[OLPC-devel] making DC measurements with "mic in", progress

[Miller Puckette]

Hi OLPC developers (particularly Mark perhaps)

Simon and I have got as far as to verify that, with VREFD asserted on the
AD1888 codec, whatever voltage we put on the MIC input actually gets to
pin 21 of the AD1888 chip.  I think this implies among other things that
we are indeed using the "modded" board (in fact Jim found the solder blob).
 We only made two measurements, 0V and 2V, but that seemed to make the case
that we've made it to the codec.

Unfortunately, we still can't seem to get DC results out of the CODEC; some-
body further downstream is high-pass filtering the signal.  I doubt ALSA
would do such a thing and am only hoping there's another setting we need
to change in the codec.  I'm going to start looking through the codec doc
to see if I can find anything, but if anyone else can think of something,
I'd be eager to hear it.

thanks

Miller (and Simon)