I bet is would work find in assembly....

~ Bob Ammerman
RAm Systems

> -----Original Message-----
> From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf
> Of Isaac Marino Bavaresco
> Sent: Friday, August 28, 2015 11:02 AM
> To: Microcontroller discussion list - Public. <piclist@mit.edu>
> Subject: Re: [PIC] XC8 Bit Technique?
>=20
> I just found that my BAM() routine took more cycles than the time of the
> LSB, so it messed things up.
>=20
> I was using 'memcpy', that took alone 390 tcy and a loop that took 182
cycles.
> After some code changes, the routine works OK.
>=20
> There was another mistake that made the delay of the previous bit being
> used, instead of the current bit.
>=20
> Expecting a PIC16F work OK for this application may be wishing too much.
>=20
>=20
> Isaac
>=20
>=20
>=20
> Em 28/08/2015 10:30, Isaac Marino Bavaresco escreveu:
> > Hi Josh!
> >
> >
> > I did not know BAM, but after I read your post I found it interesting,
> > so I wrote some code to test an idea.
> > It seems to be working OK, please see the attached file.
> >
> >
> > Cheers,
> >
> > Isaac
> >
> >
> >
> >
> >
> > Em 27/08/2015 11:10, Josh Koffman escreveu:
> >> Hi all,
> >>
> >> Amongst all the other things on my plate right now, I'd like to make
> >> a small library to do Bit Angle Modulation on some of my projects. I
> >> made one years ago in assembly, but now I'd like to do it in XC8.
> >>
> >> For reference, there are some great posts on BAM on the PicBasic forum=
s
> here:
> >>
> >> http://www.picbasic.co.uk/forum/showthread.php?p=3D45597
> >> http://www.picbasic.co.uk/forum/showthread.php?t=3D10564
> >>
> >> Because the PIC will be doing many things, I am considering using a
> >> high priority interrupt for the BAM, but keeping my high priority ISR
> >> as small as possible (which is probably a good idea regardless). To
> >> accomplish this, I want to create the 8 "slices" that I will output
> >> in my main line, so that all the BAM ISR has to do is take that
> >> variable and put it on the port.
> >>
> >> My question is, what would be the best way to handle this in C? When
> >> I did it in assembly I used a rotate (rotate right if I remember
> >> correctly), then read the carry bit. But then I was also doing it at
> >> the moment of outputting, so there was no intermediate stored
> >> variable.
> >>
> >> My current thought is to define a typedef that lets me access the
> >> individual bits, then a bunch of if/else statements that check the
> >> bit of the source value, and if it's a 1 set the bit of the
> >> corresponding "slice" variable. This would result in a lot of if
> >> statements though, so I'm wondering if there's a slicker way to do
this.
> >>
> >> I'm trying to avoid dropping into ASM to do this for a few reasons.
> >>
> >> Any thoughts?
> >>
> >> Thanks!
> >>
> >> Josh
> >
> >


--=20
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