Audio Playback and Recording

LinkIt Smart 7688 development board has an I2S interface for audio playback and recording. This is not available on LinkIt Smart 7688 Duo development board. You'll need an audio DAC to convert the I2S to analog sound data.

A simple option is to get a LinkIt Smart 7688 breakout board from Seeed Studio, and use it for audio playback and recording.

The recording function is only supported with firmware v0.9.3 and above. The required breakout board version is LinkIt Smart 7688 breakout v2. For the v1 breakout board, hardware rework is required to enable the recording function.

Setup the board

  1. Attach the LinkIt Smart 7688 development board to the breakout, as shown below: 

  2. Plug an earphone to the audio jack.
  3. Power up the board.
  4. Connect it with a USB drive that contains the audio files.

Audio playback

MP3 playback

To play a MP3 file, use madplay:

# madplay "path_to_your_mp3_file"

WAV playback

To play a WAV file, use aplayas shown below:

# aplay -M "path_to_your_wav_file"  

Audio recording

WAV recording

To record an audio file, use arecord, as shown below: 

# arecord -f cd -t wav -M /Media/USB-A1/my_recording.wav  

For a high bit-rate WAV recording, such as 16bit/44.1k format, record the file to a destination with high I/O speed (e.g. USB drive, SD card, or RAM) instead of the on-board flash. Due to the low writing speed of the on-board flash, users will experience sound jittering and buffer overrun if the recorded file is written to the on-board flash.