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Support for Botic Linux driver

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G

Greg Stewart

Member
Joined 2003
Paid Member
Ok, another question came up for me about power sequencing... Miero, any special power sequencing required when using a master clock feed from something like a Botic to the BBB? Does it come up with the on-board clock and switch over to the one on the cape? Or does one have to make sure the cape's clocks are powered and active before powering up the BBB? And are there any concerns about an active clock feed into the BBB causing problems similar to that caused by pulling the power with out a commanded shutdown?

Things like this keep me awake at night!

Thx!

Greg in Mississippi
 
M

miero

Member
Joined 2011
Greg, there is P9_14 pin that should be used to enable power to clocks - it is switched on after BBB is initialized by Botic driver. It will also shut down the clocks when BBB is powered down.

In other words... there should not be any voltage on any pins when BBB is not powered up -- the BBB manual is full of these warnings.
 
nautibuoy

nautibuoy

Member
Joined 2010
miero said:
Greg, there is P9_14 pin that should be used to enable power to clocks - it is switched on after BBB is initialized by Botic driver. It will also shut down the clocks when BBB is powered down.

In other words... there should not be any voltage on any pins when BBB is not powered up -- the BBB manual is full of these warnings.
Click to expand...

Hi miero. I've been 'wondering' along similar lines to Greg so can I just confirm my understanding...

I know from having loaded your Botic distro onto my standalone BBB that it defaults to using its onboard clock, otherwise it wouldn't run as it will be the only clock available at boot. I assume that your distro selects the best available clock based on the data that the BBB is receiving and 'disables' any other clocks. In other words, if there is, say, a circa 90MHz clock available on the Botic your distro will use that and disable the BBB's onboard clock? Assuming that is correct, is that just for the duration of that data stream (music track), defaulting back to the onboard clock at all other times? I'm thinking I may just leave my BBB permanently running and just power down the Botic/DAC/IV stages.

Thanks

Ray
 
M

miero

Member
Joined 2011
nautibuoy: there are several options how to combine 3 clocks (1 onboard and 2 external) ... for mor info check the documentation for "snd_soc_botic.ext_masterclk"

Driver could be reprogrammed to switch clocks each time when music stops, but... ES9018 requires active clock to process I2C. So the driver currently just switch to other clock right before playing the audio track with bitrate non-compatible with currently active clock.

But another GPIO pin of BBB could be used for controlling power supply of your DAC. Remember, you need some time to start it up and using P9_14 for this purpose would cut starts of the tracks.

And 90MHz is too much for BBB. I've written several times that datasheet specifies 25MHz (or 26MHz?) max.
 
nautibuoy

nautibuoy

Member
Joined 2010
miero said:
nautibuoy: there are several options how to combine 3 clocks (1 onboard and 2 external) ... for mor info check the documentation for "snd_soc_botic.ext_masterclk"

Driver could be reprogrammed to switch clocks each time when music stops, but... ES9018 requires active clock to process I2C. So the driver currently just switch to other clock right before playing the audio track with bitrate non-compatible with currently active clock.

But another GPIO pin of BBB could be used for controlling power supply of your DAC. Remember, you need some time to start it up and using P9_14 for this purpose would cut starts of the tracks.

And 90MHz is too much for BBB. I've written several times that datasheet specifies 25MHz (or 26MHz?) max.
Click to expand...

Thanks miero for the quick reply.

Yes, I know 90Mhz is way to high for the BBB; I simply assumed the Botic would use an appropriate divider when providing synchronous clocking to the BBB (which I understand to be necessary for bit perfect playback at all sampling rates), or have I misunderstood something somewhere along the line?

I think all I was asking, perhaps not very well, is what happens if the Botic is powered down while the BBB is still running?

Thanks

Ray
 
nautibuoy

nautibuoy

Member
Joined 2010
miero said:
Botic does not divide clock signal, and it could be powered down while BBB is running, but the current driver does not do that.
Click to expand...

Thanks miero. My misunderstanding wrt the divider.

With your current distro what would happen to the BBB if the Botic 'disappeared' (failed or powered off); presumably it would be OK if it were using its own clock but if using a Botic clock?

Ray
 
nautibuoy

nautibuoy

Member
Joined 2010
miero, another question if I may...

I would like to have an equivalent to the BBB Power button on the rear panel of my DAC so I can trigger a shutdown manually if I so wish.

I believe the Power button function is exposed on P9_9 and in order to achieve the function I require I need to insert a momentary action switch between P9_9 and ground. Are you able to confirm.

Maybe you'll now tell me that this function is included on the Botic?

Thanks as always

Ray
 
C

Chanh

Member
Joined 2013
Hi Miero,

Please excuse my ignorance as newbie to Linux. Actually, I got into linux because of your Botic driver. :)

I have been following the steps to setup my BBB from http://www.computeraudiophile.com/c...lack-mpd-music-server/comments9.html#comments
An externally hosted image should be here but it was not working when we last tested it.


When it is coming to install your driver for enable I2S, I followed instructions from hifiduino. However, the instructions were only for botic_driverV3.tar.gz. Since than you have updated to V3-2.img.gz, pls would you direct me how to get the uptodate Botic driver in "tar" format so I could closely follow the given instructions in putty?
If anyone here knows how to setup BBB with MPD via Miero's Botic driver, please kindly point me into the right direction!
An externally hosted image should be here but it was not working when we last tested it.


Many thanks in advance,
Chanh
 
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nautibuoy

nautibuoy

Member
Joined 2010
miero said:
nautibuoy:

1) Table 13, page 85 of BBB manual (in short, yes)

2) http://www.diyaudio.com/forums/twis...embedded-audio-applicance-32.html#post4016515

3) next question? ;-)
Click to expand...

Thanks miero.

Yes, Table 13 in the manual and the schematic on page 43 were what I was looking at; I just don't trust myself enough so sought confirmation.

Do you know, I looked at the Botic diagram you referenced and didn't see that switch. When I looked again the first thing I saw was....:ashamed:

Cheers

Ray
 
C

Chanh

Member
Joined 2013
miero said:
Chanh: Ah, it is much more simpler now than in these recipes, because there is prepared image that contains required components.

Step 1: download bbb-demo-botic-v3-2gb.img.gz
Step 2: ungzip file
Step 3: flash .img file to SD card
Step 4: boot BBB using that SD card
Step 5: login to BBB or use MPD web interface

A bit more info at http://bbb.ieero.com/
Click to expand...
Many thanks! Just realised I went the long route...!
Again, appreciated your reply.

Chanh
 
nautibuoy

nautibuoy

Member
Joined 2010
C

Chanh

Member
Joined 2013
nautibuoy said:
No problem running it from the SD card but I'll try flashing the eMMC and report back.

Ray
Click to expand...
Please keep us posted with your findings on eMMC? I went the long route because I was hoping to have the Botic driver bootable from eMMC instead of uSD.

Guys, I am currently having difficulty in getting MPD to update the library from my 2TB USB-HDD. The usb-HDD is mounted in "/etc/fstab" with addition code
"/dev/sda1/ /media/music auto auto, rw,...., nofail. 0. 0"
I also changed the library-directory in mpd.conf to "/media/music".
When I type "ls /media/music" after reboot, it shows all the folders, but I could never get MPD to update and showing the files inside MPaD, MPoD, or Web base player ympd.
It is however working with 4GB usb-flashdrive. Ofcourse, I have to change "sda1 to sda (only)".
Can someone or Miero please assist?
 
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