Hi again, As far as I know, in most cases audio cartridges can be made to work NEARLY perfect with turbo-circuits, but often not 100% perfect. The problem here is essentially in the turbo-circuit (6/7 MHz. or my own MSX super turbo): when the computer is running at turbo-speed, and some music device is accessed, the turbo-circuit will switch back to the standard 3.58 MHz. But no matter how it does this, in practice at least for a bit, the machine will still have run one or more clock-cycles on turbo-speed, AFTER the particular device was accessed, before the system is actually switched back to a lower speed. This problem also goes for other than music devices, but for these other devices, this seems to be no problem in practice. Different turbo-circuits perform differently here, but not that much. The only real solution would be a more sophisticated circuit. Possible to make it, but: more complicated, bigger, more expensive, less reliable, .... To let an audio cartridge work with turbo-circuits, these basic steps are needed: Construct an independent clock-source, as required for the cartridge (usually 3.58 MHz.). Make sure the connection to the computer's clock signal (cartridge pin 42) is disconnected. Preferably do this close to the cartridge-connector, that makes it easier to see what's been modified. Connect the 'cartridge-side' of this clock signal to the independent clock source. At least for MSX-Music (FM-PAC/K) and MSX-Audio cartridges (Music Module), the turbo-circuit will have to be switched back, when this device is accessed. In the 'standard' construction of turbo-circuits, these are switched back upon access to ANY I/O-port (using Z80 IORQ-signal). In that case, all is well. But in some cases, it might be switched back only on access to certain hardware, like the VDP (and maybe nothing else). If so, I suggest you go back to the 'default' construction, by hooking up the Z80 IORQ-signal to 1 of the inputs on the turbo-circuit. If these steps are done properly, no software modifications are needed. SCC seems to work fine on 7 MHz. (probably even higher), if supplied with a fixed 3.58 MHz. clock. I wouldn't know about Moonsound (haven't got one to try) When you need a crystal oscillator: you could use a circuit like I used in my MSX super turbo circuit, preferably with somewhat higher capacitor values (47 pF or such). It's better to construct this from single components for 2 reasons: cheaper (ready-made crystal oscillators are usually more expensive, I wouldn't know why, but they are), but more important: it's easier to fit such single components in a cartridge somehow, if little space is available. Sometimes, you can also use parts of the circuitry already in such a cartridge. Greetings, Alwin Henseler ([EMAIL PROTECTED]) http://huizen.dds.nl/~alwinh/msx (MSX Tech Doc page) http://www.twente.nl/~cce/index.htm (computerclub Enschede) **** 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/) ****
