I'm sincerely sorry if this is a dupe, but I cannot find the note I intended to post an hour ago...
I have followed the instructions here: http://elinux.org/CircuitCo:Audio_Cape_RevB I compiled the given dts file to obtain the dtbo. I have disabled HDMI (and HDMIN). And I've added the new device: 0: 54:PF--- 1: 55:PF--- 2: 56:PF--- 3: 57:PF--- 4: ff:P-O-L Bone-LT-eMMC-2G,00A0,Texas Instrument,BB-BONE-EMMC-2G 5: ff:P-O-- Bone-Black-HDMI,00A0,Texas Instrument,BB-BONELT-HDMI 6: ff:P-O-- Bone-Black-HDMIN,00A0,Texas Instrument,BB-BONELT-HDMIN 7: ff:P-O-L Override Board Name,00A0,Override Manuf,BB-BONE-AUDI-02 I do not have an Audio Cape (they're sold out everywhere) but a scope on P9_28 is a flat line when I push sound out: $ ./pcm -D default:EVM (pcm is the sine-wave generator in the alsa examples list, and it plays a tone just fine out the USB port with a Turtle Beach Amigo II USB adaptor) However, P9_25 does go from a sine wave when not running the above pcm program, to another sawtooth/sine wave half that frequency when I do run it. None of the other pins (28, 29, 31) show any life. I have no idea what's going on nor how to approach debugging this. Linux beaglebone 3.8.13-bone47 #1 SMP Fri Apr 11 01:36:09 UTC 2014 armv7l GNU/Linux BBB Rev C -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.