User interface

All nRF5340 Audio applications implement the same, simple user interface based on the available PCB elements of the nRF5340 Audio development kit. You can control the application using predefined switches and buttons while the LEDs display information.

Some user interface options are only valid for some nRF5340 Audio applications.

Switches

The application uses the following switches on the supported development kit:

Switch

Function

Applications

POWER

Turns the development kit on or off.

All

DEBUG ENABLE

Turns on or off power for debug features. This switch is used for accurate power and current measurements.

All

Buttons

The application uses the following buttons on the supported development kit:

Button

Function

Applications

VOL-

Long-pressed during startup: Changes the headset to the left channel one.

Pressed on the headset or the CIS gateway during playback: Turns the playback volume down.

VOL+

Long-pressed during startup: Changes the headset to the right channel one.

Pressed on the headset or the CIS gateway during playback: Turns the playback volume up.

PLAY/PAUSE

Starts or pauses the playback of the stream or listening to the stream.

All

BTN 4

Long-pressed during startup: Turns on the DFU mode, if the device is configured for it.

All

Pressed on the gateway during playback: Toggles between the normal audio stream and different test tones generated on the device. Use this tone to check the synchronization of headsets.

Pressed on the gateway during playback multiple times: Changes the test tone frequency. The available values are 1000 Hz, 2000 Hz, and 4000 Hz.

Pressed on a BIS headset during playback: Change stream (different BIS), if more than one is available.

nRF5340 Audio: Broadcast sink

BTN 5

Long-pressed during startup: Clears the previously stored bonding information.

Pressed during playback: Mutes the playback volume.

Pressed on a BIS headset during playback: Change the gateway, if more than one is available.

nRF5340 Audio: Broadcast sink

RESET

Resets the device to the originally programmed settings. This reverts any changes made during testing, for example the channel switches with VOL buttons.

All

LEDs

To indicate the tasks performed, the application uses the LED behavior described in the following table:

LED

Indication

Applications

LED1

Off - No Bluetooth connection.

All

Solid blue on the CIS gateway and headset: Kits have connected.

Solid blue on the BIS headset: Kits have found a broadcasting stream.

nRF5340 Audio: Broadcast sink

Blinking blue on headset: Kits have started streaming audio (BIS and CIS modes).

Blinking blue on the CIS gateway: Kit is streaming to a headset.

nRF5340 Audio: Unicast client

Blinking blue on the BIS gateway: Kit has started broadcasting audio.

nRF5340 Audio: Broadcast source

LED2

Off - Sync not achieved.

All

Solid green - Sync achieved (both drift and presentation compensation are in the LOCKED state).

LED3

Blinking green - The nRF5340 Audio DK application core is running.

All

CODEC

Off - No configuration loaded to the onboard hardware codec.

All

Solid green - Hardware codec configuration loaded.

All

RGB

(bottom side LEDs around the center opening)

Solid green - The device is programmed as the gateway.

Solid blue - The device is programmed as the left headset.

Solid magenta - The device is programmed as the right headset.

Solid yellow - The device is programmed with factory firmware. It must be re-programmed as gateway or headset.

All

Solid red (debug mode) - Fault in the application core has occurred. See UART log for details and use the RESET button to reset the device. In the release mode, the device resets automatically with no indication on LED or UART.

All

ERR

PMIC error or a charging error (or both). Also turns on when charging the battery exceeds seven hours, since the PMIC has a protection timeout, which stops the charging.

All

CHG

Off - Charge completed or no battery connected.

All

Solid yellow - Charging in progress.

OB/EXT

Off - No 3.3 V power available.

All

Solid green - On-board hardware codec selected.

Solid yellow - External hardware codec selected. This LED turns solid yellow also when the devices are reset, for the time then pins are floating.

FTDI SPI

Off - No data is written to the hardware codec using SPI.

All

Yellow - The same SPI is used for both the hardware codec and the SD card. When this LED is yellow, the shared SPI is used by the FTDI to write data to the hardware codec.

IFMCU (bottom side)

Off - No PC connection available.

All

Solid green - Connected to PC.

Rapid green flash - USB enumeration failed.

HUB (bottom side)

Off - No PC connection available.

All

Green - Standard USB hub operation.