Microprocessor & Assembly Language

6. Weight 12510 => 5 x 100 = 5 2 x 101 = 20 1 x 102 = 100 125 Base
CNET 315 Microprocessor & Assembly Language

7. Quantities/Counting (1 of 3)
Decimal
Binary
Hexa- decimal 1 2 10 3 11 4
100 5
101 6
110 7
111
CNET 315 Microprocessor & Assembly Language

8. Quantities/Counting (2 of 3)
Decimal
Binary
Hexa- decimal 8
1000 9
1001 10
1010 A 11
1011 B 12
1100 C 13
1101 D 14
1110 E 15
1111 F
CNET 315 Microprocessor & Assembly Language

9. Quantities/Counting (3 of 3)
Decimal
Binary
Hexa- decimal 16
10000 10 17
10001 11 18
10010 12 19
10011 13 20
10100 14 21
10101 15 22
10110 23
10111
CNET 315 Microprocessor & Assembly Language

10. Binary Number System Binary Number System has base 2.
It uses the digits 0 and 1 only
Example :
CNET 315 Microprocessor & Assembly Language

11. Binary Addition

12. Addition - Example

13. Binary Subtraction Just like subtraction in any other base
Minuend
Subtrahend
Difference
And when a borrow is needed. Note that the borrow gives us 2 in the current bit position. .
9/15/09 - L15 Decoders, Multiplexers
Copyright Joanne DeGroat, ECE, OSU

14. Hexadecimal (Hex) Numbering System
Base: 16
Digits: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F
Hexadecimal number: 1F416
= (1 x 162 ) + (F x 161) + (4 x 160)

15. Hexadecimal (Hex) Extra Digits
Decimal Value Hexadecimal Digit 10 A 11 B 12 C 13 D 14 E 15 F

16. Hexadecimal Addition
CNET 315 Microprocessor & Assembly Language

17. Binary to Decimal Decimal Octal Binary Hexadecimal
CNET 315 Microprocessor & Assembly Language

18. Example
Bit “0”
=> 1 x 20 = x 21 = x 22 = x 23 = x 24 = x 25 = 32
4310
CNET 315 Microprocessor & Assembly Language

19. Hexadecimal to Decimal
Octal
Binary
Hexadecimal
CNET 315 Microprocessor & Assembly Language

20. Example
ABC16 => C x 160 = 12 x 1 = B x 161 = 11 x 16 = A x 162 = 10 x 256 = 2560
274810
CNET 315 Microprocessor & Assembly Language

21. Decimal to Binary Decimal Octal Binary Hexadecimal
CNET 315 Microprocessor & Assembly Language

22. Example
12510 = ?2
12510 =
CNET 315 Microprocessor & Assembly Language

23. Hexadecimal to Binary Decimal Octal Binary Hexadecimal
CNET 315 Microprocessor & Assembly Language

24. Example
10AF16 = ?2
A F
10AF16 =
CNET 315 Microprocessor & Assembly Language

25. Decimal to Hexadecimal
Octal
Binary
Hexadecimal
CNET 315 Microprocessor & Assembly Language

26. Example
= ?16
77 2 16
= D
0 4
= 4D216
CNET 315 Microprocessor & Assembly Language

27. Binary to Hexadecimal Decimal Octal Binary Hexadecimal
CNET 315 Microprocessor & Assembly Language

28. Example
= ?16
B B
= 2BB16
CNET 315 Microprocessor & Assembly Language

29. Exercise – Convert ... Decimal Binary Hexa- decimal 33 1110101 2BD
Don’t use a calculator!
CNET 315 Microprocessor & Assembly Language

30. Basic Digital Devices Latch Flip Flop Register RAM ROM ALU SRAM & DRAM
CNET 315 Microprocessor & Assembly Language

31. Latch
What is a Latch?
A  latch is a circuit that has two stable states and can be used to store state information. .
Example : RS-Latch
CNET 315 Microprocessor & Assembly Language

32. Latch
CNET 315 Microprocessor & Assembly Language

33. Flip Flop What is a Flip Flop?
flip-flop is a bistable multivibrator. The circuit can be made to change state by signals applied to one or more control inputs and will have one or two outputs
Example: D-Flip Flop
CNET 315 Microprocessor & Assembly Language

34. Register What is a Register?
A register may hold an instruction, a storage address, or any kind of data (such as a bit sequence or individual characters).
A processor register (CPU register) is one of a small set of data holding places that are part of the computer processor.
CNET 315 Microprocessor & Assembly Language

35. RAM Random Access Memory (RAM) SRAM DRAM Static RAM Dynamic RAM SDRAM
DDRAM
CNET 315 Microprocessor & Assembly Language

36. Static & Dynamic RAM
Static RAM (SRAM) and Dynamic RAM (DRAM) are two types of RAM.
They both are different in many contexts like speed, capacity.
DRAM makes use of single transistor and capacitor for each memory cell.
Memory cell of SRAM makes use of an array of 6 transistors.
DRAM needs refreshing, whereas SRAM does not require refreshing of the memory cell.
Both retain data till the time they are supplied with power.
CNET 315 Microprocessor & Assembly Language

37. ROM – Read Only Memory Different types of ROMs ROM : Read Only Memory
PROM : Programmable Read Only
Memory
EPROM : Erasable Programmable Read
Only Memory
EEPROM : Electrically Erasable
Programmable Read Only Memory
CNET 315 Microprocessor & Assembly Language

38. ALU Arithmetic and Logic Unit
ALU is the part of a computer processor (CPU) that carries out arithmetic and logic operations on the operands in computer instruction words.
ALU is divided into two units, an arithmetic unit (AU) and a logic unit (LU).
Some processors contain more than one AU
CNET 315 Microprocessor & Assembly Language

39. Reference Book 1. Douglas V. Hall, “Microprocessors and Interfacing ”
CNET 315 Microprocessor & Assembly Language