Hello I am trying to interface a D2A (Ti PCM3070) to a BBB, over I2S.
Annoyingly - it *very nearly works* - but the audio that results is "scratchy". I can't quite tell why this is the case (or what exactly the mode of failure is) or what I need to do next. Basically it's interfaced in the same way the HDMI chip is for audio, and has a secondary I2C connection for configuring the chip. After boot, I can fire in the various required register settings into the chip with i2cset, and then just ffplay <whatever> and - success - audio coming out. But not quite right audio. Very nearly there audio. It sounds a bit like it's clipped (but adjusting that makes no difference), or a signed/unsigned issue, but it's really hard to tell. At first I suspected the output was down to the MCLK not being right in my initial tests (the 3070 assumes a different MCLK by default), but after setting the dividers in the PCM3070 it made no particular difference. I'm also trying to send 48kHz/24-bit audio (I do not need particular flexibility for my application) as per the MCLK, but that made no difference either. In fact it rather sounds the same even if I send 44.1kHz files. I have read reference to MCLK perhaps being the 'wrong phase'. I'm also digging into http://bbb.ieero.com/ and the kernel sources for McASP on the BBB - but I'm keen to avoid having to do custom kernel builds et al unless it's strictly necessary. Ideas? -- 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 beagleboard+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
