How to play music over PCM SCO on imx8 Yocto

[jimi_lin]

HI

I'm trying to bring up the bluetooth SCO voice over PCM.

I had create a sound card for PCM(SAI2) on IMX8. (SAI2 PCM connect to BT chip)

And I can get the waveform while "aplay -D plughw:3,0 test.wav" (bluetooth sound card is 3) on SAI2.

But how do I play the music over SCO PCM to BT headset?

I'm using Yocto system and the version is "i.MX Linux Yocto Project BSP 5.4.3_1.0.0 Release".

And the bluez version is "bluetoothctl: 5.50".

Thanks

[hellochasex]

What's great about music and klingeltöne can all be found easily. Thank you for these interesting sharing

[jimi_lin]

HI igorpadykov

Thanks for your replay.

According to linki.MX8M EVK Bluetooth HSP (SCO) audio , it seems that there is no way to play SCO audio over PCM on bluetz 5.0?

Is it right? Or?

Thanks

[igorpadykov]

I think right, in general nxp official documentation on below link

(Release Notes, Linux Manual) does not mention it

i.MX Software and Development Tools | NXP 

Best regards
igor

[jimi_lin]

HI igorpadykov

We change the OS to android.

And we use tinyplay to play .wav file to PCM interface(SAI2).

We can see the waveform on the scope, there is clk, sync and output data(TX).

Then we set the BT module to PCM loopback mode.

After set the BT module to PCM loopback mode, we can see the input data on PCM RX.

But when we use tinycap to record the RX data, we just got the .wav file header with dummy data(0).

Did I miss any setting on the audio driver or device tree. I can provide the partial code if you need it for debug.

Thanks

[igorpadykov]

I think one can test  PCM loopback mode using only SAI2,

connect its output to input, to narrow down issue if it is caused by

BT chip or i.MX.

Best regards
igo

[igorpadykov]

Hi Jimi

wifi/bluetooth documenation can be found on:

wireless.murata.com/eng/products/rf-modules-1/wi-fi-bluetooth-for-freescale-i-mx.html

and may be useful to look on

i.MX8M EVK Bluetooth HSP (SCO) audio 

also for SCO PCM bluetooth special firmware may be required as mentioned on vendor portal

Murata BCM4339 ZP Bluetooth /Wifi Module - PCM ... | Cypress Developer Community 

Best regards
igor
-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------