I2S audio with modem Gemalto Cinterion PLS8-E | Thales IoT Developer Community
January 17, 2017 - 11:29am, 3022 views
Hello
We bought miniSTREAMER USB/I2S sound card and we would like to use this sound card for playing audio wav file from computer and send converted I2S
audio stream to the ****m Cinterion during voice call. Modem Gemalto Cinterion PLS8-E support I2S audio.
I did following tests:
I did voice call from ****m Cinterion and played audio wav file through miniSTREAMER sound card into computer and send I2S stream to Cinterion
****m.
I’m not sure that I connected correctly all necessary PIN because sound which goes from Cinterion ****m into my mobile phone is strange.
I attached audio wav files.
In case that I set Cinterion ****m as SLAVE (for receiving synchronization) and miniSTREAMER as MASTER(for sending synchronization) I recorded
strange audio file "cinterion slave and miniSTREAMER master.wav". I attached this file. Original audio wav file which I played through miniSTREAMER
was "original sample.wav". I attached zip file with audio wav files (password is: audio)
In case that I set Cinterion ****m as MASTER (for sending synchronization) and miniSTREAMER as SLAVE (for receiving synchronization)) I recorded
only silent audio file.
I set on miniSTREAMER audio sound card following settings:
2 channels, sample rate: 16kHz, samples: 16bit
I would like to ask someone who has similar experiences with I2S audio and miniSTREAMER.
1.I would like to know that I connected correctly mentioned two devices (I attached schematic.pdf file)?
2.
On white board Cinterion DSB-Mini board I didn’t find MCLK pin (master clock) and miniSTREAMER sound card has this pin.
I’m not sure that MCLK pin is not necessary for I2S audio?
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I set following settings on Cinterion ****m regarding I2s audio (I have to say that I have tried all possible combinations).
I suppose this settings should be good.
at^saic=3,1,1,1,0,0,1,1
parameter_1: 3 - Digital input and output: I2S
parameter_2: 1 - Microphone1 (this setting is only for PCM not I2S)
parameter_3: 1 - Selects the earpiece amplifier 1 (this setting is only for PCM not I2S)
parameter_4: 1 - PCM clock (256KHz/512KHz)
parameter_5: 0 - master **** (I tried also slave ****:1)
parameter_6: 0 - frame ****: Short frame
parameter_7: 1 - ext clock I2S master clock will be automatically provided only during audio activity
parameter_8: 1 - Sample rate: 16kHz
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Thank you in advance
Best regards Alan Sabo
Hello,
The connections seem to be correct (based on the module's and mini streamer documentation).
The MCLK is an output pin for both the module and mini streamer. None of them has MCLK input so I think that it's not needed in any configuration between these two devices.
I can't see the .wav files.
Comparing the documentation for mini streamer and module I can see one thing. But I don't rather believe that it matters here. According to the PLS8 hardware description the i2s interface transmits mono voice signals for telephony services while the mini streamer uses 2 channels. On the graph in the HW spec it looks like there is data for the left channel (FSC low) and no data for the right channel (FSC high). But this would rather result only in cutting off one of the stereo channels.
Other thing that I noticed in the mini streamer documentation and might matter here is: "This protocol is not intended to run long cables lengths, but only short Inter-IC, board to board connections." This might be a cause of wrong quality.
Maybe you should also try with some other hardware for comparison.
Regards,
Bartłomiej
Hello Bartłomiej
Thank you very much for your answer and your time. I had the same idea that problem should be that Cinterion use 1 channel audio "mono" and miniSTREAMER has two channels "stereo". It is pity that on miniSTREAMER is not possible set 1channel only 2channels. I wanted upload audio wav file however it is not possible upload wav or zip file. I zipped two audio wav files with zip and changed file extension to JPG. Could you hear this audio files please maybe it will help.
Best regards Alan
Hello Bartłomiej
I uploaded audio wav files to google drive
https://drive.google.com/drive/folders/0Bz_Bp_klwXy-OWVxRkNtcUJnU1E?usp=sharing
Alan
Hello,
Thank you for the files. It sounds really strange.
I've learned that this problem was also reported to the Gemalto support and my colleague is analyzing this also.
We'll let you know when we determine any more details or have additional questions.
We've been testing this successfully some time ago (with some other hardware piece) so there must be a way to get it working.
Best regards,
Bartłomiej
Hello Bartłomiej
Thnak you for help.
best regards
Alan