On Wed, Jun 15, 2016 at 09:14:39AM -0700, Clark Dunson wrote: > Hello Charles, Peter, and Mark > > Another progress report, some feedback, and a question. > > We have everything pretty much working now. > > The clocking configuration I identified in an earlier post, > (ie. MCLK1 begin fed from BBB McASP0 24.576 MHz, and BCLK > being derived from it) works, though we still have a patch to > arizona-core.c to make it so. Ready for any inputs on how we > can make this change so we can upstream it. > This week is very busy for me let me put together some stuff and get back to you next week on this one. I have some changes that add the stuff required but it probably needs to be reshuffled so we can get it upstream in a reasonable time frame. > Selecting single-ended mode vs. differential mode being a > pairwise choice (ie. one selection for IN1, not independently > for L/R), caught us by surprise and required a harrowing > ECO. (This selection appears to also not be supported by the > driver) In the end we had to abandon single-ended mode, as The wlf,inmode device tree entry lets you select between differencial and single ended. > the PGA acted in a manner that defied our understanding. To > wit: If we had a signal connected to IN2LP, (AC through 1uF > capacitor), then what we did with IN2LN was pivotal. If we > connected I2LN to ground, the signal would have large positive > offsets, eg. +0.5 on WAV scale of 1.0 to +1.0, with unity > gain set on PGA, Digital Volume, and mixer. Cranking the PGA > gain would rail the signal in a positive direction before we > had adequate gain. If we left IN2LN floating, we got closer > to zero-centered, but when we set PGA to +6dB, we got huge > negative offsets (-0.6 on WAV scale) and still we were dead in > the water. Finally we connected a 1uF capacitor to 1N2LN, and > set back to differential mode (default). Life is better now. Alas I am afraid you have exceeded my understanding of electronics here, you would need to discuss this with one of our hardware FAEs. I do know we have used both single ended and differencial in the past, but I am at a loss to explain what you are seeing there. > > In our status meeting yesterday, we concluded that our moving > forward with thousands of units would be benefited both on > our side and Wolfson’s by an FAE as a go between. Is your > Cupertino office still alive (we are in Bay area), or can we > get a point of contact? Is it Joao? Yes Joao is probably a good place to start, and we do still have the Cupertino office. Thanks, Charles _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
