The main aim of this project is to design a Traffic light controller using 8085 microprocessor, interfacing with peripheral device 8085, and program implementing the process.IntroductionThe 8085 Microprocessor is a popular Microprocessor used in Industries for various applications. Such as traffic light control, temperature control, stepper motor control, etc. In this project, the traffic lights are interfaced to Microprocessor system through buffer and ports of programmable peripheral Interface 8255. So the traffic lights can be automatically switched ON/OFF in desired sequence. The Interface board has been designed to work with parallel port of Microprocessor system.The hardware of the system consists of two parts. The first part is Microprocessor based system with 8085. Microprocessor as CPU and the peripheral devices like EPROM, RAM, Keyboard & Display Controller 8279, Programmable as Peripheral Interface 8255, 26 pin parallel port connector, 21 keys Hexa key pad and six number of seven segment LED's.The second part is the traffic light controller interface board, which consist of 36 LED's in which 20 LED's are used for vehicle traffic and they are connected to 20 port lines of 8255 through Buffer. Remaining LED's are used for pedestrian traffic. The traffic light interface board is connected to Main board using 26 core flat cables to 26-pin Port connector. The LED's can be switched ON/OFF in the specified sequence by the Microprocessor. Get Help With Your EssayIf you need assistance with writing your essay, our professional essay writing service is here to help!
traffic light controller using 8085 microprocessor pdf free 21
The normal function of traffic lights requires sophisticated control and coordination to ensure that traffic moves as smoothly and safely as possible and that pedestrians are protected when they cross the roads. A variety of different control systems are used to accomplish this, ranging from simple clockwork mechanisms to sophisticated computerized control and coordination systems that self-adjust to minimize delay to people using the road.Traffic Controller SystemsA traffic signal is typically controlled by a controller inside a cabinet mounted on a concrete pad. Although some electro-mechanical controllers are still in use (New York City still has 4,800), modern traffic controllers are solid state. The cabinet typically contains a power panel, to distribute electrical power in the cabinet; a detector interface panel, to connect to loop detectors and other detectors; detector amplifiers; the controller itself; a conflict monitor unit; flash transfer relays; a police panel, to allow the police to disable the signal; and other components.Fixed Time ControlThe simplest control system uses a timer (fixed-time): each phase of the signal lasts for a specific duration before the next phase occurs; this pattern repeats itself regardless of traffic. Many older traffic light installations still use these, and timer-based signals are effective in one way grids where it is often possible to coordinate the traffic lights to the posted speed limit. They are however disadvantageous when the signal timing of an intersection would profit from being adapted to the dominant flows changing over the time of the day.Dynamic ControlDynamic, or actuated, signals are programmed to adjust their timing and phasing to meet changing traffic conditions. The system adjusts signal phasing and timing to minimize the delay of people going through the intersection. It is also commonplace to alter the control strategy of a traffic light based on the time of day and day of the week, or for other special circumstances such as a major event causing unusual demand at an intersection.The controller uses input from detectors, which are sensors that inform the controller processor whether vehicles or other road users are present, to adjust signal timing and phasing within the limits set by the controllersprogramming. It can give more time to an intersection approach that is experiencing heavy traffic, or shorten or even skip a phase that has little or no traffic waiting for a green light. Detectors can be grouped into three classes: in-pavement detectors, non-intrusive detectors, and detection for non-motorized road users.Working ProgramDesign of a microprocessor system to control traffic lights. The traffic should be controlled in the following manner.1) Allow traffic from W to E and E to W transition for 20 seconds. 2) Give transition period of 5 seconds (Yellow bulbs ON) 3) Allow traffic from N to 5 and 5 to N for 20 seconds 4) Give transition period of 5 seconds (Yellow bulbs ON) 5) Repeat the process.Source Program:MVI A, 80H: Initialize 8255, port A and port BOUT 83H (CR): in output modeSTART: MVI A, 09HOUT 80H (PA): Send data on PA to glow R1 and R2MVI A, 24HOUT 81H (PB): Send data on PB to glow G3 and G4MVI C, 28H: Load multiplier count (40ıο) for delayCALL DELAY: Call delay subroutineMVI A, 12HOUT (81H) PA: Send data on Port A to glow Y1 and Y2OUT (81H) PB: Send data on port B to glow Y3 and Y4MVI C, 0AH: Load multiplier count (10ıο) for delayCALL: DELAY: Call delay subroutineMVI A, 24HOUT (80H) PA: Send data on port A to glow G1 and G2MVI A, 09HOUT (81H) PB: Send data on port B to glow R3 and R4MVI C, 28H: Load multiplier count (40ıο) for delayCALL DELAY: Call delay subroutineMVI A, 12HOUT PA: Send data on port A to glow Y1 and Y2OUT PB: Send data on port B to glow Y3 and Y4MVI C, 0AH: Load multiplier count (10ıο) for delayCALL DELAY: Call delay subroutineJMP STARTDelay Subroutine:DELAY: LXI D, Count: Load count to give 0.5 sec delayBACK: DCX D: Decrement counterMOV A, DORA E: Check whether count is 0JNZ BACK: If not zero, repeatDCR C: Check if multiplier zero, otherwise repeatJNZ DELAYRET: Return to main programReferenceswww.rbainnovations.com/.../A%208085/H%20Traffic%20light%20controller-n.docwww.freshpatents.com/-dt20090702ptan20090167561.php -programs-for-8085-microprocessor.aspx -Light-Control.aspxU.S.Shah, Microprocessor and its applications, Tech- Max Pulications, Pune. Share this:FacebookFacebook logoTwitterTwitter logoRedditReddit logoLinkedInLinkedIn logoWhatsAppWhatsApp logo Cite This WorkTo export a reference to this article please select a referencing stye below:
Transparent mode takes the most time to transfer a block of data, yet it is also the most efficient mode in terms of overall system performance. In transparent mode, the DMA controller transfers data only when the CPU is performing operations that do not use the system buses. The primary advantage of transparent mode is that the CPU never stops executing its programs and the DMA transfer is free in terms of time, while the disadvantage is that the hardware needs to determine when the CPU is not using the system buses, which can be complex. This is also called "Hidden DMA data transfer mode".
As an example of DMA engine incorporated in a general-purpose CPU, some Intel Xeon chipsets include a DMA engine called I/O Acceleration Technology (I/OAT), which can offload memory copying from the main CPU, freeing it to do other work.[7] In 2006, Intel's Linux kernel developer Andrew Grover performed benchmarks using I/OAT to offload network traffic copies and found no more than 10% improvement in CPU utilization with receiving workloads.[8]
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