MikrocontrollerNET.asm


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  TITLE ''

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  LIST P=16F877A

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  __config H'F7BA'

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  ;******************************************************************

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  ;*                      CONSTANT DECLARATIONS                     *

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  ;******************************************************************

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TMR0  EQU 1    ;Timer 0 is register 1 (Bank 0)

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STATUS  EQU 3    ;Status register is register 3

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RP0  EQU 5    ;Bit 5 of Status (Bank Select Bit)

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PORTA  EQU 5    ;Port A is register 5 (Bank 0)   

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PORTB     EQU 6       ;Port B is register 6 (Bank 0)

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PORTC  EQU 7

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PORTD  EQU  8

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PORTE  EQU 9    ;Port E is register 9 (Bank 0)

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OPTION_REG EQU 81  ;is register 81 (Bank 1)

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TRISA  EQU 85    ;TRIS A is register 85 (Bank 1)

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TRISB  EQU 86    ;TRIS B is register 86 (Bank 1)

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TRISC  EQU 87

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TRISD  EQU  88

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TRISE  EQU 89    ;TRIS E is register 89 (Bank 1)

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ADCON0  EQU 1F    ;ADCON0 is register 1F (Bank 0) analog to digital converter

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ADCON1  EQU 9F    ;ADCON1 is register 9F (Bank 1) analog to digital converter

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ADRESH  EQU 1E    ;ADRESH is register 1E (Bank 0) storage register of result of A/D converting

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PC    EQU 2    ;PCL is register 2 (Bank 0)

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T2CON  EQU 12

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CCP1CON EQU 17

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PR2  EQU  92

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CCPR1L  EQU 15

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ADVAL  EQU 20    ;ADVAL is register 20 (Bank 0)for AD value

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HUNDR  EQU 21    ;register for value of the hundreds

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TENS  EQU 22    ;register for value of the tens

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UNITS  EQU 23    ;register for value of the units

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TRANS  EQU 24

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  ;******************************************************************

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  ;*                     RESET VECTOR DEFINITION                    *

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  ;******************************************************************

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  ORG     0x00

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  GOTO    CFIG        ;Set the reset vector

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  ORG     0x06  ;Jump over interrupt vector 

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  ;******************************************************************

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  ;*                       INITIALISATION                           *

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  ;******************************************************************

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CFIG    

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  BSF    STATUS,RP0  ;Jump to Bank 1

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  MOVLW  B'11111111'  ;Load value in W 

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  MOVWF  TRISA    ;with content of W configure all bits of PortA as input with content of W

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            ;default setting are input only for make sure

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  CLRF  TRISB    ;Configure all bits of PORTB as OUTPUT

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  CLRF  TRISC    ;Configure all bits of PORTC as OUTPUT

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  CLRF  TRISD    ;Configure all bits of PORTD as OUTPUT

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  CLRF  TRISE    ;Configure all bits of PORTE as OUTPUT

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  MOVLW  B'00000010'  ;Load value in W 

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  MOVWF  ADCON1    ;Set RE0-2 as digital OUTPUT RA0-4 as analog INPUT and VDD as Vref+ and ADRESH use

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  MOVLW  B'00000111'  ;Load value in W

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  MOVWF  OPTION_REG  ;Increment TMR0 based on internal instr. cycle clock (Bit 5), 

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            ;prescale TMR0 (Bit 3) at 256:1 (Bit 0-2)  

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  BCF    STATUS,RP0  ;Jump back to Bank 0   

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  MOVLW  0xc1

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  MOVWF  ADCON0  

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MOVLW  B'00000100'

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MOVWF  T2CON

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BSF   STATUS,RP0

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MOVLW   d'254'

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MOVWF  PR2

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BCF    STATUS,RP0

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MOVLW  d'255'

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MOVWF  CCPR1L

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CLRF  CCP1CON

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BSF  CCP1CON,3

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BSF  CCP1CON,2

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  ;******************************************************************

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  ;*                       MAIN BODY                                *

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  ;******************************************************************

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START

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  CLRF  HUNDR    ;Clear storage register of hundreds

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  CLRF  TENS    ;Clear storage register of tens

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  CLRF  UNITS    ;Clear storage register of units

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  ;MOVLW  B'11000001'  ;Load value in W 

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  ;MOVWF  ADCON0    ;set internal Clock (Bit 6,7) read RA0 (Bit 3,4,5)(and A/D-converter ON (Bit 0

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  BSF   ADCON0,2  ;Start of A/D converting

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ADLOOP_RA0

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  BTFSC  ADCON0,2  ;Test if A/D converting was succsessfull, if YES (Bit2="0")overjump next

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  GOTO   ADLOOP_RA0    ;Jump back to ADLOOP if A/D converting was not succsessfull (Bit2="1")

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  MOVF  ADRESH,W  ;MOVE Result of A/D converting from ADRESH to Working register

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  MOVWF  ADVAL    ;MOVE result from W to ADVAL register 20 (Bank 0)

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  MOVWF PORTD

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CALL DMTime

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CLRF ADRESH

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  MOVLW  B'11001001'    ;Load value in W 

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  MOVWF  ADCON0    ;set internal Clock (Bit 6,7) read RA1 (Bit 3,4,5)(and A/D-converter ON (Bit 0

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  BSF   ADCON0,2  ;Start of A/D converting

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ADLOOP_RA1

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  BTFSC  ADCON0,2  ;Test if A/D converting was succsessfull, if YES (Bit2="0")overjump next

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  GOTO   ADLOOP_RA1    ;Jump back to ADLOOP if A/D converting was not succsessfull (Bit2="1")

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  MOVF  ADRESH,W  ;MOVE Result of A/D converting from ADRESH to Working register

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  MOVWF  TRANS    ;MOVE result from W to ADVAL register 20 (Bank 0)  

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MOVF  TRANS,W

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MOVWF  CCPR1L

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CALL DMTime

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GOTO  START      ;Jump back to START for a new program cycle

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; ---- HUNDREDS CALCULATION ----

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  MOVLW  .100      ;load the decimal value 100 into W

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H_sub

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  SUBWF   ADVAL,1      ;subtract the 100 from ADVAL

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  BTFSS  STATUS,0    ;test status bit 0 (carry), if it is set the result of subtraction was pos.

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              ;then skip next instruction

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  GOTO  CALC_T

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  INCF  HUNDR,1      ;last subtraction was successful (positive) 

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              ;Hundreds value of ADVAL is bigger than 100 increase Hundreds

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  GOTO  H_sub      ;jump back to H_sub loop

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; ---- TENS CALCULATION ----

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CALC_T            

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  ADDWF  ADVAL,1      ;add 100 back to the negative result of last H_sub to get a positive value

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  MOVLW  .10        ;load the decimal value 10 into W

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T_sub

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  SUBWF   ADVAL,1      ;subtract the 10 from ADVAL

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  BTFSS  STATUS,0    ;test status bit 0 (carry), if it is set the result of subtraction was pos.

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              ;then skip next instruction

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  GOTO  CALC_U

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  INCF  TENS,1      ;last subtraction was successful (positive) 

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              ;Tens value of ADVAL is bigger than 10 increase Tens

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  GOTO  T_sub      ;jump back to T_sub loop

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; ---- UNITS CALCULATION ----

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CALC_U            

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  ADDWF  ADVAL,1      ;add 10 back to the negative result of last T_sub to get a positive value

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  MOVLW  .1        ;load the decimal value 1 into W

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U_sub

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  SUBWF   ADVAL,1      ;subtract the 1 from ADVAL

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  BTFSS  STATUS,0    ;test status bit 0 (carry), if it is set the result of subtraction was pos.

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              ;then skip next instruction

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  GOTO DISPL          ;back to MAIN PROGRAM

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  INCF  UNITS,1      ;last subtraction was successful (positive) 

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              ;Units value of ADVAL is bigger than 1 increase Tens

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  GOTO  U_sub      ;jump back to U_sub loop

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; ---- Lighting the 3 Digits of 7 Segment Display ----

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DISPL  

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  MOVF  HUNDR,0      ;Load value of hundreds into W

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  CALL  LOOKUP      ;take 7 segment code from out of the lookup table

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  MOVWF  PORTB      ;move 7 segment code to Port B

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  BSF    PORTE,2      ;Switch ON bit 2 of Port E for digit hundreds

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  CALL  DMTime      ;call multiplexing Timer and wait as long as reached setted value

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  BCF    PORTE,2      ;Switch OFF bit 2 of Port E for digit hundreds

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  MOVF  TENS,0      ;Load value of tens into W

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  CALL  LOOKUP      ;take 7 segment code from out of the lookup table

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  MOVWF  PORTB      ;move 7 segment code to Port B

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  BSF    PORTE,1      ;Switch ON bit 1 of Port E for digit tens

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  CALL  DMTime      ;call multiplexing Timer and wait as long as reached setted value

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  BCF    PORTE,1      ;Switch OFF bit 2 of Port E for digit tens

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  MOVF  UNITS,0      ;Load value of units into W

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  CALL  LOOKUP      ;take 7 segment code from out of the lookup table

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  MOVWF  PORTB      ;move 7 segment code to Port B

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  BSF    PORTE,0      ;Switch ON bit 0 of Port E for digit units

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  CALL  DMTime      ;call multiplexing Timer and wait as long as reached setted value

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  BCF    PORTE,0      ;Switch OFF bit 2 of Port E for digit units

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  ;******************************************************************

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  ;*                      Subroutines                               *

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  ;******************************************************************

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;***** LOOKUP TABLE *****

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LOOKUP

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  ADDWF  PC,1      ;add content of W to program counter

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  ;     DPgfedcba   

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  RETLW  B'00111111'    ;return with BCD-Code for 7 Segm.Display "0"

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  RETLW  B'00000110'    ;return with BCD-Code for 7 Segm.Display "1"

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  RETLW  B'01011011'    ;return with BCD-Code for 7 Segm.Display "2"

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  RETLW  B'01001111'    ;return with BCD-Code for 7 Segm.Display "3"

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  RETLW  B'01100110'    ;return with BCD-Code for 7 Segm.Display "4"

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  RETLW  B'01101101'    ;return with BCD-Code for 7 Segm.Display "5"

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  RETLW  B'01111101'    ;return with BCD-Code for 7 Segm.Display "6"

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  RETLW  B'00000111'    ;return with BCD-Code for 7 Segm.Display "7"

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  RETLW  B'01111111'    ;return with BCD-Code for 7 Segm.Display "8"

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  RETLW  B'01101111'    ;return with BCD-Code for 7 Segm.Display "9"

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;***** Display Multiplexing Time *****

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DMTime

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  MOVLW  .25        ;load the decimal value 25 into W 

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  MOVWF  TMR0      ; preadjust timer with 25 (content of W)

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DMT_Loop

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  BTFSS  TMR0,6      ;test bit 6 (dec value 64)of timer TMR0 if it is set, skip next instruction

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  GOTO  DMT_Loop    ;jump back to the Loop

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  RETURN          ;jump back to main program

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  END