[hatari-devel] EKO System and easter

Thomas Huth huth at users.berlios.de
Wed Jun 24 22:38:46 CEST 2009

On Wed, 24 Jun 2009 09:51:55 +0200
Laurent Sallafranque <laurent.sallafranque at free.fr> wrote:

> The result is exactly the same than if I use "with DSP"
> At 16 Mhz, the demo freezes and image and sound are not synchronized
> At 32 Mhz, everything is synchronized (demo stops when DSP code
> should start, music continues to play).

Ok, so this means that the timing problems are not related to the CPU :
DSP ratio, right?

> With my latest tests, I can notice a few things :
> * Sound is directly rendered by the 68030 (no DSP here).
> * Sound is really badly rendered (at 16 or 32 Mhz).
>   There's really a problem here and it's not a DSP problem.
>    When sound comes from 68030, but in falcon mode, do we use the 
> correct frequencies ?

Have a look at dmaSound.c ... I thing the frequency table should be

> * The synchro (image/sound) is dependent of the "processor speed".
>    There must be a timer somewhere which is not correctly computed
>    (In videl, or dma sound)

Could be related to the VBL ... as I already mentioned in another mail,
the Videl emulation does not emulate the screen timings right yet. VBL
is always triggered in 50 Hz, no matter which refresh frequency is
programmed into the Videl chip...
Have I already mentioned that the Videl code needs a major rewrite one
day? ;-)


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