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libraries/audio-tools/examples/examples-stream/streams-memory_raw-i2s/README.md

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+# Digital output via I2S to a external DAC
+
+Somtimes we want to store the sound file in memory. [Audacity](https://www.audacityteam.org/) 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 the example I was just using one channel to save memory!.
+
+Then you can convert the file with xxd into a C file that contains the data in an array. In the Sketch I am using the __MemoryStream class__ which turns the array into a Stream. 
+
+Please note that you must compile this sketch with the __Partition Scheme: Huge App__!
+
+
+### External DAC:
+
+![DAC](https://pschatzmann.github.io/Resources/img/dac.jpeg)
+
+For my tests I am using the 24-bit PCM5102 PCM5102A Stereo DAC Digital-to-analog Converter PLL Voice Module pHAT
+
+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)
+
+

libraries/audio-tools/examples/examples-stream/streams-memory_raw-i2s/streams-memory_raw-i2s.ino

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+/**
+ * @file streams-memory_raw-i2s.ino
+ * @author Phil Schatzmann
+ * @brief Compile with Partition Scheme Hughe APP!
+ * @version 0.1
+ * @date 2021-01-24
+ * 
+ * @copyright Copyright (c) 2021
+ * 
+ */
+#include "AudioTools.h"
+#include "StarWars30.h"
+
+AudioInfo info(22050, 1, 16);
+I2SStream i2s;  // Output to I2S
+MemoryStream music(StarWars30_raw, StarWars30_raw_len);
+StreamCopy copier(i2s, music); // copies sound into i2s
+
+void setup(){
+    Serial.begin(115200);
+    AudioToolsLogger.begin(Serial, AudioToolsLogLevel::Info);
+
+    auto config = i2s.defaultConfig(TX_MODE);
+    config.copyFrom(info);
+    i2s.begin(config);
+}
+
+void loop(){
+    if (!copier.copy()){
+      i2s.end();
+      stop();
+    }
+}