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ESSFM

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First post, by AllTinker

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Newbie

One of my primary retro PCs is a Compaq Deskpro EN P2-400 with an integrated ESS Audiodrive 1869F, however it's always had an annoying issue: FM synthesis doesn't work in DOS regardless of any setting I've found to mess with.

Tonight I finally got around to having a look through the datasheet, tried poking around a little, and at last I have it working!

Turns out that the "Music DAC" can be assigned to ONE of three different things; the ESFM synthesizer, a wavetable interface or an I2C bus - my card was attempting to assign it to both of these non-ESFM inputs!

I've put together a little utility to correct this, called ESSFM, which you can download here. The download includes a text file with usage/deployment details.

All it does in the end is do a software reset of the ESS Audiodrive, clears two erroneous bits (allowing the music DAC to become available to the ESFM synthesizer), and ensures the ESFM is in OPL3 mode.

This is of course a works-for-me sort of deal. I can't find any reference to anyone else who's had this problem - it's quite possible this is just something wrong with my specific PC somehow, but I figured no harm in putting this out there just in case it helps someone else!

Also I have no idea if it'll work on Audiodrives other than the 1869, although you can force the program to run anyway via command line option if you're willing to try (should be fairly safe)...

Reply 1 of 3, by Jo22

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l33t++

Thanks for sharing! 😀

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