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Re: IIgs peculiarities

  To: Michael J. Mahon
On Mon, 23 Feb 2009 17:33:35 -0800, Michael J. Mahon wrote:

> Jeff Blakeney wrote:
>> But the Ensoniq is able to deal with 128 KB of RAM connected to it.  I'm
>> surprised no one has done a hardware hack to piggyback the RAM and
>> double the size of the sound buffer.  Imagine the MIDISynth wave banks
>> that could be made with twice as much room for samples.  :)
> 
> I wonder if the toolset allows for 17-bit addresses, or the equivalent
> bank-selection bit...

I'm not sure if the toolsets allow it but it might be possible to patch
them to do so.  I just did a quick look online and in the IIgs Hardware
Reference and it looks like the 5503 only has 16 address lines but does
have a Bank Select on pin 40.  In the IIgs schematics, pin 40 looks like
it isn't connected.  The only way to set that pin's state is through the
Wavetable Size Register where bit 6 is always zero on the IIgs at
present because it doesn't have another bank of memory to deal with.

The problem is, like you implied above, putting the samples into memory.
I'm not exactly sure how the Sound GLU, auto incrementing address bit
and the bank select bit in the wavetable size register will all work
together.  There might need to be more done to be able to put samples
into the high memory bank.