Just an update on this: I used a scope without a cape (because I don't own one, and estimated backorder on MCM is 52 days). I verified no life on AUD_DOUT P9_28, but I _do_ see life on pins 19 and 20, which are the I2C SDA and SCL lines. As soon as I commence sound output, the SCL goes live with a regular pulse, and we see an I2C START on SDA.
So I think this means if I had an actual I2C slave responding to the proper address, the BBB would then start outputting serial data on its I2S output pin, P9_28. But without this, I won't see anything. So it's not a driver or overlay issue, it would appear. On Saturday, July 4, 2015 at 12:44:00 PM UTC-6, Colin Bester wrote: > > Yes I have a scope and will run tests for you when I get back to my desk. > > Sent from my iPhone > > On Jul 4, 2015, at 11:15 AM, [email protected] <javascript:> wrote: > > Colin, > > That would be phenomenally helpful! Do you have a scope? > > I'm curious if you see any life on pin 28 of the P9 header with and > without a cape. I suspect you will see data with the cape (because the DAC > on the cape board is talking to the BBB's processor), but nothing without > it. > > I unfortunately don't have a way to "fake" the cape. > > > > On Saturday, July 4, 2015 at 9:23:59 AM UTC-6, Colin Bester wrote: >> >> If it'd help I could run same tests for you with and without audio cape >> and test the theory - I am running bone68 but suspect results will be the >> same - it'd be good to know if you can see output or not. >> >> On Saturday, July 4, 2015 at 10:19:59 AM UTC-5, [email protected] >> wrote: >>> >>> >>> Latest thoughts on this: I think perhaps the problem is that I should >>> not expect to see serial data from P9_28 (I2S serial data out) without an >>> actual Audio Cape. There are probably I2C (control) and I2S (audio >>> content) requirements, such as clocks and so forth, that are required >>> before the BBB will output data. >>> >>> Unfortunately, I know virtually nothing about hardware. >>> >>> I would just buy an Audio Cape, but I have not seen them in stock >>> anywhere for the past month, and there seems to be no indication of when >>> they'll be available again. >>> >>> >>> >>> >>> -- > For more options, visit http://beagleboard.org/discuss > --- > You received this message because you are subscribed to a topic in the > Google Groups "BeagleBoard" group. > To unsubscribe from this topic, visit > https://groups.google.com/d/topic/beagleboard/xfv4BY1AiEA/unsubscribe. > To unsubscribe from this group and all its topics, send an email to > [email protected] <javascript:>. > For more options, visit https://groups.google.com/d/optout. > > -- 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 [email protected]. For more options, visit https://groups.google.com/d/optout.
