Hi Andre,
>
> I have got your example code thank you very much for
> replay. I did not try it  yet but this is what I tried and
> it did not work.
>
>         BTFSS    PORTB,7                ; TEST   SWITCH
>         MOVLW    B'00000001'         ; TIMER USES INTERNAL CLOCK
>         BTFSC    PORTB,7                ; TEST SWITCH
>         MOVLW    B'00100000'          ; TIMER USES EXTERNAL CLOCK
>         MOVWF    OPTION_REG
>
> I put this code right after setting bank1.
>
> when I try with out bit test each one separately works.
> My question is why bit test doesn't work.
> Before this I have
>     BSF    STATUS,RP0
>     MOVLW    B'11110000'
>     MOVWF    TRISB


I think the problem is that you must set to bank 0 first when
bit-testing PORTB because bank 1 holds the TRIS registers.

My previous code also had the flaw.  I should have been:

        BCF     STATUS,RP0              ;set to bank 0
        SWAPF   PORTB,W         ;swap nibbles
        ADDLW   B'00011000'             ;reverse timer bit and shift left by 1
        ANDLW   B'00010111'             ;mask needed bits
        BSF     STATUS,RP0              ;set to bank 1
        MOVWF   OPTION_REG              ;put in OPTION

I hope this helps.

Reggie