Microcontroller: Introduction Lecturer: Kalamullah Ramli Fundamental of Computer Engineering Departement of Electrical Engineering University of Indonesia Microcontroller: Introduction

Outline What is Microcontroller Microprocessor vs Microcontroller Some Types of Microcontroller MCS51 Features AT89C51 Basic Features, Architecture Sample Application

What is Microcontroller? (1/7) Microcontrollers are hidden inside a surprising number of products these days Basically, any product or device that interacts with its user has a microcontroller buried inside A microcontroller is a computer All computers -- whether we are talking about a personal desktop computer or a large mainframe computer or a microcontroller -- have several things in common:

What is Microcontroller? (2/7) All computers have a CPU (central processing unit) that executes programs If you are sitting at a desktop computer right now reading this article, the CPU in that machine is executing a program that implements the power point that is displaying this page. The CPU loads the program from somewhere. On your desktop machine, the browser program is loaded from the hard disk The computer has some RAM (random-access memory) where it can store "variables" The computer has some input and output devices so it can talk to people.

What is Microcontroller? (3/7) The desktop computer we are using is a "general purpose computer“ It can run any of thousands of programs Microcontrollers are "special purpose computers" Microcontrollers do one thing well There are a number of other common characteristics that define microcontrollers If a computer matches a majority of these characteristics, then you can call it a "microcontroller": Microcontrollers are "embedded" inside some other device (often a consumer product) so that they can control the features or actions of the product

What is Microcontroller? (4/7) Another name for a microcontroller, therefore, is "embedded controller" Microcontrollers are dedicated to one task and run one specific program The program is stored in ROM (read-only memory) and generally does not change Microcontrollers are often low-power devices. A desktop computer is almost always plugged into a wall socket and might consume 50 watts of electricity A battery-operated microcontroller might consume 50 milliwatts

What is Microcontroller? (5/7) A microcontroller has a dedicated input device and often (but not always) has a small LED or LCD display for output A microcontroller also takes input from the device it is controlling and controls the device by sending signals to different components in the device. The microcontroller inside a TV takes input from the remote control and displays output on the TV screen The controller controls the channel selector, the speaker system and certain adjustments on the picture tube electronics such as tint and brightness

What is Microcontroller? (6/7) The engine controller in a car takes input from sensors such as the oxygen and knock sensors and controls things like fuel mix and spark plug timing A microwave oven controller takes input from a keypad, displays output on an LCD display and controls a relay that turns the microwave generator on and off A microcontroller is often small and low cost The components are chosen to minimize size and to be as inexpensive as possible

What is Microcontroller? (7/7) A microcontroller is often, but not always, ruggedized in some way The microcontroller controlling a car's engine, for example, has to work in temperature extremes that a normal computer generally cannot handle A car's microcontroller in Alaska has to work fine in -30 degree F (-34 C) weather, while the same microcontroller in Nevada might be operating at 120 degrees F (49 C) On the other hand, a microcontroller embedded inside a VCR hasn't been ruggedized at all

Microprocessor vs Microcontroller General purpose Vs Dedicated Machine A MicroProcessor is a general purpose machine while a MicroController is a dedicated machine Embedded Systems MicroProcessors need external RAM and ROM for a complete system; while most of the MicroControllers have built in RAM and ROMs ( Nowadays EEPROMs ) “No Direct Talk” Vs “Direct Talk” (Interface) MicroProcessors cannot directly “talk” or interfaced to outside world; they need chips to do so e.g. 8255 for Parallel Communication and 8251 for Serial Communication (for Intel Systems). MicroController have dedicated ports for these interfaces e.g. Port 1 and RxD & TxD of 89C51

Low-end Microcontroller Components 20 bytes of RAM 1000 bytes of ROM 8 I/O Pins

Some Types of Microcontroller Z-80 Usually contained in a Digital Cell Phone 8-bit Microprocessor Motorolla e.g., in Microwave Oven Intel 8051 Good for dedicated purpose Programmer Interface Controller (PIC) by Microchip

Various Microcontrollers in MCS51 Family

8051 Features 8051 was developed by Intel in the late 80’s Newer versions can contain USB interfaces, Ethernet, Data Acquisition Systems, Flash, etc "New high performance single chip microprocessors" 8 bit 12 MHz Harvard Architecture 4k ROM 128 bytes RAM 32 i/o lines 2 counter/timers 1 serial port

8051 Features 1 serial port bit manipulation instructions hardware multiply & divide 4usec 64k address space program 64k address data 12 clocks per instruction 1 MIPS 8751 (Ceramic EPROM version $25.00) Newer versions range from a few dollars (a small footprint chip), to over a hundred (complete with battery backup, clock, ram, software download, etc) dollars.

AT89C51 Basic Features 4 K Bytes ROM 128 Bytes RAM Four 8-bit I/O Ports Two 16 Bit Timers Serial Interface 64 K External Code Memory Space 64 K External Data Memory Space Boolean processor (operates on single bits) 210 Bit Addressable Locations 4 Microseconds Multiply / Divide

AT89C51 Internal Architecture

AT89C51 Pinouts Diagram

Motor Control Demonstration: Block Diagram

Motor Control Demonstration: Circuit Diagram

Motor Control Demonstration: Progr. List

Motor Control Demonstration: Progr. List

TO BE CONTINUED