Re: SFX Expander programming and VICE

From: Gábor Lénárt <>
Date: Sat, 26 Nov 2011 11:31:08 +0100
Message-ID: <>
On Sat, Nov 26, 2011 at 02:12:20AM +0100, Groepaz wrote:
> if you manage to come up with a small test program (that works on the real 
> thing) - PLEASE post a bug on the vice bugtracker :) soundexpander/sampler are 
> both kinda hard to test with the original software.

This is a quite large C64 prg file. It is only large because of the included
"song". Also if it produces any sound somehow (it should, but it does not
work for me with VICE) it may sounds poor, since the timing information is
not so correct yet. Anyway, if I ever can make it hearable, I would clean
the rest of the program and give the source, just first I like to make sure
it works at all: at this point I am not 100% sure if it is my fault that
it does not work or not. Unfortunately I have no real hardware (I have C64,
but not the cartridge) that's why I would need VICE to test.

The heart of the code is just this:

 STA $DF40 ; YM register select, register number in A now
 STA $DF50 ; write the register data, data in A now
 Looping ...

There are enough instructions between the two STAs and between do the
looping, so the needed minimal delay after YM register select/data write is
provided in this way.

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Received on 2011-11-26 11:00:04

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