Re: Atari ROM port ISA

[Michael Schmitz <schmitzmic@googlemail.com>]

Hi Thorsten,
>> Thanks for explaining this to me - to be honest I've never cared too
>> much about ISA and friends.
> No problem. (I practically grew up with them, so while the knowledge
> isn’t fresh, some is there.)
I grew up without computers - the first I used was a TR440 mainframe :-)
>> I'll check the layout - my guess would be that there's no memory
>> read/write selects wired up on the adapter. The RTL8019 doesn't need
>> them, the ISP1160  on the NetUSBee doesn't need them either.
> I’d guess the same. You’d need them for things like an ISA graphics
> card, but not (most) I/O devices.
Only /IOW and /IOR are wired up. Only A0 through A4 are wired up (from 
A9-A13).
>> If someone ever comes up with a way to hook up a fully featured ISA
>> slot to the ROM port (mapping ports 0x00 to 0x7f to IO and above to
>> mem access should be possible) we might revisit the code. For now,
>> anything except for 8 bit IO can be turned into dummy functions or
>> compile warnings.
> Might be nice, if possible. But for now, that would indeed be
> the way to go (and clean up code).
I've had a look at the NetUSBee docs and see that the USB part of it 
does require 8 bit writes but little endian 16 bit reads. So we will 
need to retain the 16 bit reads for potential USB support there.

Cheers,

   Michael