GettingStarted_Arduino.md

Install the Arduino Pico support

Follow the instructions at https://github.com/earlephilhower/arduino-pico

Start Arduino IDE and select the board

Make sure that a CPU frequency of 133MHz might not be sufficient, so try higher clock speeds like 225MHz.

Code examples

Audio DAC

This example will play a 220Hz Square Wave

#include <I2S.h>

// Create the I2S port using a PIO state machine
I2S i2s(OUTPUT);

// GPIO pin numbers
#define pMute 25
#define pDemp 23

const int frequency = 220; // frequency of square wave in Hz
const int amplitude = 500; // amplitude of square wave
const int sampleRate = 48000;

const int halfWavelength = (sampleRate / frequency); // half wavelength of square wave

int16_t sample = amplitude; // current sample value
int count = 0;

void setup() {
  pinMode(PIN_LED0, OUTPUT);
  digitalWrite(PIN_LED0, 1);

  pinMode(pMute, OUTPUT);
  digitalWrite(pMute, HIGH); // unmute codec

  pinMode(pDemp, OUTPUT);
  digitalWrite(pDemp, LOW);

  Serial.begin(115200);

  Serial.println("I2S simple tone");

  i2s.setBCLK(PIN_I2S_BCLK);
  i2s.setDATA(PIN_I2S_DOUT);
  i2s.setBitsPerSample(16);

  // start I2S at the sample rate with 16-bits per sample
  if (!i2s.begin(sampleRate)) {
    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;
  }

  // write the same sample twice, once for left and once for the right channel
  i2s.write(sample);
  i2s.write(sample);

  // increment the counter for the next sample
  count++;

  if(count % 1024 == 0) Serial.println(count);
}

8x 12-Bit on-board ADC

#include "SPI.h"

SPISettings spiSettingsAdc(16000000, MSBFIRST, SPI_MODE2);

void setup()
{
  Serial.begin(115200);
  
  pinMode(PIN_SPI1_SS, OUTPUT);
  SPI1.setTX(PIN_SPI1_MOSI);
  SPI1.setRX(PIN_SPI1_MISO);
  SPI1.setSCK(PIN_SPI1_SCK);
  SPI1.begin();
}

uint16_t readADC(int chan)
{
  SPI.beginTransaction(spiSettingsAdc);
  digitalWrite(PIN_SPI1_SS, LOW);
  uint8_t hi = SPI1.transfer( chan << 3 );
  uint16_t lo = SPI1.transfer( 0 );
  digitalWrite(PIN_SPI1_SS, HIGH);
  SPI.endTransaction();
  return (hi << 8) | lo;
}

void loop()
{
  
  for(int ch=0; ch<8; ch++){
    uint16_t val = readADC(ch);
    Serial.print(val);
    Serial.print(" ");
  }
  Serial.println();
  delay(10); // you can skip the delay.
}

More examples incl. complex ones with a TX callback will follow soon.