Microprocessor & Interfacing Techniques. HISTORY OF MICROPROCESSORS Computers are accessible to ever-increasing sectors of the world's population

Microprocessor & Interfacing Techniques

HISTORY OF MICROPROCESSORS

Computers are accessible to ever-increasing sectors of the world's population.

Computing hardware has become a platform for uses other than computation, such as automation, communication, control, entertainment, and education.


Types of Computers

Mainframes Minicomputers Microcomputers


Mainframes:

The largest and most powerful computers are called Mainframes.

They are designed to work at a very high speeds with large data words, typically 64 bits or greater.

Examples are IBM 4381, Honeywell DPS8, Cray Y-MP/832


Minicomputers:

Scaled down version of mainframe computers are often called minicomputers.

A minicomputer runs slowly, works directly with smaller data words.

Computers of this type are used for business data processing, industrial control and scientific research.

Examples are DEC VAX-6360, Data General MV/8000II


Microcomputers:

They are the small computers.

There are wide range of microcomputers depending on their specification.

Some microcomputers have all or most of the features of earlier minicomputers.

Microcomputer consist of a CPU ( usually a single integrated circuit) called a microprocessor.

Examples are Intel 80-51 single-chip controller, SDK-86, IBM PC, Apple Macintosh.


What is a Micro-processor?

A Microprocessor is used as a CPU in a microcomputer.

A semiconductor chip or chip set that forms the CPU

Controls computers input/output devices Executes programs


Microprocessor unit (MPU) Consists of an arithmetic logic unit (ALU), a

control unit, an instruction decoder and some registers.

The MPU Works by sequentially decoding instructions and operating on data under control of a program.

The instructions and the data are stored in memory.


The “Microprocessor” term was used by Intel to name their first CPU (4004). A 4-bit chip designed to be used in a calculator.

Architectures now have advanced to 8, 16, 32, 64-bit for general purpose CPUs, and 128/256-bit and higher for specialised microprocessors such as GPUs, DSPs.

Term now used to describe the core component of a computer, the “brains” of the system that controls all the rest of the components, the peripherals.



• The date is the year that the processor was first introduced. Many processors are re-introduced at higher clock speeds for many years after the original release date.

• Transistors is the number of transistors on the chip. You can see that the number of transistors on a single chip has risen steadily over the years.

• Microns is the width, in microns, of the smallest wire on the chip. For comparison, a human hair is 100 microns thick. As the feature size on the chip goes down, the number of transistors rises.


• Clock speed is the maximum rate that the chip can be clocked at. Clock speed will make more sense in the next section.

• Data Width is the width of the ALU. An 8-bit ALU can add/subtract/multiply/etc. two 8-bit numbers, while a 32-bit ALU can manipulate 32-bit numbers. An 8-bit ALU would have to execute four instructions to add two 32-bit numbers, while a 32-bit ALU can do it in one instruction. In many cases, the external data bus is the same width as the ALU, but not always. The 8088 had a 16-bit ALU and an 8-bit bus, while the modern Pentiums fetch data 64 bits at a time for their 32-bit ALUs.


MIPS stands for "millions of instructions per second" and is a rough measure of the performance of a CPU. Modern CPUs can do so many different things that MIPS ratings lose a lot of their meaning, but you can get a general sense of the relative power of the CPUs from this column.

MICROPROCESSOR

Microprocessor v Microcomputer

A Microprocessor only is a single-chip CPU bus is available RAM capacity, num of port is selectable Communicate by port

A Microcomputer contains a CPU and RAM,ROM ,Peripherals, I/O port in a single IC internal hardware is fixed Communicate by port ROM is larger than RAM (usually) Small power consumption Single chip, small board Implementation is easy Low cost

Microprocessor V Microcomputers

Applications

Microcomputers are suitable to control I/O devices in designs requiring a minimum component

Microprocessors are suitable for processing information in computer systems.


Microcomputer is easy to use and design. Only single chip can be a complete system interfacing to other devices, for example, motors,

displays, sensors, and communicate with PC.

In contrast, similar system that builds from Microprocessor would require a lot of additional units, such as RAM, UART, I/O , TIMER and etc.


Logic circuit provides limited function for one single design. In order to change circuit’s functionality, we need to redesign the circuits.

Microcomputers can reprogram and change functionality of every port, input to output or digital to analog on the fly.

The Microcomputers

All Microcomputers consist of (at least) : Microprocessor Unit (MPU) Program Memory (ROM) Data Memory (RAM) Input / Output ports Bus System (and Software)

MPU is the brain of microcomputer

Microcomputers

Many microcomputers are existing right now. 8051, 68HC11, MSP430, ARM series, and etc.

We may widely divide it with how it is designed RISC/CISC architecture.

What is the main difference between

RISC/CISC? Does it make any difference to our

application?

A Microcomputer

The Microprocessor (MPU)

The microprocessor is the ‘brain of the microcomputer’

Is a single chip which is capable of processing data controlling all of the components which make up the

microcomputer system

µP used to sequence executions of instructions that is in memory

µP Fetch , Decode , and Execute the instruction The internal architecture of the microprocessor is

complex.

The Microprocessor (MPU)

Microprocessor (MPU) typically contains Registers: Temporary storage locations for program

instruction or data.

The Arithmetic Logic unit (ALU): This part of the MPU

performs both arithmetic and logical operations

Timing and Control Circuits: that keep all of the other

parts of system (Regs, ALU, memory & I/O) working

together in the right time sequence

MICROPROCESSORS

Using its ALU (Arithmetic/Logic Unit), a microprocessor can perform mathematical operations like addition, subtraction, multiplication and division. Modern microprocessors contain complete floating point processors that can perform extremely sophisticated operations on large floating point numbers.

2. A microprocessor can move data from one memory location to another.

3. A microprocessor can make decisions and jump to a new set of instructions based on those decisions.

The Input/Output (I/O) System

I/O is the link between the MPU and the outside world.

An input port is a circuit through which an external device can send signals (data?) to the MPU.

An output port is a circuit that allows the MPU to send signals (data?) to external devices.

I/O ports connect both digital and analogue devices by DAC and ADC

BUS

A Bus is a common communications pathway used to carry information between the various elements of a computer system

The term BUS refers to a group of wires or conduction tracks on a printed circuit board (PCB) though which binary information is transferred from one part of the microcomputer to another

The individual subsystems of the digital computer are connected through an interconnecting BUS system.

Types of Buses

There are three main bus groups

ADDRESS BUS DATA BUS CONTROL BUS

Data Bus

The Data Bus carries the data which is transferred throughout the system. ( bi-directional)

Examples of data transfers Program instructions being read from memory into MPU. Data being sent from MPU to I/O port Data being read from I/O port going to MPU Results from MPU sent to Memory

These are called read and write operations

Address Bus

An address is a binary number that identifies a specific memory storage location or I/O port involved in a data transfer

The Address Bus is used to transmit the address of the location to the memory or the I/O port.

The Address Bus is unidirectional (one way): addresses are always issued by the MPU.

Control Bus

The Control Bus: is another group of signals whose functions are to provide synchronization ( timing control ) between the MPU and the other system components.

Control signals are unidirectional, and are mainly outputs from the MPU.

Example Control signals RD: read signal asserted to read data into MPU WR: write signal asserted to write data from MPU

Main Memory

The duties of the memory are : To store programs To provide data to the MPU on request To accept result from the MPU for storage

Main memory Types ROM : read only memory. Contains program

(Firmware). does not lose its contents when power is removed (Non-volatile)

RAM: random access memory (read/write memory) used as variable data, loses contents when power is removed volatile. When power up will contain random data values

Read only Memory

Microprocessor can read instructions from ROM quickly

Cannot write new data to the ROM ROM remembers the data, even after power

cycled Typically, when the power is turned on, the

microprocessor will start fetching instructions from the still-remembered program in ROM (bootstrap )

Types of ROMS

Masked ROM or just ROM PROM or programmable ROM(once only) EPROM (erasable via ultraviolet light) Flash (can be erased and re-written about 10000

times, usually must write a whole block not just 1 byte or 2 bytes, slow writing, fast reading)

EEPROM (electrically erasable read-only memory, also known as EEROM—both reading and writing are very slow but can program millions of times…useless for storing a program but good for say configuration information.

ROM

On a PC, the ROM is called the BIOS (Basic Input/Output System). When the microprocessor starts, it begins executing instructions it finds in the BIOS. The BIOS instructions do things like test the hardware in the machine, and then it goes to the hard disk to fetch the boot sector. This boot sector is another small program, and the BIOS stores it in RAM after reading it off the disk. The microprocessor then begins executing the boot sector's instructions from RAM. The boot sector program will tell the microprocessor to fetch something else from the hard disk into RAM, which the microprocessor then executes, and so on. This is how the microprocessor loads and executes the entire operating system.

Conclusion

You should be able to define terms microcomputer, microprocessor, computer types, memory, bus, input/output devices.

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Microprocessor & Interfacing Techniques. HISTORY OF MICROPROCESSORS Computers are accessible to ever-increasing sectors of the world's population