Add PlayAACSD example (#48)

examples/PlayAACSD/PlayAACSD.ino

@@ -0,0 +1,102 @@
+
+// PlayAACSD - Dhiru Kholia <dhiru@openwall.com>
+// Released to the public domain February 2025.
+//
+// Plays an AAC file (named demo.aac) from the SD card using the CJMCU-4344
+// DAC. This program should help in getting MCLK-enabled DACs to work well.
+// This example also works well with the ESHINE CJC4334 DAC.
+//
+// This example should also work for the Pico-Audio Rev2.1 DAC which uses
+// the CS4344 DAC chip as well.
+//
+// This example was only tested on a Raspberry Pi Pico 2 board.
+//
+// Based on PlayAACROM + NotSoSimpleMP3Shuffle examples by Earle F. Philhower, III
+
+#include <BackgroundAudioAAC.h>
+#ifdef ESP32
+#include <ESP32I2SAudio.h>
+ESP32I2SAudio audio(4, 5, 6);  // BCLK, LRCLK, DOUT (,MCLK), untested
+#else
+#include <I2S.h>
+I2S audio(OUTPUT);
+#endif
+#include <SD.h>
+
+// CJMCU-4344 DAC pinout
+#define pMCLK 26
+#define pLRCLK 27
+#define pDOUT 29
+
+#define MCLK_MUL 64  // depends on the audio hardware
+
+#define FILENAME_TO_PLAY "demo.aac"
+File f;
+uint8_t filebuff[512];
+BackgroundAudioAAC BMP(audio);
+
+// SD card chip select
+int chipSelect = 5;
+
+void fail() {
+  while (1) {
+    delay(1000);
+#ifdef ESP32
+    ESP.restart();
+#else
+    rp2040.reboot();
+#endif
+  }
+}
+
+void setup() {
+  Serial.begin(115200);
+  Serial.println("PlayAACSD demo program");
+
+#ifdef ARDUINO_ARCH_RP2040
+  audio.setBCLK(pLRCLK);
+  audio.setDATA(pDOUT);
+  audio.setMCLK(pMCLK);         // must be run before setFrequency() and i2s.begin()
+  audio.setMCLKmult(MCLK_MUL);  // also before i2s.begin()
+  // In swapClocks mode the setBCLK call actually sets LRCLK
+  audio.swapClocks();  // required for CJMCU-4344 DAC
+
+  // Follows https://github.com/elehobica/RPi_Pico_WAV_Player?tab=readme-ov-file#sd-card-interface
+  SPI.setSCK(2);
+  SPI.setTX(3);
+  SPI.setRX(4);
+  SPI.setCS(chipSelect);
+  SPI.begin(false);
+#endif
+
+  // Initialize the SD card
+  bool sdInitialized = false;
+#ifdef ESP32
+  sdInitialized = SD.begin(chipSelect);
+#else
+  sdInitialized = SD.begin(chipSelect);
+#endif
+
+  if (!sdInitialized) {
+    Serial.println("initialization failed!");
+    fail();
+  }
+
+  f = SD.open(FILENAME_TO_PLAY);
+  if (!f) {
+    Serial.printf("Unable to open %s", FILENAME_TO_PLAY);
+    fail();
+  }
+
+  BMP.begin();
+}
+
+void loop() {
+  while (f && BMP.availableForWrite() > 512) {
+    int len = f.read(filebuff, 512);
+    BMP.write(filebuff, len);
+    if (len != 512) {
+      f.close();
+    }
+  }
+}