Re: Ideas about an analog-to-digital converter API

[Ken Hornstein <kenh%cmf.nrl.navy.mil@localhost>]

>Actually, audio has a way to set the analog input range: it has input
>gain control (multichannel, yet) as part of the mixer interface.

Hm, I looked at that, but I don't quite see how it's flexible enough.  For
example, the MAX197 (the A/D chip that is of interest to me) can be set
to go from 0 to 5V, 0 to 10V, -5 to 5V, or -10 to 10V.  The "gain" knob on
the mixer is an unsigned char.  I could set some "magic" gain values to
make that work, but it just feels ... wrong.  And there's not a good way
to query capabilies using that interface, from what I can see.

(And you can do other funky things with some A/D converters, like choose
between single-ended and differential interfaces - again, audio(4) just
seems like a bad hack for this purpose).

--Ken