Mon, 29 Dec 2014 19:25:14 -0800 от chris hermansen <clhermansen@xxxxxxxxx>: >Sergei and list, > >On Mon, Dec 29, 2014 at 5:42 PM, Sergei Steshenko < steshenko_sergei@xxxxxxx > wrote: >>Hello All, >> >>first the background. >> >>I am considering building a semi-DIY DAC based on CM6631A and, say, PCM1794. >> >>I want to buy a ready made USB -> I2S converter board - like, for example, this one: http://www.aliexpress.com/item/CM6631A-24bit-192khz-USB-to-Coaxial-and-Optical-fiber-SPDIF-and-I2S-by-LJM-New-version/2030271910.html and build the DAC proper and analog output part myself. >> >>So my questions are related to CM6631A as USB -> I2S converter and are the following: >> >>1) is USB asynchronous mode (i.e. CM6631A board XTALs are used as clock generators, and computer is a slave, i.e. audio transfer rate is determined by the XTALs) ? >>2) MCLK of I2S can be various multiples of sample rate - is this supported ? According to what I found on the web Windows driver supports this feature; >>3) CM6631A has embedded 8051 controller, so can new CM6631A firmware be loaded into the board memory under Linux ? CMedia provides such a utility for Windows. > >All the Schiit DACs (Bifrost, Gungnir, etc) use the CM6631A for their USB interface. My Bifrost is slightly older and uses the CM6631 (without the A) which at minimum does not support 176.4 at least in the Schiit incarnation, though it does support "everything" else (44.1, 48, 88.2, 96, 192) > >Given that limitation, if you want info based on my CM6631 let me know. I have to say right off the bat that 1) the CM6631 does work in asynchronous mode 2) see comment above and 3) no idea. > >Or, perhaps another Schiit owner with more modern gear can help you out? > >-- >Chris Hermansen · clhermansen "at" gmail "dot" com > >C'est ma façon de parler. "2) see comment above" - I think you misunderstood my question here. There are two things: a) supported audio sample rates; b) MCLK expressed as sample_rate * K, where K, according to, for example, PCM1794 datasheet, can be one of ( http://www.ti.com/lit/ds/symlink/pcm1794.pdf ) : " System Clock: 128, 192, 256, 384, 512, or 768 fS With Autodetect " - the above numbers are for fS=44100HZ, for higher frequencies big Ks are not supported - for example, on p13 of the datasheet one can see that for fS=192000Hz max K is 384. So, my question was about setting the K. For more info/examples of MCLK in I2S you can look into, say, http://www.ti.com/lit/ds/symlink/tas3202.pdf I would still be interested to see output of amixer scontrols . Thanks, Sergei. ------------------------------------------------------------------------------ Dive into the World of Parallel Programming! The Go Parallel Website, sponsored by Intel and developed in partnership with Slashdot Media, is your hub for all things parallel software development, from weekly thought leadership blogs to news, videos, case studies, tutorials and more. Take a look and join the conversation now. http://goparallel.sourceforge.net _______________________________________________ Alsa-user mailing list Alsa-user@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/alsa-user
