:> BTW does anyone know how you can make your Audio (SCC, ...) work ok at
:> 7MHz?
:
:I think the answer NYYRIKKI gave is not correct.
:
:Just supply it with its own 3.58MHz clock signal. Build your own
:oscillator circuit in the cartridge (Parts are worth a couple
:guilders I think) and connect it to where the cartridge slot CLOCK
:signal would have gone. This clock signal need not be synchronized to
:the MSX bus; in sound cartridges it's only used as base frequency for
:the wave generator devices inside the FM circuits. (This is why the
:total output frequency shifts up one octave if running @7MHz) Only
:thing that may go wrong is replayer software that uses too strict i/o
:timing routines; maybe they need some extra wait-timing (eg NOP).

About the wait-timing...
On 7MHz (with delay when I/O-access), the timing is just on the edge of too
fast and ok. It will probably work on the one computer and won't work on the
other computer. For example, my MSX-Music works fine on 7MHz, but my
MSX-Audio (with a 3.5MHz oscillator circuit built-in) sometimes (not that
often) plays a wrong note... It will probably go completely wrong on
Advanced 7MHz. A way to solve this is to let the MSX-Audio send a short wait
to the computer everytime the I/O-ports are accessed. However, this is not
easy to build.

And the SCC, that one doesn't have problems with timing, for it works on the
R800 too and it is accessed using DMA, so there can't be any implemented
I/O-delay.

The MoonSound doesn't have trouble with the speed, for the software is
written (almost) correct; there are different drivers for different speeds.
And the music will sound ok on the MoonSound for it has got its own
oscillator built-in.


~Grauw


****
MSX Mailinglist. To unsubscribe, send an email to [EMAIL PROTECTED] and put
in the body (not subject) "unsubscribe msx [EMAIL PROTECTED]" (without the
quotes :-) Problems? contact [EMAIL PROTECTED] (www.stack.nl/~wiebe/mailinglist/)
****

Reply via email to