Problems with BK8000L audio Bluetooth module.

[Les Jones]

I have recently bought a BK8000L audio Bluetooth module. I can't communicate with it via the serial port to configure it using AT commands. The RX and TX pins seem to be being held low. (I would expect the TX pin to be at about + 3 volts with nothing connected to it.) When I connect an FTDI FT232RL (USB to serial module.) to the TX from the FTDI module is pulled down to about 1.4 volts by the RX pin of the bluetooth module. (Before it is connected the FTDI TX line is at about +3.3 volts. I had tried sending AT commands at baud rates from 1200 bauds to 115200 bauds before I realised that the RX and TX pins were being held low without any response. I can pair it with my Nexus 7 and it works in the receive mode but I cannot pair it with Bluetooth headphones to use it in the transmit mode. (Which is why I bought it.) Has any other forum member had any success in using the AT commands with this type of module. I have never had a problem with AT commands with Bluetooth HC-05 or HC-06.

Les.

 

[Pommie]

Hi Les,

Couldn't find much info on this module but did find a page with useful diagrams and baudrate etc. See https://www.electrodragon.com/w/BK8000L

Mike.

 

[Les Jones]

Hi Mike,
Thanks for the link. I have that information and all the information I found on the web seems to be based on it. There are some Youtube videos showing AT commands being used and the device being used in the transmit mode but that was with a mobile phone so the pairing would have been initiated from the mobile phone. One thing that does not work as expected is the Aux_det input. (Pin 18) When that is held low (The state to select the Aux inputs) the device does not enter pairing modes with the two LEDs flashing. (The red LED is permanently on.) I have a suspicion that the device is being shipped with different versions of the firmware. I have not seen any information about different firmware versions or how to reload firmware.

Les.