User's Manual

26
Operating the RB540MB for TrueWireless Stereo Sound
The RB540 has optional firmware for True Wireless Stereo sound. This firmware allows the user to
establish a Bluetooth stereo connection between two RB540 Modules and a Bluetooth capable cell
phone. After a Bluetooth connection is established with the phone, then establish a connection
between RB540MB Master and RB540MB Slave. The user can now play music from his phone.
When the RB540MB Master receives the Music from the phone, it will split the sound into two
channels for stereo operation. The RB540MB Master will play one channel and the RB540MB
Slave will play the other channel.
The following will explain how to use the RB540MB switches to control the RB540 module with
the standard TWS firmware.
Connect a speaker and USB cable into both RB540MB boards.
1. Power ON: First we will create a Master RB540. Power on one of the RB540 modules by
plugging in the USB cable and turn on the PSW1.
2. Initiate Pairing with cell phone: Short press SW4 button to enter the Bluetooth discovery mode,
the on-board LED1 should start flashing and a periodic "du" sound can be heard from through
the speaker connected to the Master RB540MB.
Use the cell phone to discover and connect with the Master. The device name to search for is
"TWS v11.003". The LED1 will stay lit after Bluetooth connection is established.
Note: the first RB540 paired to a cell phone is a Master RB540.
3. Initiate Pairing with two RB540: Short press SW2 button on both (Master and Slave) units to
start the pairing process between them. A periodic "du du" sound can be heard through both
speakers and LED2 will be flashing on both units. The first time they pair might take a minute.
This is due to the two Bluetooth modules synchronizing their clocks. Once the pairing process
is complete, the LED2 will stay lit on both RB540MB.
4. Play Music: Use the cell phone to play music. After a short delay, you to hear the music in stereo
through the two speakers. Volume control is available only on cell phone in this firmware.
Note: RB540 Master is SPK_L, and RB540 Slave is SPK_R.
The next time you use the phone to connect, the complete process will only take a couple of seconds.
Use the cell phone to reconnect “TWS v11.003”, the modules will automatically connect to each
other and the music can be played immediately.
Note: Long press 3 seconds on either SW2 or SW4 will trigger a “reset” on RB540. Pairing
information will be cleared in RB540. Due to different cell phone behavior, some cell phone
may be able to reconnect to RB540 after a “reset” because the cell phone still keep the pairing
record with RB540.