Thanks very much. I had noticed that it seemed to be divied by 4 but
wasn't sure thanks for the clarification.

Wesley

On Thu, 29 Jul 1999, Jim Robertson wrote:

> At 11:33 29/07/99 +1000, you wrote:
> >I am attempting to use this delay code from:
> >http://www.dontronics.com/rtc.html#pic2
> >
> >From what I can work out the equation gives the number of instructions
> >which are executed. I am using a PIC16F84 (10Mhz) and want to know who to
> >convert instructions to time. I have gone through th F84 data sheet and it
> >doesn't specificly say how many clock cycles are used per instruction. It
> >says 'cycles' but this is 1 or 2 and 0.1uS sounds a bit small.
>
> The internal cycles are the clock speed divided by 4. So at 4Mhz the
> instruction
> time is 1uS or 2uS. At 10Mhz it is 0.4uS or 0.8uS.
>
> Instructions that modify the program counter take two internal cycles and
> these
> are CALL, GOTO, RETLW, RETURN or anything that uses the PC as a destination
> such
> as a ADDWF PC.
>
> Jim
>
>
>
> >Thanks for your help in advance.
> >
> >Wesley
> >
> >The routine is below, it may have been mucked up by the mail program
> >(wrapping). The link above will take you to the original version.
> >
> >delay           movlw   0x001           ;standard delay routine. increase
> >w value
> >                movwf   count1          ; for increased delay
> >                movlw   0x001           ;can set up any delay by calling
> >delay1 (NB!)
> >                movwf   count2          ; with pre-set values in count1,
> >2, 3
> >                movlw   0x020           ;ex Myke Predko, piclist 4 Jan97
> >                movwf   count3          ;delay, (no of instructions)=
> >delay1          decfsz  count3,same     ;2 + 5*(count3-1) +
> >                goto    $-1             ;2 + (5*255 +2+5) * (count2-1) +
> >                decfsz  count2,same     ;2 + (5*255*256 +2 + 5*255 +2+5)
> >*(count1-1)
> >                goto    $-3             ;  =
> >                decfsz  count1,same
> >;5(count3-1)+1282(count2-1)+327684(count1-1)+6           &nbp;
> >                goto    $-5             ;        return                  ;
> >
> Regards,
>
> Jim Robertson
> NEWFOUND ELECTRONICS
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