Bluetooth SDK

[MaCh_4826131]

Hi,

I have a microphone connected to my CYW920819 board via i2s.

Unfortunately I am unable to get it to stream to my bt headphones via a2dp (is it even possible?)

I am using the watch example for this board and followed the blog below to route i2s.

https://community.cypress.com/t5/Resource-Library/PCM-I2S-Clock-setting-in-CYW20706/ta-p/246335?emcs...

Could it be a codec issue/sampling rate issue?

Any help would be greatly appreciated.

Thanks in advance!

[SheetalJ]

Hi @MaCh_4826131 ,

Audio over I2S is supported by CYW20819 using SBC codec. However, it only supports upto 16kHz frequency.  This is mentioned in datasheet section 7.11 I2S Interface- 

The clock rate in master mode is as follows:
■ 16 kHz × 16 bits per frame = 256 kHz

Please note that CYW20819 can only be used in audio source mode. A note clarifying this is mentioned in datasheet- Only audio source (other than SCO) use cases are supported on CYW20819.

[MaCh_4826131]

Thank you for your reply!

I have used   wiced_audio_start(WICED_FALSE, AUDIO_ROUTE_I2S, lcid, &av_app_cb.sbc_caps_configured);

and have even tried configuring the GPIO pins using  wiced_hal_gpio_select_function(WICED_P12,WICED_PCM_CLK_I2S_CLK);

However i am unable to listen to any input from the microphone still using a2dp on my bt headphones. Is there a step I am missing?

Thanks!

P.S. I have tried putting it in master mode by setting wiced_audio_start(WICED_TRUE, AUDIO_ROUTE_I2S, lcid, &av_app_cb.sbc_caps_configured);

but I am unable to get a clock reading from the pinout on an oscilloscope. 

[SheetalJ]

Are you able to test watch example successfully? It uses audio over I2S only right. Can you check the implementation there once?

[MaCh_4826131]

Yes I tested the watch example, however, i2s input is blanked out. I found out that CYW9BT_Audio is not defined and therefore does not include wiced_audio_manager.h
Could this be the problem? I have reinstalled the audio library using library manager but it seems to still not be included in the project file. 
Do I need to install wiced_audio_manager.h somehow ?

[SheetalJ · Accepted solution]

Hi @MaCh_4826131 ,

Apparently I2S input feature on watch CE is supported only on CYW20721 platform. It is not possible to receive input using a microphone via a codec on CYW20819 over I2S.