WL1801MOD: BT Audio

Marvin Gasis Arcangel

Part Number: WL1801MOD
Other Parts Discussed in Thread: CC2564C,

Hi Team,

Can you please help with this inquiry from customer:

"I have a WL radio module connected to a microcontroller. When i connect my smartphone and headset via bluetooth to the WL module i see two different behaviour.

1. When i streaming music from my smartphone i can see the audio streaming come out from HCI interface and i can also decode it into a wav file. In this case i don't understand if the audio that came out from HCI interface is kind of "mirror" signal that travel inside the WL module. In other words is it possible that the audio stream goes from my smartphone to WL module and then to headset without going into the microcontroller?

2. When i make a phone call i can see that something happen in BT_AUD_IN, BT_AUD_OUT, BT_AUD_FSYNC and BT_AUD_CLK (those signals remains low in the previous point). Is possible that AUD_IN and AUD_OUT are shorted in order to transfer the voice call from smartphone to headset?

Is there a document or kind of guide to understand the BT_AUD interface and also the HCI interface in details?"

Thank you in advance.

Regards,

Marvin

over 1 year ago

0 Jacob B. over 1 year ago

TI__Genius 13052 points

Hi Marvin,

1. You have two options to route the audio paths from the controller: forward to host over HCI (using UART) or to a codec through a PCM interface. Here is a picture from the CC2564C that also applies to the WL1801MOD:

Is there a reason you don't connect the phone directly to the headset?

2. Those signals are used in the PCM interface. I am not familiar with the lines toggling, I would have to investigate. I'm also sharing some documents that may be helpful:

CC256x Audio Source User Guide - Texas Instruments Wiki.pdf

CC256x TI Bluetooth Stack HFPDemo App - Texas Instruments Wiki.pdf

CC256x Advanced Voice and Audio Features - Texas Instruments Wiki.pdf

CC256x Audio Sink Quick Start User Guide - Texas Instruments Wiki.pdf

Thanks,
Jacob

0 Marvin Gasis Arcangel over 1 year ago in reply to Jacob B.

TI__Expert 8940 points

Hi Jacob,

Thank you for the response.

Jacob B. said:
Is there a reason you don't connect the phone directly to the headset?

The customer has another interface that allows them to control the audio streaming and get some information about media.

According to Figure 6-15, the are only 2 ways to route audio using WL18MOD: using PCM and via HCI. Can you confirm if the 3rd scenario is not possible? (please see attached)

options.zip

Thank you.

Regards,

Marvin

0 Jacob B. over 1 year ago in reply to Marvin Gasis Arcangel

TI__Genius 13052 points

Hey Marvin,

I understand your question. Scenario 3 is theoretically possible but TI does not support this functionality. Scenario 2 would work well for a microprocessor, but I see you are using a microcontroller.

Thanks,
Jacob

0 Marvin Gasis Arcangel over 1 year ago in reply to Jacob B.

TI__Expert 8940 points

Hi Jacob,

Thank you for the response. If they decide to work with scenario 2, can you recommend a microprocessor that is readily available and easy to use for this application?

Thanks!

Regards,

Marvin

0 Jacob B. over 1 year ago in reply to Marvin Gasis Arcangel

TI__Genius 13052 points

Hi Marvin,

We don't have a WL8 pairing with a microcontroller. Can they use an MPU? That's what we recommend for WL8.

Best,
Jacob

0 Marvin Gasis Arcangel over 1 year ago in reply to Jacob B.

TI__Expert 8940 points

HI Jacob,

I have a follow up question:

Jacob B. said:
Scenario 3 is theoretically possible but TI does not support this functionality

Does this mean that there is a way to do this using MCU? We just don't support it in terms of doc/source code?

Jacob B. said:
Can they use an MPU?

Can you recommend an MPU that works best and have supporting documents for this kind of application?

Regards,

Marvin

+1 Jacob B. over 1 year ago in reply to Marvin Gasis Arcangel

TI__Genius 13052 points

Hey Marvin,

Yes, it is possible but we have no supporting documentation or knowledge base for doing so.

I recommend the Sitara AM335x platform, but any Linux MPU would suffice.

Best,

Jacob

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WL1801MOD: BT Audio