the dac is a p.o.s. ak4421,there is a blank header under the usb port with pins (starting furthest from usb)
1 3.3 v 2 gnd 3 fsclk(master clock) 4 l.r.clock(left right clock) 5 xxxxx(see below) 6 blk (bit clock)
i am not sure what 5 is for native , as it does not to go to the ak4421. i removed the resistor and jumped it to the trace for pin 6 for the ak4421. interface as per ak4421 is either 24bit i2s or left justified depending on pin 8 high or low, pin is high (3.3) for all test conditions so i2s. BUT!!! will play 16/44.1 showing 44.1k on lrclk, 16/48k showing 48k on lrclk. 16/88k and 16/96k do play but only display 48k on lrclk(downsample) 24 bit does not work at all only output is static.
since the dac is 24bit msb i2s i can only assume this a problem with the aml 7238 controller. i cannot find a datasheet anywhere. no firmware upgrades anywhere .emails to wd and amlogic have gone un answered
interfaced to burr brown pcm1794 in i2s and work fine except above problems (same with both dacs)
so if you only intend on 16/44 or 16/48 great . if you intend on 24/96 as i do.... will need new firmware or a good datasheet to figure out what is going on. any suggestion welcome