I apologize if this question is too vague, but I only have a basic knowledge of embedded systems and I know very little about bluetooth.

I am researching for a project in which I want to use a BM70 or BM71 module to act as a source using A2DP to stream audio to a bluetooth speaker. I want to use the BM70/71 in manual mode using a host MCU that controls the BM70/71 using UART. I've read the user manual for BM70/71 and I think I understand how I would discover and establish a connection with another bluetooth device. I've also read the A2DP spec and it seems like (though I'm not sure) I need to establish an L2CAP channel to send the A2DP messages between the devices.

I can't figure out how I can control the BM70/71 to establish the proper connection with the bluetooth speaker in order to send the A2DP commands.

I'm not looking for a complete answer, but just something to push me in the right direction, as I don't know what to search for at this point. I've searched for BM70/71 and L2CAP together but there seems to be nothing out there.


  • \$\begingroup\$ Start from p7... \$\endgroup\$ – Tony Stewart EE75 Feb 23 at 3:56
  • \$\begingroup\$ Could you please explain? What is p7? \$\endgroup\$ – chuck1 Feb 23 at 4:21
  • \$\begingroup\$ Page 7 of the BM70 manual \$\endgroup\$ – Tony Stewart EE75 Feb 23 at 4:40

The BM70 chip is a Bluetooth Low Energy (BLE) module. As far as I know, BLE is not meant for streaming applications. These posts suggest that A2DP and BLE are not compatible: https://stackoverflow.com/questions/22141569/how-are-you-able-to-get-an-a2dp-bluetooth-profile-to-work-using-bluetooth-4-0-b

Does Bluetooth LE stack supports A2DP profile?

  • \$\begingroup\$ Thank you! I did not realize that BLE could not do streaming. I need to look for a different bluetooth module \$\endgroup\$ – chuck1 Feb 23 at 17:56

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