>Whoops! I re-read that an realized my spelling checker screwed up. I
>meant that "Paul Davis thought that you could NOT connect this to a
>cdrom drive output, but i have called a few vendors and the believe this
>is not the case "
>
>There is defiantly confusion on this issue. I talked to 8 vendors. 5 of
>them thought that you could connect the 2 pin digital out from a cdrom
>drive to the card at the cd-in port and 3 weren't sure. It is after all
>labeled "CD-ROM/Sync in" and there is a "Internal" setting on the
>IEC958 Input Connector' option
>
>There has to be a way to get this working...even if i have to call
>Germany.
i completely take back everything i said before. i'm sorry. i forgot
about this stuff.
ok, lets get back to where you were. yes, connecting it to that
connector and setting the 'IEC958 Input Connector' to "Internal"
should work, assuming that the cd player is generating actual IEC958
data, which is probably is. you may need to set the various IEC958
switches (these are common to all ALSA devices, BTW).
however, you won't hear anything just doing that because the
hammerfall doesn't have a mixer in the normal sense. what happens
to the signal is that unless the card is running, it will just vanish
into a black hole. the hammerfall runs every channel in sync with
every other channel, and it runs playback in sync with capture, so
there are only two states for the card: all channels on, or all
channels off.
what you need to be able to hear the CD signal is to put the card into
what i call "passthru" mode. this is something that AFAIK, only the
ALSA driver can do. it turns the card on, but disables interrupts so
that we don't waste CPU cycles handling them. the card will pass all
data arriving at input connector N to output connector N, and you can
hear the results (assuming you've got the output connected to
something that can use it).
i enclose below the script i use to do this (its been posted on
alsa-devel and lad a few times). but please note: as i said above, the
hammerfall has no mixer - its not like a conventional consumer
interface - and so as soon as an application opens the card, passthru
mode be turned off (the card has to be stopped when opened), and the
signal arriving at the IEC958 (S/PDIF) connectors will be lost until
the application starts the card running (and does not enable
monitoring on those channels).
also note that you cannot route the destination of the signal when in
passthru mode. it uses the hardware to just move channel N input to
channel N output. on the hammerfall DSP, this will be different.
let me know if you have more questions. sorry about my earlier
misinformation.
--p
#!/bin/sh
#
# turns "passthru" mode on a Hammerfall card on or off
#
CARD_ID="9652"
ALSACTL_FILE=/tmp/hammerthru$$
if [ "$1" = "-c" ] ; then
CARD_ID=$2;
shift;
shift
fi
if [ $# -lt 1 ] ; then
setting="false"
else
case $1 in
on|y|yes|true) setting="true";;
*) setting="false";;
esac
fi
cat << EOX > $ALSACTL_FILE
state.$CARD_ID = {
control.15 = {
comment.access = 'read write';
comment.type = bool;
iface = pcm;
name = Passthru;
value = $setting;
};
};
EOX
/usr/sbin/alsactl -f $ALSACTL_FILE restore $CARD_ID
status=$?
rm -f $ALSACTL_FILE
exit $status
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