Definition of Embedded Systems 1.Embedded system: is a system whose principal function is not computational, but which is controlled by a computer embedded within it. 2. A general computer is defined not to be an embedded system. 3. An Embedded system is some combination hardware and software,either fixed in capability or programmable,that is specifically designed for a particular function. 4.Any hardware system which is intended to do a specific task can be called as embedded system
1.The situation we find ourselves today in the field of microcontroller had its beginnings in the development of technology of integrated circuit. 2.This development has enabled us to store hundreds of thousands of transistors into one chip. 3.The first computers were made by adding external peripherals such as memory,input /output line, timers and others to it. 4. Further increasing of package density resulting in creating an integrated circuit which contained processor & peripherals.That is how the first chip containing a microcomputer later known as MICROCONTROLLER has developed.
Home Automation, Networking, and Entertainment Lab Dept. of Computer Science and Information Engineering National Cheng Kung University, TAIWAN Chung-Ping Young 楊中平 8051 MICROCONTROLLERS The 8051 Microcontroller and Embedded Systems: Using Assembly and C Mazidi, Mazidi and McKinlayDepartment of Computer Science and Information Engineering National Cheng Kung University, TAIWAN 2 HANEL OUTLINES Microcontrollers and embedded processors Overview of the 8051 familyDepartment of Computer Science and Information Engineering National Cheng Kung University, TAIWAN 3 HANEL MICROCONTROLLERS AND EMBEDDED PROCESSORS Microcontroller vs. GeneralPurpose Microprocessor General-purpose microprocessors contains ¾ No RAM ¾ No ROM ¾ No I/O ports Microcontroller has ¾ CPU (microprocessor) ¾ RAM ¾ ROM ¾ I/O ports ¾ Timer ¾ ADC and other peripheralsDepartment of Computer Science and Information Engineering National Cheng Kung University, TAIWAN 4 HANEL MICROCONTROLLERS AND EMBEDDED PROCESSORS Microcontroller vs. GeneralPurpose Microprocessor (cont’) Serial COM Port I/O Timer CPU RAM ROM Microcontroller CPU RAM Address bus Data bus ROM I/O Port Serial COM Port Timer Generalpurpose MicroProcessorDepartment of Computer Science and Information Engineering National Cheng Kung University, TAIWAN 5 HANEL MICROCONTROLLERS AND EMBEDDED PROCESSORS Microcontroller vs. GeneralPurpose Microprocessor (cont’) General-purpose microprocessorsgarage door openers, answering machines, fax machines, home computers, TVs, cable TV tuner, VCR, camcorder, remote controls, video games, cellular phones, musical instruments, sewing machines, lighting control, paging, camera, pinball machines, toys, exercise equipment Office ¾ Telephones, computers, security systems, fax machines, microwave, copier, laser printer, color printer, paging Auto ¾ Trip computer, engine control, air bag, ABS, instrumentation, security system, transmission control, entertainment, climate control, cellular phone, keyless entryDepartment of Computer Science and Information Engineering National Cheng Kung University, TAIWAN 8 HANEL MICROCONTROLLERS AND EMBEDDED PROCESSORS x86 PC Embedded Applications Many manufactures of general-purpose microprocessors have targeted their microprocessor for the high end of the embedded market ¾ There are times that a microcontroller is inadequate for the task When a company targets a generalpurpose microprocessor for the embedded market, it optimizes the processor used for embedded systems Very often the terms embedded processor and microcontroller are used interchangeablyDepartment of Computer National Cheng Kung University, TAIWAN 9 AND EMBEDDED PROCESSORS x86 PC Embedded Serial er UV-EPROM eraser takes 20 min to erase AT89C51 from Atmel Corporation CPU On-chip RAM On-chip ROM for program code 4 I/O Ports Timer 0 Serial Port OSC Interrupt Control External interrupts Timer 1 Timer/Counter Bus Control TxD RxD P0 P1 P2 P3 Address/Data Counter Inputs
In this project the robot, is controlled by a mobile phone that makes call to the mobile phone attached to the robot in the course of the call, if any button is pressed control corresponding to the button pressed is heard at the other end of the call. This tone is called dual tone multi frequency tone (DTMF)robot receives this DTMF tone with the help of phone stacked in the robot The received tone is processed by the microcontroller with the help of DTMF decoder MT8870 the decoder decodes the DTMF tone in to its equivalent binary digit and this binary number is send to the microcontroller, the microcontroller is pre programmed to take a decision for any given input and outputs its decision to motor drivers in order to drive the motors for forward or backward motion or a turn.
The mobile that makes a call to the mobile phone stacked in the robot acts as a remote. So this simple robotic project does not require the construction of receiver and transmitter units. DTMF signalling is used for telephone signalling over the line in the voice frequency band to the call switching centre. The version of DTMF used for telephone dialling is known as touch tone. DTMF assigns a specific frequency (consisting of two separate tones) to each key s that it can easily be identified by the electronic circuit. The signal generated by the DTMF encoder is the direct alzebric submission, in real time of the amplitudes of two sine(cosine) waves of different frequencies, i.e.,pressing 5 will send a tone made by adding 1336hz and 770hz to the other end of the mobile.
APLLICATIONS 1) Scientific Remote control vehicles have various scientific uses including hazardous environments, working in the deep ocean, and space exploration. The majority of the probes to the other planets in our solar system have been remote control vehicles, although some of the more recent ones were partially autonomous. The sophistication of these devices has fueled greater debate on the need for manned spaceflight and exploration. 2) Military and Law Enforcement Military usage of remotely controlled military vehicles dates back to the first half of 20th century. Soviet Red Army used remotely controlled Tele tanks during 1930s in the Winter War and early stage of World War II.
3) Search and Rescue UAVs will likely play an increased role in search and rescue in the United States. This was demonstrated by the successful use of UAVs during the 2008 hurricanes that struck Louisiana and Texas. 4) Recreation and Hobby See Radio-controlled model. Small scale remote control vehicles have long been popular among hobbyists. These remote controlled vehicles span a wide range in terms of price and sophistication. There are many types of radio controlled vehicles. These include on-road cars, off-road trucks, boats, airplanes, and even helicopters. The "robots" now popular in television shows such as Robot Wars, are a recent extension of this hobby (these vehicles do not meet the classical definition of a robot; they are remotely controlled by a human).
FURTHER IMROVEMENTS & FUTURE SCOPE 1. IR Sensors: IR sensors can be used to automatically detect & avoid obstacles if the robot goes beyond line of sight. This avoids damage to the vehicle if we are maneuvering it from a distant place. 2. Password Protection: Project can be modified in order to password protect the robot so that it can be operated only if correct password is entered. Either cell phone should be password protected or necessary modification should be made in the assembly language code. This introduces conditioned access & increases security to a great extent.
3. Alarm Phone Dialer: By replacing DTMF Decoder IC CM8870 by a 'DTMF Transceiver IC’ CM8880, DTMF tones can be generated from the robot. So, a project called 'Alarm Phone Dialer' can be built which will generate necessary alarms for something that is desired to be monitored (usually by triggering a relay). For example, a high water alarm, low temperature alarm, opening of back window, garage door, etc. When the system is activated it will call a number of programmed numbers to let the user know the alarm has been activated. This would be great to get alerts of alarm conditions from home when user is at work. 4. Adding a Camera: If the current project is interfaced with a camera (e.g. a Webcam) robot can be driven beyond line-of-sight & range becomes practically unlimited as GSM networks have a very large range.