Thread:CircuitCo talk:Audio Cape RevB/Audio Cape instructions/reply

Instead of Step 4 above you can add the following line - CAPE=BB-BONE-AUDI-02      to file /etc/defaults/capemgr and it will then get automatically loaded, not exactly at bootup but very very soon after boot. If you want to add further capes (I also have a GPIO add-on) then these can be included on the same CAPE line with commas separating each one.

There is an error (or at least an inconsistency) on the pdf ciruit diagram. The audio inputs are labeled as LINE1LP and LINE1RP which would lead one to turn on the LINE1 L/R inputs in alsamixer but you get either nothing or very low level breakthrough (depends on PGA gain setting). In fact these inputs actually connect to the LINE2L and LINE2R (pins 14,16) on the chip. One might thus expect to turn on LINE2 inputs in alsamixer but unfortunately another problem arises. Alsamixer see this chip as a DA830 and though many things on this cape's chip (3104) are the same; the register (17) within the 3104 for LINE2 is accessed on the DA830 by alsamixer's MIC3-LINE3L and MIC3-LINE3R. This means that you need to turn on "Left PGA Mixer Mic3L" and "Right PGA Mixer Mic3R" in alsamixer to get the correct inputs connected. Line level inputs will then record and playback. If you were using lower level input signals you could increase the "PGA [dB Gain ...] which I leave set at 0dB.

Alsamixer shows many functions that are not useable on this cape and does mix up the Capture and Playback items so I suggest pressing F5 to show "ALL". These are the settings I have turned ON (everything else OFF or set to 0) to get line level inputs and line level outputs.

PCM (max level); HP; HP DAC (max level); Left HP Mixer DACL1; Left PGA Mixer Mic3L; PGA [db Gain ...] (set to 0dB); Right HP Mixer DACR1; Right PGA Mixer Mic3R.

Note that you can also sent Mic3L to the Right mixer and vice-versa so you could create mono mixes.

Hope the above helps someone save a few days of pulling out their hair.