BluetoothSerial shows up as audio device on macOS, immediately disconnects

[gohai]

Hardware:

Board: Adafruit ESP32 Feather
Core Installation/update date: April 10 2018
IDE name: Arduino 1.8.5
Flash Frequency: 80MHz
Upload Speed: 921600

Description:

Running the SerialToSerialBT example shows up as an "audio" device on macOS 10.13.4. The device disconnects on its own soon after pairing. Thus, it cannot be used currently. (See screenshot for details.)

[tueddy]

Same here on MacOS 10.13.4
Also no success on iOS 11.3, tested with system-bluetooth and some BT serial apps like Bluefruit, BluTerm, LightBlue and JBWave.

Sorry but the BTSerial demo is simply not functional?

[copercini]

oh, the Bluetooth service class is hardcoded as a speaker on IDF: https://github.com/espressif/esp-idf/blob/f620a3c4f35cb715e5b6e37e8556ec2278628660/components/bt/bluedroid/include/bt_target.h#L578

[beegee-tokyo]

ESP32 bluetooth is showing as speakers on Android as well, but Bluetooth Serial is working fine as shown in my little tutorial. Cannot not test on MAC or iOS though.

[gohai]

@copercini This define appears to set the default via p_bta_dm_cfg, but shouldn't it be possible to re-configure this e.g. through BTM_SecAddDevice or BTM_SetDeviceClass?

[gohai]

I looked at the output of macOS' Console application while I attempted to connect to the device: the process bluetoothaudiod attempts a couple of times to creates an audio device, realizes that No protocols known for device or services are nil, and finally gives up, at which point bluetoothd removes the device. So this confirms the suspicion that the device class plays a role here.

[gohai]

@me-no-dev The necessary functionality appears to have been added in espressif/esp-idf@789edc0. Would it be possible to update IDF to at least this commit?

[lbernstone]

You can update the code yourself if you want to test. #1142

[gohai]

@lbernstone Thank you for the pointer. I just tried this, following your instructions - would you mind helping me a bit further?

First, I found the idf-update branch in this repository. Unfortunately it looks like its IDF is a few versions behind espressif/esp-idf@789edc0 still.

Next I tried compiling blink with the following combinations:

• espressif/esp-idf@789edc0 (first revision I can use) and 0cd15b4 (idf-update head): fails with 'sdmmc_host_io_int_enable' was not declared in this scope
• espressif/esp-idf@789edc0 (first revision I can use) and 89859f7 (master): succeeded
• espressif/esp-idf@9a55b42 (master) and 0cd15b4 (idf-update head): succeeded
• espressif/esp-idf@9a55b42 (master) and 89859f7 (master): fails with gatt_api.h: No such file or directory

How do I go from here? Which of the above would you use? Should copying libesp32.a (and the specific header file that I need) be enough? Would you suggest I then use this on top of the arduino-esp32 master or idf-update branch?

Thanks in advance.

[copercini]

Same issue solved: https://www.esp32.com/viewtopic.php?f=13&t=6099

Now the only problem is with the outdated IDF version of this core

[gohai]

Here is a recompiled IDF with the default COD set to the changed values, if anyone else needs this as a workaround till this repo updates IDF again: https://github.com/gohai/arduino-esp32/commit/2c772325ffe94173f1674583c6e9cafb07826df0

[copercini]

Fixed in 901a341

Thanks @gohai !