Extended SimpleTone example with DAC settings

Author: PilnyTomas

libraries/I2S/examples/SimpleTone/SimpleTone.ino

@@ -3,7 +3,7 @@
  and sample rate. Then outputs the data using the I2S interface to a
  MAX08357 I2S Amp Breakout board.
 
- Circuit:
+ I2S Circuit:
  * Arduino/Genuino Zero, MKR family and Nano 33 IoT
  * MAX08357:
    * GND connected GND
@@ -12,8 +12,19 @@
    * BCLK connected to pin 1 (Zero) or 2 (MKR), A3 (Nano) or 5 (ESP32)
    * DIN connected to pin 9 (Zero) or A6 (MKR), 4 (Nano) or 26 (ESP32)
 
+ DAC Circuit:
+ * ESP32 or ESP32-S2
+ * Audio amplifier
+   - Note:
+     - ESP32 has DAC on GPIO pins 25 and 26.
+     - ESP32-S2 has DAC on GPIO pins 17 and 18.
+  - Connect speaker(s) or headphones.
+
  created 17 November 2016
  by Sandeep Mistry
+ For ESP extended by
+ Tomas Pilny
+ 2nd September 2021
  */
 
 #include <I2S.h>
@@ -27,12 +38,16 @@ const int halfWavelength = (sampleRate / frequency); // half wavelength of squar
 short sample = amplitude; // current sample value
 int count = 0;
 
+//i2s_mode_t mode = I2S_PHILIPS_MODE;
+i2s_mode_t mode = I2S_ADC_DAC;
+
+
 void setup() {
   Serial.begin(115200);
   Serial.println("I2S simple tone");
 
   // start I2S at the sample rate with 16-bits per sample
-  if (!I2S.begin(I2S_PHILIPS_MODE, sampleRate, bps)) {
+  if (!I2S.begin(mode, sampleRate, bps)) {
     Serial.println("Failed to initialize I2S!");
     while (1); // do nothing
   }
@@ -45,9 +60,11 @@ void loop() {
       sample = -1 * sample;
     }
 
-    // write the same sample twice, once for left and once for the right channel
-    I2S.write(sample);
     I2S.write(sample);
+    // write the same sample twice, once for left and once for the right channel
+    if(mode == I2S_PHILIPS_MODE){
+      I2S.write(sample);
+    }
 
     // increment the counter for the next sample
     count++;