Rotate Instructions in 8085 Microprocessor to Support Traffic control Signal Processes through Assembly Language which to be Taken as Input of 05H

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1 Rotate Instructions in 8085 Microprocessor to Support Traffic control Signal Processes through Assembly Language which to be Taken as Input of 05H P.Hariharan 1, Assistant Professor Department of Computer Science & Application, Adhiparasakthi college of Arts & Science G.B.Nagar,Kalavai, , Vellore District Tamilnadu, India, ABSTRACT Dr.G.Arutchelvan 2, Director & Head Department of Computer Science & Application, Adhiparasakthi college of Arts & Science G.B.Nagar, Kalavai, , Vellore District Tamilnadu, India In this paper an exact solution has been obtained for traffic signal Processes. These design have been constructed by taken as input of 05H and use rotate instruction in 8085 microprocessor. The concept explaining step by step through assembly language involving 8085 instruction set. The various timings used for different signals will also be discussed. This method of concepts can be use for the development in the field of microprocessor. Keywords: Green, Yellow, Red. Walk, Don t Walk INTRODUCTION This is the simplest way for controlling the traffic signal processes. The solution has been obtained by step by step through assembly language involving 8085 instruction set. The method of process can provide on/off time to three traffic lights (Green, Yellow and Red and two pedestrian sign (Walk and Don t Walk). The lights and sign are turned on /off by the data bits (05H. and RLC & RRC instruction). The Various timings used for different lights signals can be controlled by subroutine. Various timings for signal is passed between a calling program and a subroutine also may be used by calling program. PROBLEM STATEMENT The following assembly language program to given on/off time to three traffic lights (Yellow, green and Red) and two pedestrian signs (Walk and Don t Walk). The lights and signs are turned on/off by the data bits of an output port as shown below, Lights Bits Signal time Yellow D5 5 Seconds Green D0 25 seconds Red D1 30 seconds Walk D2 25 seconds Don t Walk D3 30/5 Seconds The Signal of traffic and Pedestrian flow are in the same direction, The pedestrian should cross road when the green light is on. PROBLEM ANALYSIS The requirement of the problem is primarily concerned to Rotate (RLC & RRC) instruction in 8085 Microprocessor with providing various time delays for complete sequences of 60 seconds, the on/off times for the traffic signals and pedestrian sign are as follows 17 P a g e

2 The Green light and the Walk sign can be turned on by sending data byte of 05H to the Output port. The delay of 25 seconds can be provided by using 1 second subroutine and a counter with a count of 25. Next the instruction RLC and RRC can be used to turn on/off of the appropriate lights / Signs as shown in the following flowchart. The required time delays are provided by changing the values of the count in the counter. 18 P a g e

3 ASSEMBLY LANGUAGE PROGRAM WITH ROTATE INSTRUCTIONS Memory Code Label Mnemonics Comments Address XX00 31 Initialize Stack Pointer address of location XX98H XX01 98 LXI SP XX98 XX02 XX Higher order address page of user memory XX03 3E XX04 05 XX05 C3 XX06 07 XX07 XX08 19 P a g e D3 Port# XX09 06 XX0A 25 Start MVI A 05H JMP Green Outport# MVI B, 25H Load the Bit accumulator Bit Pattern for Walk and Green Jump the location of XX07 for light on (Walk and Green) Turn on green light and Walk Use B as counter to count 25 seconds by Subroutine XX0B CD CALL DELAY Call delay subroutine located At XX50H XX0C 50 XX0D XX Higher order address page of user memory XX0E C3 Jump the location of XX10 for JMP Yellow XX0F 10 light on (Yellow and Walkout) XX10 07 RLC Accumulator Rotate left with Carry XX11 07 RLC Accumulator Rotate left with Carry XX12 07 RLC Accumulator Rotate left with Carry XX13 D3 Outport# Turn on Yellow light and Walk out

4 XX14 Port# XX15 06 MVI B, 05H Set up 5 Seconds Delay Counter XX16 05 XX17 CD CALL DELAY Call delay subroutine located at XX50H XX18 50 XX19 XX Higher order address page of user memory XX1A C3 JMP Green Jump the location of XX07 for light on (Walk and Green) XX1B 1C XX1C 0F RRC Accumulator Rotate Right with Carry XX1D 0F RRC Accumulator Rotate Right with Carry XX1E D3 Outport# Turn on Red light and Walk out, Keep Turn off Yellow light XX1F Port# XX20 06 XX21 30 XX22 CD XX23 50 MVI B, 30H CALL DELAY Set up 30 Seconds Delay Counter Call delay subroutine located at XX50H XX24 XX Higher order address page of user memory XX25 AF XRA A Clear the Accumulator and Flag XX26 C3 XX27 03 XX28 XX JMP Start Go Back the location start to repeat the Sequences Delay Subroutine: Delay: This is a 1 Second delay subroutine that Provides delay according to the parameter register B Input : Number of Seconds is specified in Register B. Output: None Memory Code Label Mnemonics Comments Address XX50 D5 Delay PUSH D Save Contents of DE XX51 F5 PUSH PSW XX52 11 Second LXI D, Count Load Register Pair DE with a count for 1 Second delay XX53 LO XX54 HI XX55 1B Loop DCX B Decrement Register Pair DE XX56 B3 ORA E OR (D) & (E) Set Zero Flag XX57 C2 Jump to loop if delay count is not equal to 0 XX58 55 JNZ Loop XX59 XX XX5A 05 DCR B End of 1 Second Delay; Decrement the Counter XX5B C2 JNZ Second Is this the end of time needed? If not go back to repeat XX5C 52 1 Second delay XX5D XX Higher order address page of user memory XX5E F1 POP PSW Retrieve Contents of Saved Registers XX5F D1 POP D XX60 C9 RET Return to Main Program PROBLEM DESCRIPTION The Stack Pointer register is initialized at XX99H so that return address can be stored on the stack whenever CALL Instructions is used. As Shown in the flowchart this program loads the appropriate bit pattern in the accumulator sends it to the output port, and calls the delay routine. Register B is loaded the time in main program and used in the subroutine to provide appropriate timings. This Example illustrates the type of Subroutine that is called many times from various locations in the main program as illustrated in following figure-(multiple Calling Subroutine) 20 P a g e

5 CONCLUSION Its very clear with the help of pattern obtained by controlling the various lights and Signs in traffic. The three different data bits controlled the light and signs. The data bits are obtained by 05H and RLC and RRC instructions. The proper time delay for different lights and signs obtained by the subroutine delay. Various Timings for different lights and signals is passed between a calling program and a subroutine. The subroutine performs respective delay for different signals before returning from the subroutine. REFERENCES [1] Ramesh S.Gaonkar Microprocessor Architecture Programming and Applications with the th Edition penram International publishing (India) [2] Microprocessor an interfacing programming and hardware Douglas V.Hall TMH second Edition [3] Microprocessor Theory and Applications Intel and Motorala M. RafiQuzzqiman PHI Revised Edition [4] Microprocessor and Peripherals Brey CBS Publication 2 nd Edition [5] The 8088 and 8086 Microprocessor Programming Interfacing, Software Hardware and Applications Walter A.Triebel Autar Singh Prentince Hall of India [6] Microprocessor Technology and Microcomputer Edward J,Pasahow TMH [7] Introduction to Microprocessor Aditya P.Mathur 3 rd Edition TMH 21 P a g e

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