frequency meter in PBP

[savnik]

Depending of your PIC characteristic, 50MHZ is easy to do, 1500 MHZ???

I have use external divider(:256)

Nothing hard, nothing clever at all. Set a Timer as counter, Clear it, enable it, do you samppling time,m stop it, read it display it. 4 code line or so.
.

Yes , i use the below code(from AN592)

asm
enabletmr0      macro
        clrf    TMR0
        bsf     _trisabuf,3
        movf    _trisabuf,W
        tris    PORTA
        endm

disabletmr0     macro
        bcf     _trisabuf,3
        bcf     PORTA,3
        movf    _trisabuf,W
        tris    PORTA
        endm        

        movlw   0x10                ;initialize ddra
        movwf   _trisabuf           ;       /
        disabletmr0
        movlw   0x37                ;set the option register  - B'00110111'
        option                      ;to measure high freq.
        clrw

        enabletmr0                  ;enable tmr0
        call    delay5mS            ;wait for 5mS
        disabletmr0                 ;disable tmr0
        call    getfreq             ;get freq in fhi and flo  
                
;delay1ms, is a very accurate 1mS delay for a 4Mhz clock.
delay1mS
        movlw   197
        movwf   _count1
        nop
        goto    $+1
        goto    $+1
dly1mS        
        goto    $+1
        decfsz  _count1, F
        goto    dly1mS
        retlw   0

;delay5mS uses delay1mS to get a very accurate 5 mS delay
delay5mS
        call    delay1mS
        call    delay1mS
        call    delay1mS
        call    delay1mS
        call    delay1mS
        movlw   4
        movwf   _count1
tweek5mS
        decfsz  _count1, F
        goto    tweek5mS
        return

getfreq
        movf    TMR0,W              ;get the tmr0 value
        movwf   _fhi                ;save in fhi
        clrf    _count1             ;keep track of the toggles
toggle1
        incf    _count1, F          ;inc for first
        bcf     PORTA,3             ;toggle the input
        bsf     PORTA,3             ;       /
        movf    TMR0,W              ;see if tmr0 incremented
        subwf   _fhi,W              ;       /
        btfsc   STATUS,Z            ;yes then skip
        goto    toggle1             ;no then toggle again
        comf    _count1, F          ;else complement count
        incf    _count1,W           ;and increment
        movwf   _flo                ;save in flo
        retlw   0                   ;return
endasm

@Savnik, Which PIC you want to use?

i use 16f88.