arduino-audio-tools/examples/examples-stream/streams-url_raw-i2s

Stream URL to I2S external DAC

We are reading a raw audio file from the Intenet and write the data to the I2S interface. The audio file must be available using 16 bit integers with 2 channels. I used a sampling rate of 8000.

Audacity might help you out here: export with the file name audio.raw as RAW signed 16 bit PCM and copy it to the SD card. In my example I was using the file audio.raw.

External DAC:

I am just using the default pins defined by the framework. However I could change them with the help of the config object. The mute pin can be defined in the constructor of the I2SStream - by not defining anything we use the default which is GPIO23

DAC	ESP32
VCC	5V
GND	GND
BCK	BCK (GPIO14)
DIN	OUT (GPIO22)
LCK	BCK (GPIO15)
FMT	GND
XMT	3V (or another GPIO PIN which is set to high)

• DMP - De-emphasis control for 44.1kHz sampling rate(1): Off (Low) / On (High)
• FLT - Filter select : Normal latency (Low) / Low latency (High)
• SCL - System clock input (probably SCL on your board).
• FMT - Audio format selection : I2S (Low) / Left justified (High)
• XMT - Soft mute control(1): Soft mute (Low) / soft un-mute (High)