Engineers Garage

Controlling a Desktop Computer with a Remote Control

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Here is the project of controlling a desktop computer with a remote control. The functions of a computer like opening and closing folders, opening media player and doing its operations, etc can be done from a distance. It requires a few hardware components to build. The project is to be interfaced with the desktop computer through the computer’s keyboard port. It has a provision to connect a PS/2 keyboard to make it work simultaneously with the remote control. 

FM Module

 

 

FM Module

 
COMPONENTS:
1.         AT89S52 MICROCONTROLLER
2.         TSOP1738 INFRARED RECEIVER
3.         5 VOLT RELAY SWITCH
4.         PS/2 SOCKET
5.         ALPHANUMERIC LCD SCREEN
6.         CAPACITORS (10Uf [1], 47uF[1],33pF[2])
7.         RESISTORS (10K[2],100[1])
8.         TRANSISTOR (2N2222 [1])
9.         DIODE (1N4007[1])
10.       11.0592 MHz CRYSTAL
11.       LED
12.       SAMSUNG REMOTE
 

 Working

WORKING:
To describe the working of this project, first let us have a small discussion on the working principle of a PS/2 keyboard. The PS/2 keyboard has also a small microcontroller inside it. As soon as a key is pressed on the keyboard, the microcontroller scans it and then generates a code corresponding to the pressed key. The code is known as SCAN CODE for that particular key. The scan code is then send to the computer through the PS/2 port. The computer has a keyboard controller on its motherboard. The keyboard controller detects the SCAN CODE and accordingly does the required action. For instance if the windows logo key is pressed, the keyboard controller detects the SCAN CODE send by the keyboard and then activates the START button of the screen.
 
Likewise, in this project as a button is pressed in the remote control, it is detected and decoded by the microcontroller and then the appropriate SCAN CODE assigned to that specific button of the remote control, is generated and sends to the computer. The computer detects it as if a signal coming from an original keyboard and does the action required.
 
POWER SUPPLY AND CONNECTIONS:
The power supply needed for the assembly is taken out from the PS/2 port. So no external power supply is needed for the operation of the circuit. The connections are done as per the circuit diagram. The PS/2 plug of a PS/2 keyboard should be connected to the PS/2 socket in the project.
 PS2 Pins
Computer Back
 
REMOTE CONTROL:
Here I have used a Samsung DVD Player remote control. The model number is AH5900020E. The picture of the remote control is attached. Any remote control can be used with changes in the program. Remote
 

Operation

OPERATION:
If all the circuit connections are done correctly and the programming is done with the given program and the PS/2 plug coming out of the project is connected to the computer’s keyboard port and the PS/2 plug of a keyboard is connected to the PS/2 socket provided in the project then when the computer is switched on, the LCD screen will display ‘PASSWORD’. After you type the right password with the remote control, it will display PASSWORD GRANTED and the LED will glow and the device enters working mode and it is ready to use. If any wrong password is fed, it will display PASSWORD DENIED and will not enter to working mode. The password I have set is a four digit number i.e. ‘3’ ‘4’ ‘5’ ‘6’ of the specified remote control.
 
Also, the button ‘1’ is used as a SELECT button between two modes_ MUSIC MODE and GENERAL MODE. The working difference between the two mode is that while pressing the button ‘1’, if the device enters GENERAL MODE then lower four buttons will act as the ARROW keys of a keyboard but if the SELECT button is pressed once more then it enters MUSIC MODE and in this mode the lower four buttons will act as ‘PLAY/PAUSE’, ‘PREVIOUS’, ‘NEXT’, ‘STOP’ of the WINDOWS MEDIA PLAYER and the functions of other buttons of the remote control will remain the same.

 

 

 

 

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Project Source Code

 
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                ORG  00H                                                             ; START OF PROGRAM
 
LCD_INITIALIZATION:                                                                     ; INITIALIZING 16*2 ALPHANUMERIC LCD
                                 
                                MOV          A, #38H                                            
                                ACALL        COMNWRT
                                MOV          A, #0CH
                                ACALL        COMNWRT
                                MOV          A, #01H
                                ACALL        COMNWRT
                                MOV          A, #82H
                                ACALL        COMNWRT
 
 
 
                                IR                            EQU P1.3                             ; IR RECEIVER CONNECTED HERE
                                CMNDCOUNT    EQU R0
                                ADDRCOUNT     EQU R1
                                CMNDSTORE      EQU R2
                                ADDRSTORE       EQU R3
                                TEMPVAR                            EQU R4
                                CLK                         EQU P2                                 ; CLOCK GENERATION TO COMMUNICATE WITH PC
                                DAT                        EQU P2.2                             ; DATA GENERATION TO COMMUNICATE WITH PC
                                LED                         EQU P1.2                             ; LED IS CONNECTED HERE
                                RELAY                    EQU P2.0                             ; RELAY IS CONNECTED HERE
                                M_M                     EQU 08H
                                SELECT                  EQU 09H
 
                                
                                CLR                         M_M
                                CLR                         SELECT
                                SETB                      LED
                                MOV                     A, #0AAH                                                                              
                                ACALL                   WRITE                   
 
START:                  
                                SETB           LED       
                                SETB           00H
                                SETB           01H
                                SETB           02H
                                SETB           03H
                                SETB           04H
                                MOV        A, #01H
                                ACALL      COMNWRT
                                MOV        A, #84H
                                ACALL      COMNWRT
                                MOV        DPTR, #PASS
                                ACALL      DISPLAY
                                                                                                          
ORIGIN:                                                                                                               ; INITIALIZING IR RECEIVER
 
                                CLR          RELAY
                                MOV          A, #00                  
                                CLR          C                               
                                MOV          CMNDCOUNT, #16H    
                                MOV          ADDRCOUNT, #12       
                                MOV          TEMPVAR, #00  
                                JB           IR, $
                                ACALL        NINE 
 
GETADDR:                                                                                           ; GETTING ADDRESS FROM REMOTE CONTROL
                                JNB       IR, $           
                                ACALL     FIVESIX  
                                JNB       IR, CO  
                                ACALL     FIVESIX   
                                ACALL     FIVESIX
                                SJMP      CI           
                CO: 
                                MOV     A, TEMPVAR      
                                CLR         C                             
                                RLC         A                                             
                                MOV     TEMPVAR, A      
                                SJMP     ASTORE                                
                CI: 
                                MOV     A, TEMPVAR      
                                SETB      C                                               
                                RLC         A                                                
                                MOV     TEMPVAR, A         
                                SJMP     ASTORE                                                
                ASTORE: 
                                DJNZ      ADDRCOUNT, GETADDR               
                                MOV     A, TEMPVAR                                      
                                MOV     ADDRSTORE, A                  
                                MOV     TEMPVAR, #00                  
                
 
GETCMND:                                                                                         ; GETTING COMMAND FROM REMOTE CONTROL
                                JNB      IR, $                                            
                                ACALL    FIVESIX                                   
                                JNB      IR, SO                                      
                                ACALL    FIVESIX                                                
                                ACALL    FIVESIX                                                
                                SJMP     SI                                                                            
                SO:     
                                MOV      A, TEMPVAR                         
                                CLR      C                                                                                
                                RLC      A                                                                
                                MOV      TEMPVAR, A                      
                                SJMP     CSTORE                                                
                SI:     
                                MOV      A, TEMPVAR                      
                                SETB     C                                                               
                                RLC      A                                                                                
                                MOV      TEMPVAR, A                                      
                                SJMP     CSTORE                                                                
                CSTORE:   
                                DJNZ     CMNDCOUNT, GETCMND               
                                MOV      A, TEMPVAR                                      
                                MOV      CMNDSTORE, A                                  
 
CHECK_VALID_ADDR:                                                                    ; CHECKING FOR VALID ADDRESS OF REMOTE CONTROL
                          
                                CJNE       ADDRSTORE, #0CCH, ORIGIN         
 
 
PASSWORD_RECEPTION:                                                                             ; INITIALIZING PASSWORD RECEPTION
            
                                JNB           04H, S_CUT
                                JB            00H, FIRST
                                JB            01H, SECOND
                                JB            02H, THIRD
 
                                JB            03H, FOURTH
S_CUT:                 LJMP       DETECT_COMMAND
 
 
FIRST:   MOV       30H, CMNDSTORE                          ; RECEIVING FIRST BIT OF PASSWORD
                                CLR         00H
                                MOV       A, #0C6H
                                ACALL   COMNWRT
                                MOV       A, #'*'
                                ACALL    DATAWRT
                                SJMP       ORIGIN   
SECOND:              MOV     31H, CMNDSTORE                                            ; RECEIVING SECOND BIT OF PASSWORD
                                CLR         01H
                                MOV       A, #0C7H
                                ACALL   COMNWRT
                                MOV       A, #'*'
                                ACALL    DATAWRT
                                SJMP       ORIGIN
THIRD:                  MOV       32H, CMNDSTORE                                   ; RECEIVING THIRD BIT OF PASSWORD
                                CLR          02H
                                MOV        A, #0C8H
                                ACALL    COMNWRT
                                MOV        A, #'*'
                                ACALL    DATAWRT
                                LJMP       ORIGIN
FOURTH:                              MOV       33H, CMNDSTORE                                   ; RECEIVING FOURTH BIT OF PASSWORD
                                CLR         03H
                                MOV        A, #0C9H
                                ACALL    COMNWRT
                                MOV        A, #'*'
                                ACALL    DATAWRT
 
 
PASSWORD_AUTHENTICATION:                                                                               ; CHECKING FOR VALID PASSWORD
                                MOV          A, #01H
                                ACALL      COMNWRT
                                MOV          A, #80H
                                ACALL      COMNWRT
                                MOV          DPTR, #AUTHEN
                                ACALL      DISPLAY
                                ACALL      DELAY                 
                                MOV         A, #0EDH   
                                CJNE         A, 30H, EXIT
                                MOV         A, #0F1H   
                                CJNE         A, 31H, EXIT
                                MOV        A, #0E3H   
                                CJNE         A, 32H, EXIT
                                MOV         A, #0FDH   
                                CJNE         A, 33H, EXIT
                                SJMP         PASSWORD_GRANTED
 EXIT:                                                                                                                     ;REJECTING WRONG PASSWORD
                                MOV         A, #01H
                                ACALL     COMNWRT
                                MOV         A, #80H
                                ACALL     COMNWRT
                           MOV        DPTR, #DENIED
                                ACALL     DISPLAY
                                ACALL     DELAY  
                                LJMP        START
 
PASSWORD_GRANTED:                                                                                                ; ACCEPTING RIGHT PASSWORD           
                                MOV         A, #01H
                                ACALL     COMNWRT
                                MOV         A, #80H
                                ACALL     COMNWRT
                                MOV         DPTR, #GRANTED
                                ACALL     DISPLAY
                                ACALL     DELAY
                                CLR           04H 
                                CLR           LED
                                MOV         A, #01H
                                ACALL     COMNWRT
                                LJMP        ORIGIN
 
DETECT_COMMAND:                                                                                     ; DETECTING COMMAND FROM REMOTE CONTROL
        
CMD1:                  CJNE         CMNDSTORE, #0FFH, CMD2                     ; COMMAND_1---> MUTE            
                                MOV         A, #01H
                                ACALL     COMNWRT
                                MOV        A, #80H
                                ACALL     COMNWRT
                                MOV         DPTR, #DIS1
                                ACALL     DISPLAY
                                SETB         RELAY
                                ACALL     NINE
                                MOV        A,#0E0H                            
                                ACALL    WRITE                  
                                MOV        A, #23H                              
                                ACALL    WRITE                    
                                MOV        A, #0E0H                           
                                ACALL    WRITE                  
                                MOV        A, #0F0H                           
                                ACALL    WRITE                  
                                MOV       A, #23H                               
                                ACALL    WRITE                  
                                LJMP        ORIGIN                                
 
CMD2:                  CJNE         CMNDSTORE, #0EEH, CMD3                ; COMMAND_2---> SELECT                 
                                MOV         A, #01H
                                ACALL     COMNWRT
                                MOV         A, #80H
                                ACALL      COMNWRT
                                JB         SELECT, NCMD2
                                MOV         DPTR, #DIS2A
                                ACALL      DISPLAY
                                SETB          SELECT
                                CLR           LED
                                LJMP         ORIGIN
                                NCMD2:
                                MOV         DPTR, #DIS2B
                                ACALL      DISPLAY
                                CLR           SELECT
                                SETB          LED
                                LJMP         ORIGIN                               
CMD3:                  CJNE          CMNDSTORE, #0FEH, CMD4                ; COMMAND_3---> WIN_LOGO
                                MOV         A, #01H
                                ACALL      COMNWRT
                                MOV         A, #80H
                                ACALL      COMNWRT
                                MOV         DPTR, #DIS3
                                ACALL      DISPLAY
                                SETB         RELAY
                                ACALL     NINE
                                MOV         A, #0E0H
                                ACALL     WRITE
                                MOV         A, #1FH
                                ACALL     WRITE
                                MOV         A, #0E0H
                                ACALL     WRITE
                                MOV         A, #0F0H
                                ACALL      WRITE
                                MOV         A, #1FH
                                ACALL      WRITE
                                LJMP        ORIGIN
 
CMD4:                  CJNE         CMNDSTORE, #0EDH, CMD5               ; COMMAND_4---> SYSTEM MENU
                                MOV         A, #01H
                                ACALL     COMNWRT
                                MOV         A, #80H
                                ACALL     COMNWRT
                                MOV         DPTR, #DIS4
                                ACALL     DISPLAY              
                                SETB         RELAY
                                ACALL     NINE                    
                                MOV        A, #11H
                                ACALL     WRITE
                                MOV         A, #29H
                                ACALL     WRITE
                                MOV         A, #0F0H
                                ACALL     WRITE
                                MOV         A, #29H
                                ACALL     WRITE
                                MOV         A, #0F0H
                                ACALL      WRITE
                                MOV         A, #11H
                                ACALL      WRITE
                                LJMP         ORIGIN
 
CMD5:                  CJNE          CMNDSTORE, #0F1H, CMD6                ; COMMAND_5---> SWITCH PROGRAM
                                MOV          A, #01H
                                ACALL      COMNWRT
                                MOV          A, #80H
                                ACALL      COMNWRT                      
                                MOV          DPTR, #DIS5
                                ACALL      DISPLAY                             
                                SETB          RELAY
                                ACALL       NINE                  
                                MOV          A, #11H
                                ACALL      WRITE
                                MOV          A, #76H
                                ACALL      WRITE
                                MOV          A, #0F0H
                                ACALL      WRITE
                                MOV          A, #76H
                                ACALL      WRITE
                                MOV          A, #0F0H
                                ACALL       WRITE
                                MOV          A, #11H
                                ACALL       WRITE
                                LJMP          ORIGIN
 
CMD6:                  CJNE           CMNDSTORE, #0E3H, CMD7               ; COMMAND_6---> EXIT
                                MOV         A, #01H
                                ACALL     COMNWRT
                                MOV         A, #80H
                                ACALL      COMNWRT                      
                                MOV          DPTR, #DIS6
                                ACALL      DISPLAY                             
                                SETB          RELAY
                                ACALL      NINE                   
                                MOV         A, #11H
                                ACALL      WRITE
                                MOV          A, #0Ch
                                ACALL      WRITE
                                MOV          A, #0F0H
                                ACALL       WRITE
                                MOV          A, #0CH
                                ACALL       WRITE
                                MOV          A, #0F0H
                                ACALL       WRITE
                                MOV          A, #11H
                                ACALL       WRITE
                                LJMP          ORIGIN
 
CMD7:                  CJNE          CMNDSTORE, #0FDH, CMD8               ; COMMAND_7---> TAB
                                MOV          A, #01H
                                ACALL       COMNWRT
                                MOV          A, #80H
                                ACALL       COMNWRT                     
                                MOV          DPTR, #DIS7
                                ACALL      DISPLAY                             
                                SETB          RELAY
                                ACALL      NINE   
                                MOV          A, #0DH
                                ACALL      WRITE                                                                                                
                                MOV         A, #0F0H
                                ACALL      WRITE
                                MOV         A,#0DH
                                ACALL      WRITE
                                LJMP          ORIGIN
 
CMD8:                  CJNE           CMNDSTORE, #0F9H, CMD9              ; COMMAND_8---> FOLDER_BACK
                                MOV          A, #01H
                                ACALL       COMNWRT
                                MOV          A, #80H
                                ACALL       COMNWRT                     
                                MOV          DPTR, #DIS8
                                ACALL       DISPLAY            
                                SETB           RELAY
                                ACALL       NINE
                                MOV          A, #11h
                                ACALL      WRITE
                                MOV          A, #0E0H
                                ACALL       WRITE
                                MOV          A, #6BH
                                ACALL       WRITE
                                MOV          A, #0E0h
                                ACALL       WRITE
                                MOV          A, #0F0H
                                ACALL       WRITE
                                MOV          A, #6BH
                                ACALL       WRITE
                                MOV          A, #0F0H
                                ACALL       WRITE
                                MOV           A, #11H
                                ACALL       WRITE
                                LJMP          ORIGIN
                
CMD9:                  CJNE           CMNDSTORE, #0FAH, CMD1             ; COMMAND_9---> REFRESH
                                MOV          A, #01H
                                ACALL       COMNWRT
                                MOV          A, #80H
                                ACALL       COMNWRT                     
                                MOV          DPTR, #DIS9
                                ACALL       DISPLAY                            
                                SETB           RELAY
                                ACALL       NINE                  
                                MOV          A, #03H
                                ACALL       WRITE
                                MOV          A, #0F0h
                                ACALL       WRITE
                                MOV          A, #03H
                                ACALL       WRITE
                                LJMP          ORIGIN
 
CMD10:                                CJNE           CMNDSTORE, #0E9H, CMD11            ; COMMAND_10---> ESCAPE 
                                MOV          A, #01H
                                ACALL       COMNWRT
                                MOV          A, #80H
                                ACALL       COMNWRT     
                                MOV          DPTR, #DIS10
                                ACALL      DISPLAY                             
                                SETB          RELAY
                                ACALL      NINE                   
                                MOV          A, #76h
                                ACALL       WRITE
                                MOV          A, #0F0H
                                ACALL      WRITE
                                MOV          A, #76H
                                ACALL      WRITE
                                LJMP          ORIGIN
 
CMD11:                                CJNE           CMNDSTORE, #0F5H, CMD12            ; COMMAND_11---> FOLDER_FORWARD
                                MOV           A, #01H
                                ACALL       COMNWRT
                                MOV           A, #80H
                                ACALL       COMNWRT                     
                                MOV          DPTR, #DIS11
                                ACALL       DISPLAY            
                                SETB           RELAY
                                ACALL       NINE                  
                                MOV          A, #11h
                                ACALL      WRITE
                                MOV          A, #0E0H
                                ACALL      WRITE
                                MOV          A, #74H
                                ACALL      WRITE
                                MOV          A, #0E0h
                                ACALL      WRITE
                                MOV          A, #0F0H
                                ACALL       WRITE
                                MOV          A, #74H
                                ACALL       WRITE
                                MOV          A,#0F0H
                                ACALL       WRITE
                                MOV          A,#11H
                                ACALL       WRITE
                                LJMP          ORIGIN
                
CMD12:                                CJNE           CMNDSTORE, #0FBH, CMD13           ; COMMAND_12---> MINIMIZE, MAXIMIZE
                                MOV          A, #01H
                                ACALL       COMNWRT
                                MOV          A, #80H
                                ACALL       COMNWRT                     
                                JB                M_M, MINI
                                SETB           M_M                                
                                MOV           DPTR, #DIS12A
                                ACALL        DISPLAY
                                SETB           RELAY
                                ACALL       NINE                  
                                MOV           A, #0E0H
                                ACALL        WRITE
                                MOV           A, #1FH
                                ACALL        WRITE
                                MOV           A, #12h
                                ACALL        WRITE
                                MOV           A, #3AH
                                ACALL        WRITE
                                MOV           A, #0F0H
                                ACALL        WRITE
                                MOV           A, #3AH
                                ACALL        WRITE
                                MOV           A, #0F0H
                                ACALL        WRITE
                                MOV           A, #12H
                                ACALL        WRITE
                                MOV           A, #0E0h
                                ACALL        WRITE
                                MOV           A, #0F0H
                                ACALL        WRITE
                                MOV           A, #1FH
                                ACALL        WRITE
                                LJMP           ORIGIN
                                MINI:
                                CLR             M_M
                                MOV           DPTR,#DIS12B
                                ACALL        DISPLAY                           
                                SETB            RELAY
                                ACALL        NINE                 
                                MOV           A, #0E0H
                                ACALL        WRITE
                                MOV           A, #1FH
                                ACALL        WRITE
                                MOV           A, #3AH
                                ACALL        WRITE
                                MOV           A, #0F0H
                                ACALL        WRITE
                                MOV           A, #3AH
                                ACALL        WRITE
                                MOV           A, #0E0h
                                ACALL        WRITE
                                MOV           A, #0F0H
                                ACALL        WRITE
                                MOV           A, #1FH
                                ACALL        WRITE
                                LJMP          ORIGIN
 
CMD13:                                CJNE           CMNDSTORE, #0EFH, CMD1            ; COMMAND_13---> ALTER
                                MOV           A, #01H
                                ACALL        COMNWRT
                                MOV           A, #80H
                                ACALL        COMNWRT                    
                                MOV           DPTR, #DIS13
                                ACALL        DISPLAY
                                SETB            RELAY
                                ACALL        NINE                 
                                MOV           A, #11h
                                ACALL       WRITE
                                MOV           A, #0F0H
                                ACALL       WRITE
                                MOV           A, #11H
                                ACALL       WRITE
                                LJMP          ORIGIN
 
CMD14:                                CJNE           CMNDSTORE, #0E4H, CMD1            ; COMMAND_14---> APPS
                                MOV          A, #01H
                                ACALL       COMNWRT
                                MOV          A, #80H
                                ACALL       COMNWRT                     
                                MOV          DPTR, #DIS14
                                ACALL       DISPLAY                            
                                SETB          RELAY
                                ACALL      NINE                   
                                MOV         A, #0E0h
                                ACALL     WRITE
                                MOV         A, #2FH
                                ACALL     WRITE
                                MOV         A, #0E0H
                                ACALL     WRITE
                                MOV         A, #0F0H
                                ACALL     WRITE
                                MOV         A, #2FH
                                ACALL     WRITE
                                LJMP        ORIGIN
 
CMD15:                                CJNE         CMNDSTORE, #0EAH, CMD16             ; COMMAND_15---> FUNCTION4
                                MOV         A, #01H
                                ACALL     COMNWRT
                                MOV         A, #80H
                                ACALL     COMNWRT                       
                                MOV         DPTR, #DIS15
                                ACALL     DISPLAY                              
                                SETB         RELAY
                                ACALL     NINE                    
                                MOV         A, #0Ch
                                ACALL     WRITE
                                MOV         A, #0F0H
                                ACALL     WRITE
                                MOV         A, #0CH
                                ACALL     WRITE
                                LJMP        ORIGIN
                
CMD16:                                CJNE         CMNDSTORE, #0F7H, CMD17              ; COMMAND_16---> VOLUME DOWN
                                MOV        A, #01H
                                ACALL     COMNWRT
                                MOV        A, #80H
                                ACALL       COMNWRT
                                MOV           DPTR, #DIS16
                                ACALL        DISPLAY                           
                                JB                 SELECT, NCMD16                        
                                SETB            RELAY
                                ACALL        NINE                 
                                MOV           A, #0E0H
                                ACALL        WRITE
                                MOV           A, #21H
                                ACALL        WRITE
                                MOV           A, #0E0H
                                ACALL        WRITE
                                MOV           A, #0F0H
                                ACALL        WRITE
                                MOV           A, #21H
                                ACALL         WRITE
                                LJMP           ORIGIN
                                NCMD16:
                                SETB            RELAY
                                ACALL        NINE                 
                                MOV           A, #01H
                                ACALL        WRITE
                                MOV           A, #0F0H
                                ACALL         WRITE
                                MOV           A, #01H
                                ACALL         WRITE
                                LJMP            ORIGIN
 
CMD17:                                CJNE             CMNDSTORE, #0E7H, CMD1           ; COMMAND_17---> VOLUME UP
                                MOV             A,#01H
                                ACALL         COMNWRT
                                MOV             A,#80H
                                ACALL         COMNWRT
                                MOV            DPTR,#DIS17
                                ACALL          DISPLAY                         
                                JB                   SELECT, NCMD17                                                      
                                SETB             RELAY
                                ACALL          NINE                               
                                MOV             A, #0E0H
                                ACALL          WRITE
                                MOV             A, #32H
                                ACALL         WRITE
                                MOV            A, #0E0H
                                ACALL         WRITE
                                MOV            A, #0F0H
                                ACALL         WRITE
                                MOV            A, #32H
                                ACALL         WRITE
                                LJMP            ORIGIN
                                NCMD17:
                                SETB             RELAY
                                ACALL         NINE                                
                                MOV             A, #09H
                                ACALL         WRITE
                                MOV             A, #0F0H
                                ACALL         WRITE
                                MOV             A, #09H
                                ACALL         WRITE
                                LJMP            ORIGIN
 
CMD18:                                CJNE             CMNDSTORE, #0F4H, CMD19          ; COMMAND_18---> ARR0W UP, PLAY/PAUSE 
                                MOV           A, #01H
                                ACALL        COMNWRT
                                MOV           A, #80H
                                ACALL        COMNWRT                    
                                JB                 SELECT, NCMD18                        
                                MOV           DPTR, #DIS18A
                                ACALL        DISPLAY                           
                                SETB            RELAY
                                ACALL        NINE                 
                                MOV           A, #0E0H
                                ACALL        WRITE
                                MOV           A, #75h
                                ACALL        WRITE
                                MOV           A, #0E0H
                                ACALL        WRITE
                                MOV           A, #0F0H
                                ACALL        WRITE
                                MOV           A, #75H
                                ACALL        WRITE
                                LJMP          ORIGIN
                                NCMD18:
                                MOV          DPTR,#DIS18B
                                ACALL       DISPLAY                            
                                SETB           RELAY
                                ACALL       NINE                  
                                MOV          A, #0E0H
                                ACALL       WRITE
                                MOV          A, #34H
                                ACALL       WRITE
                                MOV          A, #0E0H
                                ACALL       WRITE
                                MOV          A, #0F0H
                                ACALL       WRITE
                                MOV          A, #34H
                                ACALL       WRITE
                                LJMP          ORIGIN
 
CMD19:                                CJNE          CMNDSTORE, #0F2H, CMD20           ; COMMAND_19---> ARROW LEFT, PREVIOUS           
                                MOV          A, #01H
                                ACALL       COMNWRT
                                MOV          A, #80H
                                ACALL       COMNWRT                     
                                JB                SELECT, NCMD19                         
                                MOV           DPTR,#DIS19A
                                ACALL        DISPLAY                           
                                SETB            RELAY
                                ACALL        NINE 
                                MOV           A, #0E0H
                                ACALL        WRITE
                                MOV           A, #6Bh
                                ACALL        WRITE
                                MOV           A, #0E0H
                                ACALL        WRITE
                                MOV           A, #0F0H
                                ACALL        WRITE
                                MOV           A, #6BH
                                ACALL        WRITE              
                                LJMP           ORIGIN
                                NCMD19:
                                MOV           DPTR, # DIS19B
                                ACALL        DISPLAY                           
                                SETB            RELAY
                                ACALL        NINE                 
                                MOV            A, #0E0H
                                ACALL       WRITE
                                MOV           A, #15H
                                ACALL        WRITE
                                MOV           A, #0E0H
                                ACALL        WRITE
                                MOV            A, #0F0H
                                ACALL        WRITE
                                MOV            A, #15H
                                ACALL        WRITE
                                LJMP           ORIGIN
 
CMD20:                                CJNE           CMNDSTORE, #0E1H, CMD21         ; COMMAND_20---> ENTER
                                MOV           A, #01H
                                ACALL        COMNWRT
                                MOV            A, #80H
                                ACALL        COMNWRT                    
                                MOV            DPTR, #DIS20
                                ACALL         DISPLAY                          
                                SETB            RELAY
                                ACALL         NINE                                
                                MOV            A, #5AH
                                ACALL         WRITE
                                MOV            A, #0F0H
                                ACALL         WRITE
                                MOV            A, #5AH
                                ACALL         WRITE
                                LJMP            ORIGIN
 
CMD21:                                CJNE             CMNDSTORE, #0E2H, CMD22         ; COMMAND_21---> ARROW RIGHT, NEXT 
                                MOV             A, #01H
                                ACALL          COMNWRT
                                MOV             A, #80H
                                ACALL         COMNWRT
                                JB                  SELECT, NCMD21                       
                                MOV             DPTR, #DIS21A
                                ACALL          DISPLAY                         
                                SETB              RELAY
                                ACALL          NINE
                                MOV             A, #0E0H
                                ACALL          WRITE
                                MOV             A, #74h
                                ACALL          WRITE
                                MOV             A, #0E0H
                                ACALL          WRITE
                                MOV             A, #0F0H
                                ACALL          WRITE
                                MOV             A, #74H
                                ACALL           WRITE
                                LJMP              ORIGIN
                                NCMD21:
                                MOV              DPTR, #DIS21B
                                ACALL           DISPLAY                        
                                SETB               RELAY
                                ACALL           NINE              
                                MOV              A, #0E0H
                                ACALL           WRITE
                                MOV              A, #4DH
                                ACALL           WRITE
                                MOV             A, #0E0H
                                ACALL         WRITE
                                MOV             A, #0F0H
                                ACALL         WRITE
                                MOV             A, #4DH
                                ACALL         WRITE
                                LJMP            ORIGIN
 
CMD22:                                CJNE             CMNDSTORE, #0ECH, ORI             ; COMMAND_22---> ARROW DOWN, STOP
                                MOV            A, #01H
                                ACALL        COMNWRT
                                MOV           A,#80H
                                ACALL        COMNWRT                    
                                JB                 SELECT, NCMD22        
                                MOV            DPTR, #DIS22A
                                ACALL        DISPLAY                           
                                SETB            RELAY
                                ACALL        NINE                 
                                MOV           A, #0E0H
                                ACALL       WRITE
                                MOV           A, #72h
                                ACALL       WRITE
                                MOV           A, #0E0H
                                ACALL       WRITE
                                MOV           A, #0F0H
                                ACALL       WRITE
                                MOV          A, #72H
                                ACALL       WRITE
                                LJMP         ORIGIN
                                NCMD22:
                                MOV         DPTR, #DIS22B
                                ACALL      DISPLAY             
                                SETB          RELAY
                                ACALL       NINE                  
                                MOV          A, #0E0H
                                ACALL      WRITE
                                MOV          A, #3BH
                                ACALL      WRITE
                                MOV          A, #0E0H
                                ACALL      WRITE
                                MOV          A, #0F0H
                                ACALL      WRITE
                                MOV          A, #3BH
                                ACALL      WRITE
ORI:                       LJMP         ORIGIN                                                        ; END OF DETECTING COMMAND
 
 
WRITE:                                                                                                  ; SUBROUTINE FOR SENDING SIGNAL TO PC
                                MOV          C, PSW.0                                                                                                         
                                MOV           07H, C                                                
                                CHK:
                                JNB             CLK, $                                                 
                                MOV          R7, #27                                               
                                DJNZ          R7, $                                    
                                JNB             CLK, CHK                                         
                                CLR         DAT                                                       
                                ACALL      FIVE                                    
                                CLR           CLK                                                        
                                ACALL      FREQUENCY                     
                                SETB         CLK                                        
                                ACALL      FREQUENCY                      
                                MOV          R0,#08H                                             
                                AGAIN:
                                RRC            A                                                                         
                                MOV          DAT,C                                               
                                ACALL       FIVE                                   
                                CLR            CLK                                                                     
                                ACALL       FREQUENCY                      
                                SETB          CLK                                       
                                ACALL       FREQUENCY                    
                                DJNZ          R0, AGAIN                         
                                MOV          C, 07H                                                 
                                CPL            C                                                            
                                MOV          DAT, C                                                 
                                ACALL      FIVE                                      
                                CLR            CLK                                                       
                                ACALL      FREQUENCY                       
                                SETB          CLK                                        
                                ACALL      FREQUENCY                       
                                SETB          C                                                             
                                MOV         DAT, C                                                  
                                ACALL      FIVE                                      
                                CLR           CLK                                                        
                                ACALL      FREQUENCY                       
                                SETB         CLK                                      
                                ACALL      FREQUENCY                       
                                RET                                                                            
 
COMNWRT:                                                                                   ; SUBROUTINE FOR SENDING COMMAND TO LCD
                                MOV          P3, A
                                CLR            P1.0
                                SETB          P1.1
                                ACALL      NINE
                                CLR           P1.1
                                RET
 
DATAWRT:                                                                                      ; SUBROUTINE FOR SENDING DATA TO LCD
                                MOV         P3, A
                                SETB         P1.0
                                SETB         P1.1
                                ACALL     NINE 
                                CLR          P1.1
                                RET
 
FIVE:                                                                                                   ; SUBROUTINE FOR 5 MICROSECOND DELAY
                                MOV        R7, #3    
                                DJNZ        R7, $      
                                RET                                           
 
FREQUENCY:                                                                                    ; SUBROUTINE FOR FREQUENCY GENERATION
                                MOV         R7, #17                                                              TO COMMUNICATE WITH PC
                                FG:
                                DJNZ         R7, FG                   
                                RET                                                           
 
FIVESIX:                                                                                             ; SUBROUTINE FOR 0.55 MILLISECOND DELAY
                                MOV         R7, #255           
                                DJNZ         R7, $      
                                MOV          R7, #24               
                                DJNZ         R7, $   
                                RET                                                         
 
NINE:    
                                MOV         R5, #16                                                          ; SUBROUTINE FOR 9 MILLISECOND DELAY
                                NINAG:
                                MOV          R6, #250          
                                DJNZ          R6, $                  
                                DJNZ          R5, NINAG      
                                RET                                                         
 
DISPLAY:                                                                                           ; SUBROUTINE FOR DISPLAYING DATA ON LCD
                                BK:
                                CLR             A
                                MOVC        A,@A+DPTR
                                JZ                OUT
                                ACALL       DATAWRT
                                INC             DPTR
                                SJMP          BK
                                OUT:            RET
 
DELAY:                  MOV          R5, #20                                                           ; SUBROUTINE FOR 3 SECOND DELAY
    RT:                      MOV          R6, #255
    RE:                      MOV          R7, #255
                                DJNZ          R7, $
                                DJNZ          R6, RE
                                DJNZ          R5, RT
                                RET 
 
STRING:                                                                                                                               ; TABLE FOR STRING
 
PASS:                    DB 'PASSWORD', 0
AUTHEN:             DB 'AUTHENTICATING..', 0
DENIED:               DB 'PASSWORD DENIED', 0
GRANTED:                           DB 'PASSWORD GRANTED', 0
DIS22A:                DB 'ARROW DOWN', 0
DIS22B:                 DB 'STOP', 0
DIS21A:                DB 'ARROW RIGHT', 0
DIS21B:                 DB 'NEXT', 0
DIS20:                   DB 'ENTER ', 0
DIS19A:                DB 'ARROW LEFT', 0
DIS19B:                 DB 'PREVIOUS', 0
DIS18A:                DB 'ARROW UP', 0
DIS18B:                 DB 'PLAY/PAUSE', 0
DIS17:                   DB 'INCREASE VOLUME', 0
DIS16:                   DB 'DECREASE VOLUME', 0
DIS15:                   DB 'ADDRESS BAR', 0
DIS14:                   DB 'APPS', 0
DIS13:                   DB 'MENU BAR', 0
DIS12A:                DB 'MAXIMIZE', 0
DIS12B:                 DB 'MINIMIZE', 0              
DIS11:                   DB 'FOLDER FORWARD', 0
DIS10:                   DB 'ESCAPE', 0
DIS9:                      DB 'REFRESH', 0
DIS8:                      DB 'FOLDER BACKWARD', 0
DIS7:                      DB 'TAB', 0
DIS6:                      DB 'QUIT', 0        
DIS5:                      DB 'SWITCH PROGRAM', 0
DIS4:                      DB 'SYSTEM MENU', 0
DIS3:                      DB 'START', 0
DIS2A:                   DB 'MUSIC MODE', 0
DIS2B:                   DB 'GENERAL MODE', 0
DIS1:                      DB 'MUTE', 0
                                                                                                                END OF PROGRAM 
 
 
 
###
 

Circuit Diagrams

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