Jinx escreveu:
> I can see that you could use several methods to get the pulse you want ;
>
> >From 1us up to a certain length
>
> bsf
> (X * nop)
> bcf
>
> >From there to another length, an 8-bit decrement
>
> bsf
> decfsz X
> bra $-1
> bcf
>
> After that I think you'll need to go to a 16-bit decrement. For example
> 200us is 1000 instruction cycles

Don't forget that you may insert several NOPs or goto $ + 1 before the
decfsz:

    bsf

    goto   $ + 1
    decfsz X,f
    goto   $ - 2

    bcf

I like this one:

    movlw   N
L: clrwdt
    addlw   -1
    btfss   STATUS,Z
    goto   L   ; Each loop takes 5 Tcy =3D 1us @ 20MHz

Longer time:

    movlw   N
L: clrwdt
    goto   $ + 1
    goto   $ + 1
    nop
    addlw   -1
    btfss   STATUS,Z
    goto   L   ; Each loop takes 10 Tcy =3D 2us @ 20MHz


Regards,

Isaac

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