🔶 PCM5102 I²S DAC Decoder GY-PCM5102 — High-Fidelity I2S Audio Player Module for Raspberry Pi & ESP32

📦 Overview

The GY-PCM5102 is a compact I²S audio DAC module using the PCM5102 chip to convert digital I²S audio into clean analogue stereo output. Designed for Raspberry Pi, ESP32 and other I²S-capable hosts, this board delivers improved analogue audio quality compared to on-board audio outputs, and is ideal for DIY Hi-Fi players, network audio streamers and audio experiments.

✅ Key Benefits

• High-fidelity PCM5102 stereo DAC — low noise, good SNR
• Simple I²S connection (BCLK / LRCLK / DATA) to Raspberry Pi or ESP32
• Compact breakout board suitable for custom audio enclosures
• Works with ALSA, Volumio, RuneAudio, Mopidy and other players

⚙️ Typical Specifications

• DAC IC: PCM5102 (stereo)
• Interface: I²S (BCLK / LRCLK / DATA)
• Output: Analogue stereo line-level (L / R)
• Operating Voltage: Module-specific (check photos) — typically 3.3V or 5V
• Compatible With: Raspberry Pi, ESP32, other I²S masters

🔌 Wiring — Example (Raspberry Pi & ESP32)

PCM5102 Module Pin      Raspberry Pi (40-pin header)
------------------      -----------------------------
GND                     GND (Pin 6, 9, 14, etc.)
VCC                     5V or 3.3V (see module spec)  <-- CHECK MODULE BEFORE POWERING
BCLK (Bit Clock)        PCM_CLK / GPIO18 (Pin 12)
LRCLK (Word Clock)      PCM_FS  / GPIO19 (Pin 35)
DIN / DATA (SD)         PCM_DIN / GPIO21 (Pin 40)     <-- Pi outputs data on this pin
Analog L / R            RCA / header (module dependent)

IMPORTANT: Confirm VCC level on your module before connecting power. Wrong voltage can damage the board.

⚡ Quick Raspberry Pi Setup

1. Wire the PCM5102 to the Pi as shown above.
2. Enable I²S on the Pi (set dtparam=i2s=on in /boot/config.txt or use raspi-config).
3. Install ALSA utilities: sudo apt update && sudo apt install -y alsa-utils.
4. Use aplay -l to list audio devices and play a test WAV with aplay -D plughw:0,0 sample.wav (device id may vary).

🧩 ESP32 I²S Test Example (Collapsible)

Use this Arduino-style ESP32 sketch to test the PCM5102 by playing a 440 Hz sine tone over I²S.

// ESP32 — I2S sine test for PCM5102 (Arduino framework)
// Connect ESP32 I2S pins to PCM5102 (check your module pin labels).
// Example pin mapping (change to your wiring):
//  BCLK  -> GPIO26
//  LRCLK -> GPIO25
//  DOUT  -> GPIO22
//
// This sketch generates a 440 Hz sine wave (stereo, 16-bit, 44.1kHz)
// and outputs continuously via I2S to the DAC (PCM5102).

#include <driver/i2s.h>
#include <math.h>

#define I2S_NUM           I2S_NUM_0
#define SAMPLE_RATE       44100
#define SINE_FREQ         440.0f
#define PI 3.14159265f

const int I2S_BCLK_PIN  = 26;
const int I2S_LRCK_PIN  = 25;
const int I2S_DATA_PIN  = 22;
const int BUFFER_SAMPLES = 512;
int16_t i2s_buffer[BUFFER_SAMPLES * 2];

void setupI2S() {
  i2s_config_t i2s_config = {
    .mode = (i2s_mode_t)(I2S_MODE_MASTER | I2S_MODE_TX),
    .sample_rate = SAMPLE_RATE,
    .bits_per_sample = I2S_BITS_PER_SAMPLE_16BIT,
    .channel_format = I2S_CHANNEL_FMT_RIGHT_LEFT,
    .communication_format = I2S_COMM_FORMAT_STAND_I2S,
    .intr_alloc_flags = 0,
    .dma_buf_count = 4,
    .dma_buf_len = BUFFER_SAMPLES,
    .use_apll = false,
    .tx_desc_auto_clear = true
  };

  i2s_pin_config_t pin_config = {
    .bck_io_num = I2S_BCLK_PIN,
    .ws_io_num = I2S_LRCK_PIN,
    .data_out_num = I2S_DATA_PIN,
    .data_in_num = I2S_PIN_NO_CHANGE
  };

  i2s_driver_install(I2S_NUM, &i2s_config, 0, NULL);
  i2s_set_pin(I2S_NUM, &pin_config);
}

void fill_sine_buffer(float frequency) {
  const float amplitude = 0.7f * 32767.0f;
  for (int i = 0; i < BUFFER_SAMPLES; ++i) {
    float sample = amplitude * sinf(2.0f * PI * frequency * ((float)i / (float)SAMPLE_RATE));
    int16_t s = (int16_t)sample;
    i2s_buffer[2 * i]     = s;
    i2s_buffer[2 * i + 1] = s;
  }
}

void setup() {
  Serial.begin(115200);
  delay(200);
  Serial.println("ESP32 I2S PCM5102 sine test starting...");
  setupI2S();
  fill_sine_buffer(SINE_FREQ);
}

void loop() {
  size_t bytes_written = 0;
  size_t bytes_to_write = sizeof(i2s_buffer);
  esp_err_t err = i2s_write(I2S_NUM, (const char*)i2s_buffer, bytes_to_write, &bytes_written, portMAX_DELAY);
  if (err != ESP_OK) {
    Serial.printf("i2s_write error: %d\n", err);
    delay(200);
  }
}
  

🧩 Arduino Quick Test (Collapsible)

// Note: For Raspberry Pi use ALSA/overlays; for Arduino-based MCUs with I2S support (ESP32 above) use the provided ESP32 example.
// To play stored audio files you need an audio decoder (e.g., WAV decode) and a file system (SPIFFS/SD) or streaming source.
  

💡 Possible Uses

• Raspberry Pi Hi-Fi DAC upgrade for cleaner analogue audio
• Network audio players (Volumio / RuneAudio / Moode)
• Custom audio front-end for headphone amps or powered speakers
• Embedded I²S learning projects using ESP32 or SBCs

📦 Package Includes

• 1 × GY-PCM5102 I²S DAC Module (PCM5102)

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