Re: [openMSX-devel] MSX-MUSIC memory mapped

[Wouter V. <wou...@st...>]

On Fri, 30 Nov 2001, Maarten ter Huurne wrote:

> On Thursday 29 November 2001 23:18, you wrote:
>
> > MSX-MUSIC is normally controlled via IO-ports 0x7c and 0x7d. I remeber
> > that it could also be controlled via memory instructions (necessary if you
> > want to use 2 MSX-MUSIC's at once). Anyone knows exactly how?
>
> Sean Young knows. I searched for info on msxnet and after a while found it;
> the info is not in the obvious location but it's there.
>
> Quote from:
> http://www.msxnet.org/tech/megaroms.html
>
> ===
>
> FM PAC
>
> This about the original FM PAC, the Panasonic. This cartridge has 64kB ROM
> and 8kB SRAM. The ROM is in memory area 4000h-7FFFh. By writing to address
> 7FF7h, you can switch 16kB blocks (switches the whole ROM area). This address
> is read/write but since there are only 4 pages, bits 2-7 are always zero.
>
> Special address (always active):
>
>         7FF4h: write YM-2413 register port (write only)
>         7FF5h: write YM-2413 data port (write only)
>         7FF6h: activate OPLL (read/write)
>         7FF7h: ROM page (read/write)
>
> Address 7FF6h also has a special function, but for the sound chip. You have
> to set bit 0 to active the OPLL. Only bit 4 and 0 can be set or reset, the
> other bits are always 0. I don't know what bit 4 is for.
>
> The SRAM can be actived in only this way: write 4Dh to 5FFEh and 69h to
> 5FFFh. Now 8kB SRAM is active in 4000h - 5FFFh, and the last two bytes are
> the two values you have just written. If you write any other value than the
> two above, the SRAM will disappear, and the usual ROM will appear. When the
> SRAM is active 6000h - 7FFFh is FFh except for 7FF7h and 7FF6h.
>
> The .pac data files have the following format: first a header ("PAC2 BACKUP
> DATA") and then the 1FFEh bytes data.
>
> ===

Thanks.

Now, what about the Turbo-R build-in MSX-MUSIC. It has 16KB ROM, do the
addresses 0x7ff4-0x7ff7 have the same meaning? Or at least 0x7ff4-0x7ff5?
What about FM-PAC-clones?

BTW: David, have you figured out how FM-PAK stereo works?

Wouter