Mail Archives: djgpp/2003/05/26/11:15:08
rogers AT westmont DOT edu (wfrogers) wrote in message news:<89ce6cc3 DOT 0305222021 DOT 77a9bb0d AT posting DOT google DOT com>...
> Charles Sandmann <sandmann AT clio DOT rice DOT edu> wrote in message news:<3ecd0b5c DOT sandmann AT clio DOT rice DOT edu>...
> > > the D page (in which data from the acquisition card is stored in
> > > 4-byte words), which doesn't work. The symptom is that data read from
> > > memory and written to screen bears little or no resemblence to the
> > > data that should be stored there from the acquisition card, and
> >
> > The code looks OK at first glance.
> >
> > Does it work under DOS (not Windows)? It could be that Windows is
> > interfering with you reading the memory. I would make sure you don't
> > have EMM loaded (safe mode command line boot, or from a floppy).
>
> Thanks, guys, for the help. I have it working now. The solution (in
> addition to some of your suggestions) was to specify port 0x262
> exclusively, using the outp() command. Cheers, Warren Rogers
Just a quick followup for anyone who is curious. I meant port 0x292,
not 0x262 (when I wrote the note I was away from the computer on which
the code is located and my memory was not so good). The ISA card
reserves this port and the D page for its DMA transfer of data. Also,
we removed the loading of EMM from the config.sys file as per an
earlier suggestion. Curiously, we still get a protection fault when
running in DOS (not windows) mode. Someone probably knows why this
might be the case, but at this point I'm not concerned since the code
is running fine from Win98 dos prompt. WFR
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