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AD193X Driver access through alsa

Question asked by NoExpert on Apr 5, 2013
Latest reply on Apr 10, 2013 by larsc

I am working with an EVAL-AD1939AZ board connected to a BF536 running uClinux 2011R1-RC3.  I appear to have a functioning system in that I can use the alsa util speaker-test to deliver audio.  If I provide a wav file and no destination speaker, it will loop through all 8 channels and I can hear the audio through a headset as it plays to a channel.  I have not used alsa before and was looking through the speaker-test code to determine how to access each channel of the AD1939.  It looks like speaker-test creates a buffer/frame large enough for all 8 channels and then stuffs the "channel" of the buffer with data for that particular DAC before handing it over to alsa.  I have been told for previous AD devices used here the channels appeared in /dev individually.  In the /dev directory I have controlC0, pcmC0D0c, pcmC0D0p, seq and timer which all appear associated with the driver.  Is this correct?  Is the application responsible for building the full buffer (frame) before handing it over to alsa for delivery to the AD1939?  Would the same be true for the ADC data coming back?