Lec-1-2-27102021-122208am.pptx for embedded design
- 2. Topic #1 Introduction to Computing 2
- 3. Course Title – Embedded Systems Design Topic# 1 INTRODUCTION TO COMPUTING 3 • Gates • Decision Making Operators • Number Representation • Adder/ Subtractor • Memorizing Elements • Towards a Processor • Inside the CPU Outline
- 4. Course Title – Embedded Systems Design Topic# 1 INTRODUCTION TO COMPUTING 4 • Gates • Decision Making Operators • Number Representation • Adder/Subtractor • Memorizing Elements • Towards a Processor • Inside the CPU Outline
- 5. Course Title – Embedded Systems Design Topic# 1 INTRODUCTION TO COMPUTING 5 Gates Logic Gates
- 6. Course Title – Embedded Systems Design Topic# 1 INTRODUCTION TO COMPUTING 6 Gates Logic Gates In electronics what is 1 and what is 0 ???? 3.3 V or (5 V) 1 GND 0 A B Q GND GND GND 3.3 V GND GND GND 3.3 V GND 3.3 V 3.3 V 3.3 V
- 7. Course Title – Embedded Systems Design Topic# 1 INTRODUCTION TO COMPUTING 7 • Gates • Decision Making Operators • Number Representation • Adder/Subtractor • Memorizing Elements • Towards a Processor • Inside the CPU Outline
- 8. Course Title – Embedded Systems Design Topic# 1 INTRODUCTION TO COMPUTING 8 s1 s0 y 0 0 a 0 1 b 1 0 c 1 1 d Multiplexer Decision/Selection Operators Decision Making Operators
- 9. Course Title – Embedded Systems Design Topic# 1 INTRODUCTION TO COMPUTING 9 a b w x y z 0 0 1 0 0 0 0 1 0 1 0 0 1 0 0 0 1 0 1 1 0 0 0 1 a b c d w x 1 0 0 0 0 0 0 1 0 0 0 1 0 0 1 0 1 0 0 0 0 1 1 1 Encoder a b c d w x 1 x x x 0 0 0 1 x x 0 1 0 0 1 x 1 0 0 0 0 1 1 1 Priority Encoder Decision/Selection Operators Decision Making Operators
- 10. Course Title – Embedded Systems Design Topic# 1 INTRODUCTION TO COMPUTING 10 • Gates • Decision Making Operators • Number Representation • Adder/Subtractor • Memorizing Elements • Towards a Processor • Inside the CPU Outline
- 11. Course Title – Embedded Systems Design Topic# 1 INTRODUCTION TO COMPUTING 11 Number Representation Unsigned Number Representation General Rule for Unsigned Representation of a system having x as base (where x is 2 in binary system, 8 in octal system 10 in decimal system and 16 in hexadecimal system) In x-base system total x characters to represent a number e.g in Binary (base 2) 0 and 1 to represent a number , in octal 0 to 7, in decimal 0-9 and 0-9, A-F in hexadecimal system. xn-1 ……x3 x2 x1 x0 Integer . x-1 x-2 x-3 x-4 x-5……. x-m . Fractional
- 12. Course Title – Embedded Systems Design Topic# 1 INTRODUCTION TO COMPUTING 12 Number Representation Unsigned Number Representation Example of Decimal System ……. 103 102 101 100 ......1000 100 10 1 e.g a number in decimal system = (5003)10 = 5x103 + 0x102 + 0x101+ 3x100 Example of Binary System ……. 23 22 21 20 .....……8 4 2 1 e.g a number in binary = (1101) 2 In Decimal = 1x23 + 1x22 + 0x21+ 1x20 = 8+4+0+1= (13)10
- 13. Course Title – Embedded Systems Design Topic# 1 INTRODUCTION TO COMPUTING 13 Number Representation Unsigned Number Representation Range of Unsigned number = 2no. of bits – 1 e.g. if no. of bits are 3 then range is = 23 – 1 = 7 22 21 20 Decimal Number 0 0 0 0 0 0 1 1 0 1 0 2 0 1 1 3 1 0 0 4 1 0 1 5 1 1 0 6 1 1 1 7
- 14. Course Title – Embedded Systems Design Topic# 1 INTRODUCTION TO COMPUTING 14 Number Representation Signed Number Representation Signed Magnitude Representation S 21 20 Decimal Number 0 0 0 +0 0 0 1 +1 0 1 0 +2 0 1 1 +3 1 0 0 -0 1 0 1 -1 1 1 0 -2 1 1 1 -3 Decimal Number 0 0 0 +0 0 0 1 +1 0 1 0 +2 0 1 1 +3 1 0 0 -3 1 0 1 -2 1 1 0 -1 1 1 1 -0 1’s Compliment Representation
- 15. Course Title – Embedded Systems Design Topic# 1 INTRODUCTION TO COMPUTING 15 Number Representation Signed Number Representation -22 21 20 Decimal Number 0 0 0 +0 0 0 1 +1 0 1 0 +2 0 1 1 +3 1 0 0 -4 1 0 1 -3 1 1 0 -2 1 1 1 -1 2’s Compliment Representation Range = -2no. of bits-1 to 2no. of bits-1 – 1 e.g. if no. of bits are 3 then range is = -23-1 to 23-1 – 1 = -4 to +3
- 16. Course Title – Embedded Systems Design Topic# 1 INTRODUCTION TO COMPUTING 16 • Gates • Decision Making Operators • Number Representation • Adder/Subtractor • Memorizing Elements • Towards a Processor • Inside the CPU Outline
- 17. Course Title – Embedded Systems Design Topic# 1 INTRODUCTION TO COMPUTING 17 Arithmetic Operators 1- Bit Binary Half Adder A B S C 0 0 0 0 0 1 1 0 1 0 1 0 1 1 0 1 S C Half Adder S C A B Note: Operand of One Bits Total Sum of two bits i.e 1 bit sum and 1 bit carry Adder/Subtractor
- 18. Course Title – Embedded Systems Design Topic# 1 INTRODUCTION TO COMPUTING 18 Arithmetic Operators 1- Bit Binary Full Adder 4 - Bit Binary Full Adder Full Adder S Carry Out A B Carry In A B Cin S Cout 0 0 0 0 0 0 0 1 1 0 0 1 0 1 0 0 1 1 0 1 1 0 0 1 0 1 0 1 0 1 1 1 0 0 1 1 1 1 1 1 S4 Overview
- 19. Course Title – Embedded Systems Design Topic# 1 INTRODUCTION TO COMPUTING 19 Adder/Subtractor Subtractor: To get C = A-B we can do C= A + (-B) How –B can be achieved • Take 1’s Complement of ‘B’ by inverting each bit • Add 1 to 1’s complement of ‘B’ Can we modify adder circuit to behave as combined adder/subtractor.??? Yes why not … Arithmetic Operators
- 20. Course Title – Embedded Systems Design Topic# 1 INTRODUCTION TO COMPUTING 20 Arithmetic Operators Adder/Subtractor Combined Adder/Subtractor: 1. When addition we need Cin = 0 and B is transferred as it is to FA. 2. When subtraction is required we put Cin = 1 and it do two things: 1. Inverts each bit of B as b xor 1 = b’ 2. Add one to result as Cin = 1 3. Hence S = A + (B’ + 1) = A + (- B) And this is what we need to perform 2’s complement of B
- 21. Course Title – Embedded Systems Design Topic# 1 INTRODUCTION TO COMPUTING 21 • Gates • Decision Making Operators • Number Representation • Adder/Subtractor • Memorizing Elements • Towards a Processor • Inside the CPU Outline
- 22. Course Title – Embedded Systems Design Topic# 1 INTRODUCTION TO COMPUTING 22 Flip-Flops without /with enable Memorizing Elements • Reset Pin: to force Flip-Flop contents to 0. • Clk Pin: When rising or falling edge of the clock only then output is updated and this happens once in a clk period. • Enable : if enable is 1 and when rising or falling edge of the clock only then output is updated and this happens once in a clk period. d
- 23. Course Title – Embedded Systems Design Topic# 1 INTRODUCTION TO COMPUTING 23 4 bit - Registres Memorizing Elements
- 24. Course Title – Embedded Systems Design Topic# 1 INTRODUCTION TO COMPUTING 24 4 Bit 4 Location Memory Memorizing Elements
- 25. Course Title – Embedded Systems Design Topic# 1 INTRODUCTION TO COMPUTING 25 • Gates • Decision Making Operators • Number Representation • Adder/Subtractor • Memorizing Elements • Towards a Processor • Inside the CPU Outline
- 26. Course Title – Embedded Systems Design Topic# 1 INTRODUCTION TO COMPUTING 26 Small Processor Towards a Processor
- 27. Course Title – Embedded Systems Design Topic# 1 INTRODUCTION TO COMPUTING 27 Small Processor Towards a Processor ALU and Controller 32 4 24 4 rd_adr1 rd_data1 24 wr_adr1 wr_data1 1 wr_en1 4 24 4 rd_adr2 rd_data2 24 wr_adr2 wr_data2 1 wr_en2 Instr Instr. Memory Counter 4 adr Data Memory 1 Data Memory 2 Processor Outputs clk reset
- 28. Course Title – Embedded Systems Design Topic# 1 INTRODUCTION TO COMPUTING 28 • Gates • Decision Making Operators • Number Representation • Adder/Subtractor • Memorizing Elements • Towards a Processor • Inside the CPU Outline
- 29. Course Title – Embedded Systems Design Topic# 1 INTRODUCTION TO COMPUTING 29 Inside The Computer Important terminology related to memory of a computer Bit (0 or 1) Word (16 bits) Nibble (4 bits) Byte (8 bits) 0 0000 0000 0000 0000 0000 0000 0000 • Bit is a binary digit which can take value 0 or 1 • Nibble also known as Half Byte consists of 4 bits. • Byte is of 8 bits. • Word is of 2 bytes or 16 bits. They can be composed of any combination of zeros and ones.
- 30. Course Title – Embedded Systems Design Topic# 1 INTRODUCTION TO COMPUTING 30 Memory Types Two types of memory are commonly used in a computer Random Access(RAM) Read Only Memory Volatile Memory Non-Volatile Memory • RAM is used by the computer for the temporary storage of programs that it is running. • ROM contains programs and information essential to operation of the computer. Data is lost when power turned off Data is not lost when power turned off
- 31. Course Title – Embedded Systems Design Topic# 1 INTRODUCTION TO COMPUTING 31 Internal Organization of Computer Internal working of computer can be broken into three parts Central Processing Unit (CPU) Memory Input/Output (I/O)Devices • Bus inside a computer carries information from place to place just as a street bus carries people from place to place. It executes information stored in memory. It provide means of communicating with CPU via bus.
- 32. Course Title – Embedded Systems Design Topic# 1 INTRODUCTION TO COMPUTING 32 Data Bus • Data Buses are used to carry information in and out of a CPU. • They provide a better pathway between the CPU and its external devices (RAM, ROM, Printers etc.) • Analogy: Data buses can be thought of as Highway Lanes, more lanes means more traffic can pass. • Construction of more lanes (more data buses) result in expensive infrastructure (CPU and computer). • Data buses are bidirectional. CPU can either use it to receive or send data. • Processing power of computer is related to size of the data buses. • 8 bit bus can send out 1 byte at a time. • 16 bit can send out 2 bytes at a time, two times faster. • Average size of data buses in CPUs between 8 and 64.
- 33. Course Title – Embedded Systems Design Topic# 1 INTRODUCTION TO COMPUTING 33 Address Bus • Address Buses are used to identify the devices and memory connected to CPU. • More addresses buses available means larger number of devices can be addressed. • Number of address buses for a CPU determines the number of locations with which it can communicate. • The number of locations is always equal to 2x, x is the number of address lines. • A CPU with 16 address lines provide a total of 65,536 (216) or 64K of addressable memory. • Each location can have a maximum of 1 byte of data. This is because all general-purpose microprocessor CPUs are what is called byte addressable. • Address bus is unidirectional, CPU only uses address bus to send out addresses.
- 34. Course Title – Embedded Systems Design Topic# 1 INTRODUCTION TO COMPUTING 34 Control Bus • Control Buses are used to provide read or write signals to the device to indicate if the CPU is asking for information or sending information. • Control bus is unidirectional. Internal Organization of a Computer
- 35. Course Title – Embedded Systems Design Topic# 1 INTRODUCTION TO COMPUTING 35 Inside the CPU Internal Block Diagram of a CPU
- 36. Course Title – Embedded Systems Design Topic# 1 INTRODUCTION TO COMPUTING 36 Inside the CPU • A program stored in memory provides instructions to the CPU to perform an action. Action can simply be adding data or controlling a machine like a robot. • Function of the CPU is to fetch these instructions from memory and execute them. • Resources used by CPU to perform fetch and execute are: • CPU uses registers to store the information temporarily. The information could be values to be processed or the address of the value needed to be fetched from the memory. • Registers inside the CPU can be 8 bit, 16 bit, 32 bit or 64 bit registers. More and bigger the registers, the better the CPU. More and bigger registers means expensive CPUs.
- 37. Course Title – Embedded Systems Design Topic# 1 INTRODUCTION TO COMPUTING 37 Inside the CPU • Arithmetic Logical Unit (ALU) is responsible for performing arithmetic functions such as add, subtract, multiply, and divide, and logical functions such as AND, OR, and NOT. • The function of the program counter is to point to the address of the next instruction to be executed. • The function of the instruction decoder is to interpret the instruction fetched into the CPU. It is just a kind of dictionary, storing the meaning of each instruction and what steps the CPU should take upon receiving a given instruction.