> On Sep 28, 2015, at 01:03 , Jesse Cobra <[email protected]> wrote: > > > Ah. The DT overlay is configuring McASP for IIS, but not the TLV? Where is > > the TLV's configuration set? > > In the TLV audio driver. The driver is setting the codec to 2 channel TDM. > Which really is the same thing as i2s which is always 2 channels anyways. TDM > can be much more channels if you want. Anyways.
I saw in the code where it was setting it, but it's based on a "fmt" value that gets passed in from somewhere. Anyway, you're saying it doesn't really matter, so I'll ignore that particular discrepancy for now. > > I don't have a proper IIS analyzer, but I probed the pins with an > > oscilloscope, and they never change state. > > You do not need anything special for audio data, it is pretty slow anyways. > So a few simple questions. > > 1. Does the default audio cape work with whatever software you are running on > your BBB? I don't have a working audio cape; I've never been able to buy one (no one seems to have the Rev B in stock). I did just now try using the BB-BONE-AUDI-02-00A0.dts overlay. I get the exact same behavior. > 2. Check MCLK, BLCK, WCLK and the i2s/TDM RX/TX data with your scope with the > default audio cape, what do you get? > 3. Then with your audio cape check MCLK, BLCK, WCLK and the i2s/TDM RX/TX > data with your scope again. What is the result? Just DC 0V on MCLK, BCLK, WCLK, DIN, DOUT. The I2C bus definitely has traffic. -- Rick > > Last I worked on a custom audio cape for BBB I started with a working regular > audio cape and went from that with a break out board: > > https://dl.dropboxusercontent.com/u/82765462/LPAX/IMG_20150928_010158676.jpg > > -Jesse > > On Mon, Sep 28, 2015 at 12:18 AM, Rick Mann <[email protected]> wrote: > Thanks for the response, Jesse! > > > On Sep 27, 2015, at 23:09 , Jesse Cobra <[email protected]> wrote: > > > > B) the I2C commands to the CODEC set DSP mode, not IIS mode > > > > Because the default codec is doing 2 channel TDM, not 2 channel i2s. > > Ah. The DT overlay is configuring McASP for IIS, but not the TLV? Where is > the TLV's configuration set? > > > A) the McASP pins never do anything > > > You have looked at the pins on an analyzer? > > I don't have a proper IIS analyzer, but I probed the pins with an > oscilloscope, and they never change state. > > > > > > On Sun, Sep 27, 2015 at 10:12 PM, Rick Mann <[email protected]> wrote: > > I built a cape using the same codec as the BB Audio Cape Rev B > > (tlv320aic3104) =, and wired it up the same way to reduce the amount of > > Linux configuration I'd have to do to get it to work. I finally have it > > communicating over the i2c bus, and both the codec and the alsa sound card > > seem to be (mostly) properly configured in the device tree overlay > > (https://github.com/JetForMe/podtique/blob/v1/bbb/cape/Podtique1/BB-ENABLE-PRU.dts). > > > > But the McASP part of the interface still seems to do nothing. Looking at > > the pins with an oscilloscope, nothing comes out. I *think* I'm at a point > > where my ALSA configuration is wrong, but I'm not sure. > > > > Lending further credence to the ALSA config culprit theory is the fact that > > the i2c commands to configure the codec seem to be incorrect. In > > particular, when I run "speaker-test", the i2c commands that get sent to > > the codec set it up for DSP mode, not IIS/I2S mode. The DT overlay calls > > for IIS mode. > > > > Other parts of the DT overlay seem to be working very well. Linux enables > > the power regulators for the CODEC via a GPIO, and takes it out of reset > > via another GPIO before communicating with it. I watched the I2C traffic > > with an I2C protocol analyzer, and it looks solid (you can see it here. The > > first part is the cape enumeration, the codec comms start at transaction > > 49: http://pastebin.com/2VFPVBbq). > > > > On my board, I've got the differential line out L&R going to an on-board > > audio power amp. I haven't routed any of the other outputs (or inputs) from > > the CODEC. > > > > Anyone got any insight as to why > > > > A) the McASP pins never do anything > > B) the I2C commands to the CODEC set DSP mode, not IIS mode > > > > Thanks! > > > > -- > > Rick Mann > > [email protected] > > > > > > -- > > 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. > > > > > > -- > > 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. > > > -- > Rick Mann > [email protected] > > > -- Rick Mann [email protected] -- 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.
