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-   -   Support for Botic Linux driver (http://www.diyaudio.com/forums/twisted-pear/258254-support-botic-linux-driver.html)

miero 26th June 2014 06:46 PM

No, audio chip at BBB is always configured to receive MCLK externaly.

If the cape is not present then the low-quality "external onboard BBB" 24.576MHz clock is used. This MCLK signal is in this case available on P9_25 pin.

If you enable external cape, then that "external onboard BBB" clock is automatically disabled by driver and the MCLK signal from "external cape" clock/s incoming via P9_25 pin will be used instead.

So the P9_25 pin is used as MCLK output when cape is not present, and as MCLK input if the cape is installed.

palmito 26th June 2014 07:16 PM

Thanks again Miero, much clearer now!

ChrisMmm 28th June 2014 04:07 AM

Well I followed the instructions but getting no sound.

I had previously set up the BBB with connections to a 9023 DAC using the earlier Botic drivers on Debian using Squeezelite - that worked and continues to work after rebooting on that SD card (eMMC actually).

Tried the new .img using both MPD and squeezelite but no audio. Squeezelite clearly sees the BOTICAudio device and looks like it is playing but no sound. MPD seems happy enough playing one of the test files but still no sound.

Anybody else have this working? Could it be this is now 9018 specific?

twluke 28th June 2014 05:58 AM

Thanks for the new botic driver
 
Hi miero,

Thank you for opening this thread for the botic driver support and also for providing us the latest SD image with the new drivers.

After spending some hours for auditioning with this 3.15.1-botic1 kernel system, I'd like to report my experience with it, referring to your instruction and comments on the page from http://bbb.ieero.com/.

> The distribution has integrated support for automatic shutdown of BBB

I enjoyed this. Thanks for this beautiful tweak. I also have my own history of damaging BBB a few month ago. ;-)

> By default the file is resampled if 44k1Hz frequency or multiples is being played. This might/will introduce hearable artifacts.

I confirmed it. After applying external clocks, playing the test_44k1_16b.flac file via MPD, that was heard with musicality under the built-in clock, became quite noisy and this was the case with all of my Red Book sources. Is there any way to avoid this problem?

> 1) using web MPC interface

The MPC interface is well designed and easy to use for a quick glance at the files.

> play FILENAME

The play command worked well and was more flexible in dealing with 44.1k sources than MPD in terms of noise-free play-back.

> 3) remotely form another linux machine by bbbplay

I enjoyed this hacking via a remote linux machine operating virtually on my Mac but how can I avoid entering my password requested by the BBB server before playing music?

> Notice: it does not support DSD

I hope this will be supported in the future.

> Installed clocks are configurable via:
- kernel option snd_soc_botic.ext_masterclk

For the temporary external clocks, I used either Amanero Combo384 DDC or I2SoverUSB DDC from jlsounds, both having MCLK outputs of 22.5792 and 24.5760 MHz, setting snd_soc_botic.ext_masterclk to 3. With this condition, I confirmed the sound files were played with its original SR.

> DSD format can be enabled via:
- kernel option snd_soc_botic.dsd_format_switch

First with this setting enabled, I failed to play the test DSD files provided under the /data, which caused severe signal drops, unable to complete the sequence.

However, to my surprise, the same setting went quite well with my personal collection of DSD sources, mostly DSD128 recorded from old vinyls, and, IMHO, the current botic driver appears quite well designed for this particular setting, that appears far superior to playing DSD by MPD with BBB connected to USB-DDC.

> The BBB has 4 serializers and each one is capable to generate:
- one stereo I2S channel
- one mono DSD channel

Here is a problem for me. By default playing PCM requires the LRCK pin to P9_29 header and the same pin must be moved to P9_41 header for 2-channel playing of DSD. I may be wrong with this understanding, but, if not, is there any way to move back and forth on the fly between these formats?

Anyway, I'd like to thank you, miero, for your great work. Cheers.

twluke

miero 28th June 2014 04:11 PM

ChrisMmm, with new driver you need to use different data pin (P9_30), or set kernel option snd_soc_davinci.sermask=4 ... or 12 if you want 2ch DSD too.

twluke, lrck position is fixed on BBB. The Botic cape will remap/route pins to correct positions. That's why there is I2S/DSD format switch pin.

miero 28th June 2014 04:14 PM

twluke, for ssh without password you need to generate private key and install its public part on BBB ... Try Google for ssh-keygen and ssh-install-key (maybe).

ChrisMmm 28th June 2014 08:55 PM

Quote:

Originally Posted by miero (http://www.diyaudio.com/forums/twisted-pear/258254-support-botic-linux-driver-post3974761.html#post3974761)
ChrisMmm, with new driver you need to use different data pin (P9_30), or set kernel option snd_soc_davinci.sermask=4 ... or 12 if you want 2ch DSD too.

twluke, lrck position is fixed on BBB. The Botic cape will remap/route pins to correct positions. That's why there is I2S/DSD format switch pin.

OK, thanks, didn't read closely enough. Will try that.

ChrisMmm 28th June 2014 10:53 PM

Quote:

Originally Posted by miero (http://www.diyaudio.com/forums/twisted-pear/258254-support-botic-linux-driver-post3974761.html#post3974761)
ChrisMmm, with new driver you need to use different data pin (P9_30), or set kernel option snd_soc_davinci.sermask=4 ... or 12 if you want 2ch DSD too.

All good. Moved the pin on my I2S wiring harness. Tried MPD and test files first - all fine. Installed Squeezlite and tested - all fine. Haven't listened at length but my impression is I would be hard put to tell the difference between the BBB/Botic/I2S/ES9023 setup (with its re-sampling 44.1 to 48k) against my usual BBB/USB/ES9023 setup. This is great news, cant wait for the Cape!

Great work Miero.

miero 29th June 2014 02:14 PM

Quote:

Originally Posted by miero (http://www.diyaudio.com/forums/twisted-pear/258254-support-botic-linux-driver-post3974767.html#post3974767)
twluke, for ssh without password you need to generate private key and install its public part on BBB ... Try Google for ssh-keygen and ssh-install-key (maybe).

Sorry, second command is ssh-copy-id :)

twluke 29th June 2014 10:31 PM

miero:

> twluke, lrck position is fixed on BBB. The Botic cape will remap/route pins to correct positions. That's why there is I2S/DSD format switch pin.

Thanks for this info. As I'm not familiar with GPIO setting, I set up a 2-pole switch to alternate the connection from P9_29 and P9_41 to the main LRCK line toward the BIIISE via Teleporter. Things worked well for now.

However, here is one question. With the default channel configuration (-1), the sidedness of L-R channel on PCM is normal but is reversed on DSD play. Am I only one with this problem? I'll be happy if enlightened.

> Sorry, second command is ssh-copy-id

Thanks for this update. I'll try it later.

Regards,

twluke


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