3.3.7

libraries/ESP_I2S/examples/Simple_tone/Simple_tone.ino

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+/*
+ This example generates a square wave based tone at a specified frequency
+ and sample rate. Then outputs the data using the I2S interface to a
+ MAX08357 I2S Amp Breakout board.
+ I2S Circuit:
+ * Arduino/Genuino Zero, MKR family and Nano 33 IoT
+ * MAX08357:
+   * GND connected GND
+   * VIN connected 5V
+   * LRC connected to pin 0 (Zero) or 3 (MKR), A2 (Nano) or 25 (ESP32)
+   * 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
+ Tomas Pilny
+ 2nd September 2021
+ Lucas Saavedra Vaz (lucasssvaz)
+ 22nd December 2023
+ anon
+ 10nd February 2025
+ */
+
+#include <ESP_I2S.h>
+
+// The GPIO pins are not fixed, most other pins could be used for the I2S function.
+#define I2S_LRC  25
+#define I2S_BCLK 5
+#define I2S_DIN  26
+
+const int frequency = 440;    // frequency of square wave in Hz
+const int amplitude = 500;    // amplitude of square wave
+const int sampleRate = 8000;  // sample rate in Hz
+
+i2s_data_bit_width_t bps = I2S_DATA_BIT_WIDTH_16BIT;
+i2s_mode_t mode = I2S_MODE_STD;
+i2s_slot_mode_t slot = I2S_SLOT_MODE_STEREO;
+
+const unsigned int halfWavelength = sampleRate / frequency / 2;  // half wavelength of square wave
+
+int32_t sample = amplitude;  // current sample value
+unsigned int count = 0;
+
+I2SClass i2s;
+
+void setup() {
+  Serial.begin(115200);
+  Serial.println("I2S simple tone");
+
+  i2s.setPins(I2S_BCLK, I2S_LRC, I2S_DIN);
+
+  // start I2S at the sample rate with 16-bits per sample
+  if (!i2s.begin(mode, sampleRate, bps, slot)) {
+    Serial.println("Failed to initialize I2S!");
+    while (1);  // do nothing
+  }
+}
+
+void loop() {
+  if (count % halfWavelength == 0) {
+    // invert the sample every half wavelength count multiple to generate square wave
+    sample = -1 * sample;
+  }
+
+  // Left channel, the low 8 bits then high 8 bits
+  i2s.write(sample);
+  i2s.write(sample >> 8);
+
+  // Right channel, the low 8 bits then high 8 bits
+  i2s.write(sample);
+  i2s.write(sample >> 8);
+
+  // increment the counter for the next sample
+  count++;
+}

libraries/ESP_I2S/examples/Simple_tone/ci.yml

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+requires:
+  - CONFIG_SOC_I2S_SUPPORTED=y