;PART OF CODE:    
Main:
    movlw   .7                  ;serial data has to be shifted seven times
    movwf   shift_count     
    movfw   units               ;zero at start-up, incremented later by button
    call    Binaryto7seg        ;get led segment data corresponding to value of 'units'
    movwf   LED1
Shift_bits:
    rrf     LED1
;determine state of data bit  
    btfsc   STATUS,C        ;is the data bit '1'?
    bsf     PORTC,0         ;yes, copy the data bit to the port bit
;data clk        
    bsf     PORTC,1         ;clk pulse low to high shifts data bit into Q0 74HC164
    bcf     PORTC,1         ;clk pulse low
    bcf     PORTC,0         ;set it to '0' if it had been set to '1'
    decfsz  shift_count
    goto    Shift_bits
;turn the digits on/off
    call    Display
;test the switch input    
    btfsc   PORTA,0                 ;is RA0 low (switch pressed)?
    goto    Main                    ;no
;count up    
    incf    units                   ;yes
    movlw   .10
    subwf   units,w
    btfsc   STATUS,Z
    clrf    units
;test the switch input    
    btfsc   PORTA,0                 ;is RA0 high (switch released)?
    goto    Main                    ;yes
    call    Display                 ;no
    goto    $-3                     ;loop until switch released     
 
    goto    Main                    ;no
    
;__________________________________________________________________________________________________________    
   
Display:
;Digit_on_time:
    bsf     PORTC,7         ;Drive the mosfet to show the digit   
    clrf    TMR2
    btfss   T2_done
    goto    $-1
    bcf     T2_done  
;Digit_off_time:    
    bcf     PORTC,7
    clrf    TMR2
    btfss   T2_done
    goto    $-1
    bcf     T2_done
             
    return