Re: 8088 card and bank 15

Den Fri, 27 Oct 2017 10:16:55 +0200 skrev Michał Pleban
<lists@michau.name>:
> Mia Magnusson wrote:
> 
> > With the 8088
> > enabled the 6509 probably sees bank 15 regardless which bank is
> > selected. This would be nice to have verified by someone with a
> > working machine with the 8088 card.
> 
> I would have to think about a simple test. Right now I can only see
> that the computer crashes if the functions required to access DRAM
> (read sector and verify sector) are called without the 7th bit set.
> Theoretically, if the computer saw bank 15 instead of DRAM, they
> should work, just not read the data?

I'd try write or verify sector. That would read, not write, to various
adresses in bank 15. Then it's easy to check what was written to the
disk.

But it would probably be easier to just run some own code on the 6509
which runs in the little ram area in bank 15 and just pulls _BUSY2_ to
switch out the DRAM, and then checks what's visible in any other bank
than 15. (A monitor would probably be just fine to do most of this, I
don't know if there is a monitor included in the CBM-II ROMs).

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