MicroProcessor

Microprocessors And Its Real-timeApplications

Vijetha V

Akshatha Kini

Vinutha Pai K

Sushma Baliga B

February 16, 2009

Contents

1 Introduction 3

2 Applications 4

2.1 Traffic light control and information transmission device . . . . . . . 4

2.2 Camera with microprocessor . . . . . . . . . . . . . . . . . . . . . . . 6

2.3 Microwave oven control with external memory control data . . . . . . 7

2.4 Water temperature control system for a washing machine . . . . . . . 8

2.5 Toy airplane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

2.6 Microprocessor applications in the nuclear industry . . . . . . . . . . 9

3 Conclusion 10

February 16, 2009 Microprocessors And Its Real-time Applications

1 Introduction

A microprocessor is a circuit that combines the instruction-handling, arithmetic, andlogical operations of a computer on a single chip. A microprocessor executes theprograms stored in main memory by fetching their instructions, examining them, andthen executing them one after another according to their programmatic order. Micro-processors may implement the technique of overlapping a fetching stage, a decodingstage, an execution stage and possibly a write back stage. These steps are controlledby a periodic clock signal. The period of the clock signal is the processor cycle time.A microprocessor receives instructions composing a program from a storage device,and decodes the instructions with the decoder to control its constituent device such asa calculation device, an input device, an output device, a storage device, or a controldevice depending on the contents of the instructions, thereby to proceed with theprocesses in sequence.

Microprocessors are used to handle a set of tasks that control one or more externalevents or systems. Microprocessors are typically used in either reactive or embeddedsystems.

Reactive systems are those that have an ongoing interaction with their environment- for example, a fire-control system that constantly reacts to buttons pressed by apilot.

Embedded systems are those used to control specialized hardware in which thecomputer system is installed - for example, the microprocessor system used to controlthe fuel/air mixture in the carburetor of many automobiles. In embedded systemsthe software system is completely encapsulated by the hardware that it controls.

Often the processor is required to manage various different tasks that have to bescheduled somehow and must also deal with outside interrupt sources such as analarm when something goes wrong.

Real-time systems are those in which timeliness is as important as the correctness ofthe outputs, although this does NOT mean that they have to be fast systems.

A real-time system does not have to process data in microseconds to be consideredreal-time - it must simply have response times that are constrained and thus pre-dictable.

Canara Engineering College, Mangalore 3


2 Applications

Some of the real time applications of microprocessor are explained below. The ex-plained applications are:

• Traffic lights

• Digital camera

• Microwave oven

• Water temperature control system for a washing machine

• Toy airplane

• Microprocessor applications in the nuclear industry

2.1 Traffic light control and information transmission device

A traffic light control and information transmission device compromising a micropro-cessor, traffic light controller, an electronic display board, a video camera, a compres-sion circuitry, an I/O interface, a traffic flow detector and DSL (Digital SubscriberLoop). The control signals, traffic, public information or news of the central trafficcontrol computer can go through the DSL to the microprocessor; the microprocessorcan control the traffic light and display all the information on the electronic displayboard. The traffic flow data of the cross roads can be accessed by the traffic flowdetector and the video camera and transmitted back to the central traffic controlcomputer. A representative diagram is shown in the figure below.

Figure 1: Repesentative Diagram



Detailed Description

Traffic light control and information transmission device that consists of a micro-processor on the cross road, the microprocessor further connects to a traffic lightcontroller, an electronic display board, a video camera, a compression circuitry, anI/O interface, a traffic flow detector which are connected to the central traffic controlcomputer through the DSL (Digital Subscriber Loop). The control signals, traffic,public information or news of the central traffic control computer can go throughthe DSL to the microprocessor; the microprocessor can control the traffic light anddisplay all the information on the electronic display board. The traffic flow data ofthe cross roads can be accessed by the traffic flow detector and the video cameraand transmitted back to the central traffic control computer. This scheme appliesthe existing broadband network to transmit data between the central traffic controlcomputer and the microprocessors of the cross roads to avoid the installation of thecables and save the construction cost.

Heretofore, it is known that a traffic light applies red, yellow and green light to controlthe traffic direction and flow, the control of the traffic light is done by the local controlbox or by the computer in the remote central traffic control office so that the trafficflow can be controlled under normal.

Cables and/or wires must be installed between every control box of the traffic lightand the central computer to transmit the control signals and data; two ways to installthe cables: above ground and underground.

It is therefore a primary object of the invention to provide a traffic light controland information transmission device that applies the existing broadband network totransmit data between the central traffic control computer and the microprocessorsof the cross roads to avoid the installation of the cables and save the constructioncost.

In order to achieve the objective set forth, a traffic light control and information trans-mission device in accordance with the present invention comprises a microprocessoron the cross road, the microprocessor further connects to a traffic light controller, anelectronic display board, a video camera, a compression circuitry, an I/O interface,a traffic flow detector and connected to the central traffic control computer throughthe DSL (Digital Subscriber Loop). The control signals, traffic, public information ornews of the central traffic control computer can go through the DSL to the micropro-cessor; the microprocessor can control the traffic light and display all the informationon the electronic display board.



2.2 Camera with microprocessor

A digital camera includes a photo sensor with a plurality of picture elements thatdefine an image resolution that is adjustable. The digital camera includes a micro-processor that provides for flexible operation of the digital camera. The micropro-cessor also provides the digital camera manufacturer the capability of economicallyconfiguring the digital camera as desired. The microprocessor also provides the digi-tal camera user with on demand specialized imaging modes such as the capture modeand the cine view mode.


The digital camera generally includes a lens or lens assembly attached to a body,and within the body there is a viewfinder, an aperture, a shutter, and a steppermotor for adjusting the lens assembly, aperture, and shutter. Also within the bodythere is an image capturing medium, a gain control device, an analog-to-digital (A-D)converter, a digital-to-analog (D-A) converter, a microprocessor, a memory controller,an internal memory unit, and a memory card. Display and control panels are providedon the body for input/output with the user. Power is provided by a power unit suchas a battery.

The digital camera is capable of operation in a variety of lighting conditions rangingfrom the very bright sunlit outdoors to very dimly lit or dark situations. Low-lightperformance of the digital camera is implemented in a variety of ways. The digitalcamera adjusts to low-light conditions by modifying one or more of the followingsettings: size of the aperture, speed of the shutter, gain from the image capturingmedium, and resolution capability of the image capturing medium.

The image capturing medium may be a complimentary metal oxide semiconductor(CMOS) sensor that is positioned behind the lens, aperture, and shutter within thebody of the camera. The image capturing medium encompasses any device or materialthat is capable of capturing radiant energy and at least partially capable of convertingsame into an electronic signal that becomes a virtual representation of the opticalimage projected onto the sensor by the lens assembly.

The gain control device is connected the CMOS sensor to amplify the electronicsignals. The gain control device may be a variable analog amplifier that is connectedbetween the A-D converter and the CMOS sensor to regulate the intensity of theelectronic signal passing from the CMOS sensor to the microprocessor via the A-Dconverter. The intensity of the signal is also regulated by the microprocessor viathe DA converter that is interposed the microprocessor and gain control device. TheA-D converter converts the amplified analog signals from the gain control device intodigital signals of acceptable levels that are appropriate for the microprocessor.



The low-light level performance of the digital camera can also be regulated by the gaincontrol device. The microprocessor can signal the gain control device to amplify thesignal from the CMOS sensor to make up for a weak signal due to low-light conditions,with some attendant amplification of inherent noise from the CMOS sensor. The gaincontrol device, aperture, and shutter may be adjustable together in any combinationor adjustable independently to constitute an image enhancement apparatus that isautomatically controlled by the microprocessor.

2.3 Microwave oven control with external memory controldata

A microwave control unit that includes external memory storage is for storing controlparameters, cooking parameters, and feature data. In one embodiment, the controlunit includes a pre-programmed microprocessor coupled to a key panel and a display.The controller also is coupled, to a power supply, sensors, and power switches. Thecontrol microprocessor includes an on-board memory unit, e.g., a read only memory,for storing the control program as well as control parameters, cooking parameters,and feature data. Under the control of the control program, the microprocessor isconfigured to control, energy output levels and cooking time based on the operatorinputs. The control unit also includes an external model configuration read onlymemory (EMCR) coupled to the control microprocessor via an external bus. TheEMCR also has control parameters, cooking parameters, and feature data stored.The parameters and data stored in the EMCR can differ in many respects from thecontrol program stored in the on-board memory.


Control unit includes a pre-programmed controller or control microprocessor, coupledto a key panel and a display. An operator may input instructions to controller viakey panel, and certain messages and data are displayed by controller on display. Forexample, the remaining time in a cooking cycle may be displayed by controller. Con-troller also is coupled, to a power supply, sensors, and power switches. Instructionsinput by an operator at key panel are utilized by controller in controlling cooking op-erations. Temperature representative signals are provided to controller by sensors sothat controller can determine whether the desired operation is being achieved. Con-troller includes an on-board memory unit, read only memory, for storing a controlprogram, control parameters, cooking parameters, and feature data.

Control unit also includes an external model configuration read only memory (EMCR)coupled to control microprocessor via an external bus. More particularly, EMCR isconfigured for serial communications with processor, which provides the advantagethat only two lines are needed for connecting EMCR to processor. The parameters



and data stored in EMCR can differ in many respects from the parameters and datastored in the on-board memory.

When EMCR is installed, processor uses only the parameters and data in EMCR.When EMCR is not installed, processor uses only the parameters and data stored inROM.

Control microprocessor and EMCR be mounted on the same printed circuit board.The printed circuit board would include a socket connector for receiving EMCR.EMCR can be removed and inserted into such socket connector when desired. EMCRis configured for serial communications with processor. Such serial communicationsprovides the advantage that only two lines are needed to connect EMCR to processor.

Illustrating process steps executed by control microprocessor, and upon initializationof control microprocessor, microprocessor attempts to read parameters or data fromEMCR. If the attempt to read from EMCR is successful, a requested parameter ordata is returned, and then processor continues with processing using the parametersand data set stored in EMCR. If the attempt is not successful, then processor usesthe parameters and data stored in on-board ROM.

The control unit therefore enables fast and easy conversion to modified parametersand data, and is believed to be less expensive than using specialized processors thatallow for revisions to parameters and data stored in the on-board memory.

Alternatively, and rather than a total redesign and change-out of an existing pro-cessor, the EMCR can be used to revise or add just a few or maybe even just onefunction. Such architecture enables creation of a base routine with a supplementalroutine both the base routine and the supplemental routine would be executed by theprocessor. Multiple supplemental routines could be generated and stored in EMCRsto enable reconfiguration of the processor control based on the oven model, ratherthan separate processor control programs for each model.

2.4 Water temperature control system for a washing machine

A microprocessor controlled water temperature control system is used in a washingmachine or dish washer. Average water fill temperature is calculated periodically and,with one water valve maintained in an on condition, the other water valve is cycled fora percentage on time as calculated by the microprocessor which is required to producean actual water fill temperature equal to the desired water temperature selected bythe user. The single water valve is cycled on and off repetitively over a predeterminedcycle time period with the percentage on time being recalculated for each cycle sothat the system is capable of adapting to changing inlet water temperatures.

This invention relates to washing machines and, more particularly, to automatic



washing machines that have a system for controlling the temperature of fill waterintroduced into the washing machine tub. Systems for providing selectable waterfill temperatures in, for example, clothes washers are well known. Sophisticated andexpensive systems employing temperature sensors and modulated valves have beenemployed while more economical systems that merely turn on one or both watervalves to achieve hot, cold or warm selection have also been employed.

2.5 Toy airplane

A toy airplane assembly is provided that is easy to fly, inexpensive, and durable.The toy plane assembly includes a plane having a radio receiver and a microproces-sor. Batteries housed in the fuselage power the printed circuit board to which themicroprocessor and radio receiver are attached. The radio receiver receives signalsfrom a hand-held remote control radio transmitter and signals are transmitted to themicroprocessor. The microprocessor decodes the signals and, in response, distributespower to the motors for driving the propellers. All movement of the plane is controlledby the microprocessor, thereby providing microprocessor assisted flight. The planefuselage is a one-piece molded part, made of a foam material to provide a durableplane.


The radio controlled plane assembly of the present invention is easy to fly. The planefuselage is a one-piece molded part.

Motors drive propellers positioned on the wing on opposite sides of the fuselage. Themicroprocessor and the radio receiver are attached to a printed circuit board housed inthe fuselage. Batteries supply power to the printed circuit board. The radio receiverlocated in the fuselage receives signals from radio transmitter in the hand-held remotecontrol. The signal triggered the microprocessors, which distributes power to themotors for driving the propellers. All the movement of the plane is controlled by themicroprocessor. The microprocessor assisted flight provides an easy to fly plane.

2.6 Microprocessor applications in the nuclear industry

Microprocessors in the nuclear industry, particularly at the los Al amos ScientificLaboratory, have been and are being utilized in a wide variety of applications rangingfrom data acquisition and control for basic physics research to monitoring specialnuclear material in long-term storage. Microprocessor systems have been developedto support weapons diagnostics measurements during underground weapons testing at



the Nevada Test Site. Multiple single-component microcomputers are now controllingthe measurement and recording of nuclear reactor operating power levels. The CMOSmicroprocessor data-acquisition instrumentation has operated on balloon flights tomonitor power plant emissions. Target chamber mirror-positioning equipment forlaser fusion facilities employs microprocessors.

3 Conclusion

Microprocessors have many more other real-time applications. Its covers almost allthe fields. Some other applications such as microprocessor used in lifts, in automobile,controlled signal transformer, cell phones, refrigerator, escalator. Other major fieldwhere microprocessor is used is in medical science that is in testing various surgicalinstruments. Even in manufacturing industry microprocessors are used, example tofill in the exact amount of liquid into the containers. The containers are made tomove on a conveyor belt and the exact quantity is filled in and sealed. All this ispossible due to programmed processor. Microprocessors are programmed as per therequirements for the job to be completed successfully.

References

www.freepatentsonline.comwww.silicavalley.comwww.howstuffswork.com


http://www.freepatentsonline.com

http://www.silicavalley.com

http://www.howstuffswork.com

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