01 / Embedded systems

nRF52840 Wireless Audio Link

A one-way audio link between two XIAO nRF52840 boards using Nordic Enhanced ShockBurst (ESB). The prototype accepts a 48 kHz PCM2706 I2S source, packages a lower-rate mono stream for the radio link, and reconstructs I2S output for a PCM5102 DAC.

PCM2706→ I2S→ nRF TX→ ESB→ nRF RX→ I2S→ PCM5102

2 Mbit/s Nordic ESB radio link

48 kHz PCM2706 stereo source

8 kHz 8-bit mono radio payload

System architecture

PCM2706 I2S source → XIAO nRF52840 transmitter → 2 Mbit/s Nordic ESB link → XIAO nRF52840 receiver → PCM5102 DAC.

Signal handling

Converted 48 kHz, 16-bit stereo input to an 8 kHz, 8-bit mono stream before packaging each 20 ms audio block into eight 32-byte packets.

Packet handling

Implemented CRC-16 validation, acknowledgements, retries, sequence checks, and link-loss recovery to detect packet errors and handle interrupted transmission.

Prototype result

Achieved audible playback from the 48 kHz PCM2706 source through the wireless prototype, then isolated distortion and radio-link behavior for continued tuning.

Build evidence

The public repository includes separate transmitter and receiver firmware, diagnostic modes, a versioned packet format, and structurally validated UF2 build artifacts.

The repository build report documents compilation and artifact validation separately from physical hardware testing.