Jon De Schrijder schreef:
> On Tue, 23 Mar 1999, shevek wrote:
>
> > On Mon, 22 Mar 1999, Marco Antonio Simon dal Poz wrote:
> >
> > > On Mon, 22 Mar 1999, shevek wrote:
> > >
> > > > On Mon, 22 Mar 1999, Marco Antonio Simon dal Poz wrote:
> > > >
> > > > > For the most part of diskroms, DMA can be in page 1, because they have
> > > > > access to FDC through addresses 7FF8h-7FFCh and also BFF8h-BFFCh, and they
> > > > > transfer a small routine to F1BFh (or something like that) that allows a
> > > > > disk transfer to happen in page 1.
>
> I don't think this is true.
<snip>
Yes it's true , on all philips , exept for some old VG8230 , also #BFF8 - #BFFC is
used
for accessing the fdd controller , a little code will be placed inside the sector
buffer
and used to transfer data to page 1.
when you put the "fast" diskrom from a NMS8250 inside the VG8230 is will crash
when you want to load msx-dos
when you make a little modification and "mirror" 7FF8 etc to BFF8 it will work
erik de boer
--
>
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