Re: Support for YMF724 soundcards?

Sonata Kyuu (
Sun, 06 Dec 1998 00:54:06 +0900

Scott Murray wrote:
> On Thu, 26 Nov 1998, James Best wrote:
> > I, too, have looked into writing a driver for this chip family. As mentioned,
> > the PDF documentation online is unreadable, and I have contacted Yamaha about
> > reciveing a hardcopy.
> > I was unable to get my card operational with the oplsa2 driver, though I will
> > have more time this weekend to play with it.
> Thanks to Richard Tobin (, who pointed me to the
> file:
> From looking at the contents, the YMF724 is quite different than the YMF711
> (OPL3-SA2) and 715 (OPL3-SA3) chipsets.
> After skimming through the specs some more, there seems to be enough there
> to maybe allow getting the SB Pro (such as it is), OPL3, and MPU-401 up and
> running, but it probably will involve quite a bit of PCI coding. As for the
> using the real functionality of the card, there's no actual documentation on
> that in any of the PDF files I've poked around in. :( I am intrigued a bit
> by the technical specs; the chipset has the ability to support SPDIF
> connections and is AC-3 enabled. What does a soundcard with one of these
> on it cost?

I have done a little bit of experiment with an Atrend card that is
YMF724-based. I can use the supplied DOS-utils (which uses dos4gw, FWIW)
to config the card in DOS and then use loadlin to boot linux; then I can
load the sound modules (sb.o & opl3.o) and they work. I can use the mixer
and get FM sound. However the sb pro emulation part only does 8-bit
output and I don't have a program to test it, but I think it will probably

If I cold boot the system, the YMF724 is not enabled; the sound modules
will not load as they cannot detect the hardware. Using setpci to set up
PCI reg 40/41h enables the chip so that drivers will load. I believe reg
48/49h (DS-1 control Register) and 54/55h (Power Management
Control/Status) should be set as well. However, I do not know how to
setup the separate 16-bit codec, so no sound come out. The codec on my
card does not seem to be AC2 mentioned in the 724 data sheet. The marking


The logo is an overlapped sigma and a T. Any idea?

BTW, is AC97 a functional spec or an API spec? Do AC97 codecs has a
standard programming interface? 'cos that's what I suppose the above is.

And yes, the YMF724 has a build-in XG synth (but needs 32k external main
memory) but the pdf file does not contain programming info for it.

I will try to experiment with it a bit more.


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