Re: A86: 5MHz


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Re: A86: 5MHz




Question I've been meaning to ask...
Does the screen hardware pull data directly out of the video memory, or
does the interrupt routine include code to dump the video memory to the
screen every iteration?  Although, now that I think about it, that is a
dumb question cause you can turn ints off and the screen works.  oh well

Chris Phelps wrote:
> 
> Probably has something to do with the screen refresh...tho i would think that
> would be other parts of the hardware that dont tax the cpu at all... guess i'll
> just have to start hacking on my 85 again and find out :o)
> Later,
> Chicane
> Aaron Curtis wrote:
> 
> > I found something sort of interesting about this...  if you turn off the
> > lcd while running the routine, it takes a good bit less time (80 vs. 90
> > seconds for me).
> >
> > Kirk Meyer wrote:
> > >
> > > Well, after performing a few tests. The TI-86 does not appear to run at
> > > 6Mhz. With totally new batteries, the CPU was clocked at about 4.8MHz. (With
> > > older batteries it is more like 4MHz.) This was tested with a routine that
> > > took 360,000,000 t-states. This means one of two things.
> > >
> > > [A] TI is lying. I doubt this, since I don't think they make 5Mhz
> > > processors. (maybe they do?) Also I doubt why TI would lie anyway.
> > >
> > > [B] Something is eating up that much processor time (this is with interrupts
> > > disabled by the way). Try the code for yourself, it's at the bottom...


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