80 lines
2.5 KiB
Arduino
80 lines
2.5 KiB
Arduino
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/*
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This example generates a square wave based tone at a specified frequency
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and sample rate. Then outputs the data using the I2S interface to a
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MAX08357 I2S Amp Breakout board.
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I2S Circuit:
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* Arduino/Genuino Zero, MKR family and Nano 33 IoT
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* MAX08357:
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* GND connected GND
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* VIN connected 5V
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* LRC connected to pin 0 (Zero) or 3 (MKR), A2 (Nano) or 25 (ESP32)
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* BCLK connected to pin 1 (Zero) or 2 (MKR), A3 (Nano) or 5 (ESP32)
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* DIN connected to pin 9 (Zero) or A6 (MKR), 4 (Nano) or 26 (ESP32)
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DAC Circuit:
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* ESP32 or ESP32-S2
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* Audio amplifier
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- Note:
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- ESP32 has DAC on GPIO pins 25 and 26.
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- ESP32-S2 has DAC on GPIO pins 17 and 18.
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- Connect speaker(s) or headphones.
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created 17 November 2016
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by Sandeep Mistry
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For ESP extended
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Tomas Pilny
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2nd September 2021
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*/
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#include <I2S.h>
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const int frequency = 440; // frequency of square wave in Hz
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const int amplitude = 500; // amplitude of square wave
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const int sampleRate = 8000; // sample rate in Hz
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const int bps = 16;
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const int halfWavelength = (sampleRate / frequency); // half wavelength of square wave
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short sample = amplitude; // current sample value
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int count = 0;
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i2s_mode_t mode = I2S_PHILIPS_MODE; // I2S decoder is needed
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// i2s_mode_t mode = ADC_DAC_MODE; // Audio amplifier is needed
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// Mono channel input
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// This is ESP specific implementation -
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// samples will be automatically copied to both channels inside I2S driver
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// If you want to have true mono output use I2S_PHILIPS_MODE and interlay
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// second channel with 0-value samples.
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// The order of channels is RIGH followed by LEFT
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//i2s_mode_t mode = I2S_RIGHT_JUSTIFIED_MODE; // I2S decoder is needed
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void setup() {
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Serial.begin(115200);
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Serial.println("I2S simple tone");
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// start I2S at the sample rate with 16-bits per sample
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if (!I2S.begin(mode, sampleRate, bps)) {
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Serial.println("Failed to initialize I2S!");
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while (1); // do nothing
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}
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}
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void loop() {
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if (count % halfWavelength == 0 ) {
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// invert the sample every half wavelength count multiple to generate square wave
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sample = -1 * sample;
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}
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if(mode == I2S_PHILIPS_MODE || mode == ADC_DAC_MODE){ // write the same sample twice, once for Right and once for Left channel
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I2S.write(sample); // Right channel
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I2S.write(sample); // Left channel
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}else if(mode == I2S_RIGHT_JUSTIFIED_MODE || mode == I2S_LEFT_JUSTIFIED_MODE){
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// write the same only once - it will be automatically copied to the other channel
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I2S.write(sample);
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}
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// increment the counter for the next sample
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count++;
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}
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