Re: PSG pitch table, wave re-trigger, 4-bit PCM & YM/AY differences

[Ricardo Bittencourt Vidigal Leitao]

On Fri, 9 Jul 1999, MkII wrote:

> What's the recommended method to setup PSG for 4-bit PCM playback? Setting
> the lowest pitch? Disabling both noise & tone in the mixer?
>

        Disable the mixer. This way the output becomes grounded on level
"1" regardless of the internal counter states. 

        About your other question, as far as I know there is no way to
change pitch without getting "pops". The output of the psg is something
like this:
             _____     _____     _____
        _____     _____     _____

        When you change the pitch (from a lower frequency to a high
frequency), you may get this:
             _____     ____   ___   ___
        _____     _____    ___   ___
                           ^ 
                           I think this transition is the "pop" you hear.

        The only way to avoid the pop would be changing the psg register
when is wave is on level "0". But I know no way to detect when the wave is
on level "0"...
 
        About video decompressing on msx... Did you people never saw VIP
(Video Player)? It plays compressed video and compressed audio on a msx1
with megaram. The video uses a variation of the RLE algorithm and the
audio uses a variation of the ADPCM. All of this is done by software in
real-time. You can get VIP at http://www.lsi.usp.br/~ricardo/msx.htm

        About FudeBrowser... Does anyone want to make WISE for MSX or WISE
for Java? I can give my WISE lex/yacc sources to anyone interested. The
HTZ specs will be posted in this list still this week (I just need to
finish writing them :)

----------------------------------------------------------------
Ricardo Bittencourt               http://www.lsi.usp.br/~ricardo
[EMAIL PROTECTED]  "Ricardo is subtle, but malicious he is not"
------------ Say NO to Coca-Cola. Drink Tubaina. ---------------


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