audio from sd

firmware/platformio.ini

@@ -13,7 +13,5 @@ platform = raspberrypi
 board = pico
 framework = arduino
 lib_deps =
-  fastled/FastLED@^3.6.0
-  ; arduino-libraries/SD@^1.2.4
   khoih-prog/RP2040_SD@^1.0.1
 

firmware/scripts/audio_convert.py

@@ -55,3 +55,10 @@ with open("src/audio_sample.h", "w") as f:
     f.write(m68code)
 
 print("done!")
+
+print("writing blob...")
+
+with open("audio/audio.bin", "wb") as f:
+    f.write(bytes(normalized))
+
+print("done!")

firmware/src/audio.cpp

@@ -3,13 +3,21 @@
 #include "hardware/pwm.h"  // pwm
 #include "hardware/sync.h" // wait for interrupt
 #include "hardware/gpio.h"
+#include "audio.h"
 
-#include "audio_sample.h"
+// #include "audio_sample.h"
 
 // Adapted from https://github.com/rgrosset/pico-pwm-audio
 
 #define AUDIO_PIN 23
-int wav_position = 0;
+
+#define MAX_PWM_POS (BUFFER_LEN << 3)
+
+uint8_t wav_buffer_0[BUFFER_LEN] = {0};
+uint8_t wav_buffer_1[BUFFER_LEN] = {0};
+bool wav_buffer1_active = false;
+volatile bool next_buffer_requested = false; // horrible, use some interrupt-based solution or at least locks or whatever
+uint32_t pwm_position = 0;
 
 /*
  * PWM Interrupt Handler which outputs PWM level and advances the
@@ -21,21 +29,23 @@ int wav_position = 0;
  */
 void pwm_interrupt_handler() {
     pwm_clear_irq(pwm_gpio_to_slice_num(AUDIO_PIN));
-    if (wav_position < (WAV_DATA_LENGTH<<3) - 1) {
+    if (pwm_position < MAX_PWM_POS - 1) {
+        auto wav_buffer = wav_buffer1_active ? wav_buffer_1 : wav_buffer_0;
         // set pwm level
         // allow the pwm value to repeat for 8 cycles this is >>3
-        pwm_set_gpio_level(AUDIO_PIN, WAV_DATA[wav_position>>3]);
-        wav_position++;
+        pwm_set_gpio_level(AUDIO_PIN, wav_buffer[pwm_position>>3]);
+        pwm_position++;
     } else {
-        // reset to start
-        wav_position = 0;
+        // reset to start, flip to other buffer
+        pwm_position = 0;
+        next_buffer_requested = true;
+        wav_buffer1_active = !wav_buffer1_active;
     }
 }
 
 // 11 KHz is fine for speech. Phone lines generally sample at 8 KHz
 #define SYS_CLOCK 125000000.0f
 #define AUDIO_WRAP 250.0f
-#define AUDIO_RATE 11000.0f
 #define AUDIO_CLK_DIV (SYS_CLOCK / AUDIO_WRAP / 8 / AUDIO_RATE)
 
 void init_audio() {
@@ -49,7 +59,7 @@ void init_audio() {
 
     // set the handle function above
     irq_set_exclusive_handler(PWM_IRQ_WRAP, pwm_interrupt_handler);
-    irq_set_enabled(PWM_IRQ_WRAP, true);
+    // irq_set_enabled(PWM_IRQ_WRAP, true);
 
     // Setup PWM for audio output
     pwm_config config = pwm_get_default_config();
@@ -60,3 +70,17 @@ void init_audio() {
 
     pwm_set_gpio_level(AUDIO_PIN, 0);
 }
+
+void audio_stop() {
+    Serial.println("audio_stop");
+    irq_set_enabled(PWM_IRQ_WRAP, false);
+    pwm_set_gpio_level(AUDIO_PIN, 0);
+}
+
+void audio_start() {
+    Serial.println("audio_start");
+    audio_stop();
+    pwm_position = 0;
+    wav_buffer1_active = false;
+    irq_set_enabled(PWM_IRQ_WRAP, true);
+}

firmware/src/audio.h

@@ -1 +1,19 @@
+#pragma once
+
+#ifndef _audio_h
+#define _audio_h
+
+#define AUDIO_RATE 11000.0f
+#define BUFFER_LEN 8192
+#define BUFFER_LEN_MS (BUFFER_LEN / AUDIO_RATE) * 1000.0f
+
+extern uint8_t wav_buffer_0[BUFFER_LEN];
+extern uint8_t wav_buffer_1[BUFFER_LEN];
+extern bool wav_buffer1_active;
+extern volatile bool next_buffer_requested;
+
 void init_audio();
+void audio_stop();
+void audio_start();
+
+#endif

firmware/src/main.cpp

@@ -75,6 +75,8 @@ void setup() {
 
   setupSD();
 
+  sd_getAudio();
+
   return;
 
   memset(framebuffer, 0, sizeof(framebuffer));

firmware/src/sd.cpp

@@ -1,6 +1,8 @@
 #include <Arduino.h>
-#include <RP2040_SD.h>
 #include <SPI.h>
+#include <RP2040_SD.h>
+#include "sd.h"
+#include "audio.h"
 
 #define SD_DET_PIN 28
 
@@ -39,22 +41,23 @@ void printDirectory(File dir, int numTabs);
 void setupSD() {
   SPI.begin();
 
-  printSDConfig();
+  // printSDConfig();
 
   if (!SD.begin(PIN_SPI_SS)) {
     Serial.println("SD Initialization failed!");
     // Serial.print("Error code: ");
     // Serial.println(SD.card.errorCode(), HEX);
+    while (true) {}
     return;
   }
 
   Serial.println("SD Initialization done");
 
-  testSDCard();
+  // testSDCard();
   // printSDStats(SD.volume);
 
-  File root = SD.open("/");
-  printDirectory(root, 0);
+  // File root = SD.open("/");
+  // printDirectory(root, 0);
 }
 
 void printSDConfig() {
@@ -151,3 +154,54 @@ void printSDStats(RP2040_SdVolume volume) {
   Serial.print("Volume size (GB):  ");
   Serial.println((float)volumesize / 1024.0);
 }
+
+File file;
+
+void sd_getAudio() {
+  if (!SD.exists("/badapple/audio.bin")) {
+    Serial.println("Audio not found :(");
+    return;
+  }
+
+  if (file) {
+    file.close();
+  }
+
+  file = SD.open("/badapple/audio.bin", FILE_READ);
+  Serial.println("Audio file opened");
+
+  audio_stop();
+
+  // load two buffers' worth of audio
+  if (file.read(&wav_buffer_0, BUFFER_LEN) < BUFFER_LEN) {
+    Serial.println("Could not read first sample");
+    return;
+  }
+
+  if (file.read(&wav_buffer_1, BUFFER_LEN) < BUFFER_LEN) {
+    Serial.println("Could not read second sample");
+    return;
+  }
+
+  audio_start();
+
+  while (true) {
+    if (!next_buffer_requested) {
+      delay(50);
+      continue;
+    }
+    next_buffer_requested = false;
+
+    auto next_buffer = wav_buffer1_active ? &wav_buffer_0 : &wav_buffer_1;
+    auto bytesRead = file.read(next_buffer, BUFFER_LEN);
+
+    if (bytesRead < BUFFER_LEN) {
+      Serial.println("End of audio file");
+      file.seek(0);
+    } else {
+      Serial.print("Read ");
+      Serial.print(bytesRead);
+      Serial.println(" bytes from audio file");
+    }
+  }
+}

firmware/src/sd.h

@@ -1,4 +1,8 @@
+#pragma once
+
 void setupSDPins();
 void setupSD();
 
 bool isSDCardInserted();
+
+void sd_getAudio();