0

Sigmastudio and I2S working unconfigured?

Ale D.

February 10, 2020 20:20

None

Follow

Hello Daniel

As you told me not to do I bought an I2S bluetooth receiver. ;)
I programmed it and hooked it up to the Hifiberry DAC+ DSP.
I havent done anything in Sigmastudio but it just "worked".

(It is connected to the only input, DATA IN 2)

The settings of the bluetooth module are as seen in the picture.
https://drive.google.com/open?id=1ttiALj_8IpwCwBeq-ECBFNBQxWRHFzfv

First I haven't configured the I2S and second I haven't added it to the dsp program.

As I have tested, the Raspberry and bluetooth sound do get mixed up and played together.

Now what surprises me the most is that it runs without any configuration in sigmastudio.

I thought I have to add it as seen in the dsp program here.
https://drive.google.com/open?id=1P-WD8NJGUQ1usdwauqS0GPZrzOGj1RvQ

Before I now upload this I want to understand it correctly.

After this test with the module just connected through cables and no configuration i am just not sure anymore that I have understood the whole system correctly.

Thanks for your advice and information!

• Facebook
• Twitter
• LinkedIn

8 comments

• 0
  
  HiFiBerry team February 11, 2020 07:53

  Looks like you were very lucky and the default profile that is installed on the board just is configured exactly like this boards needs it.

  Check out the SigmaStudio profile:
  https://github.com/hifiberry/hifiberry-dsp/blob/master/sample_files/dspproj/4way-iir-delay-mixer.dspproj
  
  You will see how the input is connected to the DSP and how it is configured.

  Best regards,
  Daniel

   

• 0
  
  Ale D. February 11, 2020 11:57

  Hello Daniel

  I seem to wrongly understand the DSP program. Isn't the connector below the RPI I2S the second I2S input?

• 0
  
  HiFiBerry team February 11, 2020 11:59

  I'm not sure what connector you're referring to.

• 0
  
  Ale D. February 11, 2020 12:06

  In the DSP Program I have linked above in the original post you can see how I thought it has to be done...
  I can send a picture of it in the evening.

  Anyway maybe I will just change the bluetooth boards I2S settings exactly to the ones of the DSP as they aren't yet and it does not work always.

• 0
  
  Ale D. February 11, 2020 22:18

  After looking at it I am more confused than ever .-.

  First my thoughts on the DSP Program

  

  The connector where I putted the VolumeBluetooth to is the one I meant with "below the RPI"

  

  I thought to have the second Input working I have to set the DSP program like seen in the pics above.

   

  Now what additionally confused me now is, that the I2S settings in your standard DSP program are completely different than what I have configured at the Bluetooth module.

  As stated on the Datasheet it has to be SDATA IN 2

  

  Now the Bluetooth Module Settings again:

  

  (Here I had modified the SDATA IN 1 because I havent seen that I only have SDATA IN 2 available)

  As they are completely Different I expected it not to work and I would say if it is truly like this, it is not able to work.

   

  Do you have any Idea of what I am messing around?

  Thank you beforehand :)

• 0
  
  Ale D. February 15, 2020 19:26

  Hello Daniel

  I grabbed my Oscilloscope and did some measurement.

  I measured the lrclk as well as the bclk which is the wordclock I assume.
  During one Period of bclk are 65 lrclk signals which would explain the one bit delay, then there are 64 rest which would match the settings from the profile, great so this is true.

  Then I measured the wordclock against the SerialData which looked funny.

  unstopped:

  

   

  Stopped: (just one word)

  

  There seem to be only 16 bit sended with a delay where the output is high, while the dsp expects 24bit I assume.

  So this seems to be truly just a random, in a straight way matching, connection.

   

  What I still do not understand is why the Input comes to the output whilst nothing is changed at the loadet profile. (The profile shown in the previous picture is not loaded, it's still the factory setting loaded)

   

  Thanks for your attention!

• 0
  
  HiFiBerry team February 16, 2020 07:17

  The DSP just uses left-justified 24bit data. If only 16 bits are used, that's perfectly fine, the other bits are just 0.

  The input is routed to the output, because luckily the DSP program that comes as the default profile in the DAC+ DSP routes this signal to the output.

  Best regards,
  Daniel

• 0
  
  Ale D. March 01, 2020 21:13

  Hello again
  
  I haven't yet taken a deeper look at the DSP program as it seems to do anything I want, without me understanding it. ;)

   - thank you a lot for all your support Daniel! -

  But as I had problems (quirks at low frequencies) with higher volumes (set from the bluetooth source), I changed the I2S settings of the bluetooth chip again.

  Now everything works great.

  

  So this post is just an information for everyone doing a comparable project.

   

  If someone really wants to build such a solution and needs more information or files, don't hesitate to contact me.

   

  Greetings from Switzerland and good luck for all your DIY stuff out there.