;Digital-RPM-Counter-with-16F628A
Device 16F628A
Xtal 4
All_Digital TRUE

Dim COUN As Word        ; COUNTER Variable 0 to 999
Dim ONES As Byte        ; LSD , DIGIT 0 For ONES 0 to 9
Dim TENS As Byte        ; DIGIT 1 For TENS 0 to 9
Dim HUNDREDS As Byte    ;MSD , DIGIT 2 For HUNDREDS 0 to 9 

Output PORTB            ;TRISB = %00000000  output
PORTB = 0               ; Clear PORTB 
Input PORTA.0
Symbol Enable_ONES = PORTB.6       ;Enable 4511 for ONES
Symbol Enable_TENS = PORTB.5       ;Enable 4511 For TENS 
Symbol Enable_HUNDREDS = PORTB.4   ;Enable 4511 For HUNDREDS

COUN=0                              ;Clear COUN 

Main:

; Note :  Variable = Counter Pin, Period
COUN = Counter PORTA.0,1000     ;Period "1000 ms = 1 sec" time value to calibrate display 
COUN = COUN * 60                 ;scaling if you need it , to get RPM
COUN = COUN / 1                 ;more scaling if you need it 
If COUN > 999 Then COUN = 0     ; set to 0 if over count

Display: 
;COUN consists of   
ONES=COUN Dig 0
TENS=COUN Dig 1
HUNDREDS = COUN Dig 2 

PORTB=240 | ONES ; Sens ONES data           
; Note : 240 = %11110000 , (|) OR to use bit0 to bit3 for 7 segment 
;and make bit4 to bit7 high for enable function     

;Enable (LE) 4511 ONES digit by low pulse 
Low Enable_ONES : DelayMS 1 : High Enable_ONES : DelayMS 1     

PORTB=240 | TENS ; Send TENS data

;Enable (LE) 4511 TENS digit by low pulse 
Low Enable_TENS : DelayMS 1 : High Enable_TENS : DelayMS 1 

PORTB=240 | HUNDREDS ; Send HUNDREDS data

;Enable (LE) 4511 HUNDREDS digit by low pulse 
Low Enable_HUNDREDS : DelayMS 1 : High Enable_HUNDREDS : DelayMS 1  

GoTo Main   ; Loop again  
End