Example tidyups

Author: ideoforms

examples/ESP32Receive/ESP32Receive.ino

@@ -1,6 +1,7 @@
 /**-----------------------------------------------------------------------------
 
-    Example code to receive data using ESP32 and SPH0645 microphone
+    Example code using the Chirp SDK to receive data using ESP32 and
+    SPH0645 microphone
 
     @file ESP32Receive.ino
 
@@ -27,19 +28,20 @@
 #define I2SI_BCK          14     // I2S BCLK on GPIO14
 #define I2SI_LRCL         15     // I2S SELECT on GPIO15
 
-#define LED_PIN           2      // LED
-#define SWITCH_PIN        0      // Switch
+#define LED_PIN           2      // Pin number for on-board LED
+#define SWITCH_PIN        0      // Pin number for on-board switch
 
-#define BUFFER_SIZE       512
-#define MIC_CALIBRATION   13125
-#define SAMPLE_RATE       16000
+#define BUFFER_SIZE       512    // Audio buffer size
+#define SAMPLE_RATE       16000  // Audio sample rate
 
 /**
    Convert I2S input data.
    Data is 18 bit signed, MSBit first, two's complement.
-   The calibration value is determined using the Serial
-   Plotter to centre the audio about zero.
+   The MIC_CALIBRATION value is determined using the Serial
+   Plotter to centre the audio about zero. The below value
+   should be correct for most ESP32 boards.
 */
+#define MIC_CALIBRATION   13125
 #define CONVERT_INPUT(sample) (((int32_t)(sample) >> 14) + MIC_CALIBRATION)
 
 // Global variables ------------------------------------------------------------
@@ -72,7 +74,8 @@ loop()
   esp_err_t audioError;
   chirp_connect_error_code_t chirpError;
 
-  if (startTasks) {
+  if (startTasks)
+  {
     xTaskCreate(processInputTask, "processInputTask", 16384, NULL, 5, NULL);
     startTasks = false;
   }
@@ -85,7 +88,8 @@ initTask(void *parameter)
 {
   setupChirp();
 
-  uint32_t input_sample_rate = chirp_connect_set_input_sample_rate(chirp, SAMPLE_RATE);
+  chirp_connect_error_code_t chirpError = chirp_connect_set_input_sample_rate(chirp, SAMPLE_RATE);
+  chirpErrorHandler(chirpError);
   setupAudioInput(SAMPLE_RATE);
 
   Serial.printf("Heap size: %u\n", ESP.getFreeHeap());
@@ -103,11 +107,14 @@ processInputTask(void *parameter)
   float buffer[BUFFER_SIZE] = {0};
   int32_t ibuffer[BUFFER_SIZE] = {0};
 
-  while (currentState >= CHIRP_CONNECT_STATE_RUNNING) {
+  while (currentState >= CHIRP_CONNECT_STATE_RUNNING)
+  {
     audioError = i2s_read(I2S_NUM_0, ibuffer, BUFFER_SIZE * 4, &bytesLength, portMAX_DELAY);
-    if (bytesLength) {
-      for (int i = 0; i < bytesLength / 4; i++) {
-        buffer[i] = (float)CONVERT_INPUT(ibuffer[i]);
+    if (bytesLength)
+    {
+      for (int i = 0; i < bytesLength / 4; i++)
+      {
+        buffer[i] = (float) CONVERT_INPUT(ibuffer[i]);
       }
 
       chirpError = chirp_connect_process_input(chirp, buffer, bytesLength / 4);
@@ -136,12 +143,15 @@ onReceivingCallback(void *chirp, uint8_t *payload, size_t length, uint8_t channe
 void
 onReceivedCallback(void *chirp, uint8_t *payload, size_t length, uint8_t channel)
 {
-  if (payload) {
+  if (payload)
+  {
     char *data = chirp_connect_as_string((chirp_connect_t *)chirp, payload, length);
     Serial.printf("data = %s\n", data);
     digitalWrite(LED_PIN, LOW);
     chirp_connect_free(data);
-  } else {
+  }
+  else
+  {
     Serial.println("Decode failed.");
   }
 }
@@ -150,7 +160,8 @@ void
 setupChirp()
 {
   chirp = new_chirp_connect(CHIRP_APP_KEY, CHIRP_APP_SECRET);
-  if (chirp == NULL) {
+  if (chirp == NULL)
+  {
     Serial.println("Chirp initialisation failed.");
     return;
   }
@@ -197,7 +208,8 @@ setupAudioInput(int sample_rate)
   esp_err_t err;
   Serial.println("Initialising audio input driver..");
 
-  const i2s_config_t i2s_config = {
+  const i2s_config_t i2s_config =
+  {
     .mode = i2s_mode_t(I2S_MODE_MASTER | I2S_MODE_RX),
     .sample_rate = sample_rate,
     .bits_per_sample = I2S_BITS_PER_SAMPLE_32BIT,
@@ -209,27 +221,31 @@ setupAudioInput(int sample_rate)
     .use_apll = true
   };
 
-  const i2s_pin_config_t pin_config = {
+  const i2s_pin_config_t pin_config =
+  {
     .bck_io_num = I2SI_BCK,
     .ws_io_num = I2SI_LRCL,
     .data_out_num = I2S_PIN_NO_CHANGE,
     .data_in_num = I2SI_DATA
   };
 
   err = i2s_driver_install(I2S_NUM_0, &i2s_config, 0, NULL);
-  if (err != ESP_OK) {
+  if (err != ESP_OK)
+  {
     Serial.printf("Failed installing driver: %d\n", err);
     while (true);
   }
 
   err = i2s_set_pin(I2S_NUM_0, &pin_config);
-  if (err != ESP_OK) {
+  if (err != ESP_OK)
+  {
     Serial.printf("Failed setting pin: %d\n", err);
     while (true);
   }
 
   err = i2s_set_sample_rates(I2S_NUM_0, sample_rate);
-  if (err != ESP_OK) {
+  if (err != ESP_OK)
+  {
     Serial.printf("Failed to set sample rates: %d\n", err);
     while (true);
   }

examples/ESP32Send/ESP32Send.ino

@@ -1,6 +1,7 @@
 /**-----------------------------------------------------------------------------
 
-    Example code to send data using ESP32 and UDA1334 audio output
+    Example code using the Chirpd SDK to send data using ESP32 and UDA1334
+    audio output
 
     @file ESP32Send.ino
 
@@ -27,11 +28,11 @@
 #define I2SO_BCK          18     // I2S BCLK on GPIO18
 #define I2SO_WSEL         5      // I2S SELECT on GPIO5
 
-#define LED_PIN           2      // LED
-#define SWITCH_PIN        0      // Switch
+#define LED_PIN           2      // Pin number for on-board LED
+#define SWITCH_PIN        0      // Pin number for on-board switch
 
-#define BUFFER_SIZE       512
-#define SAMPLE_RATE       16000
+#define BUFFER_SIZE       512    // Audio buffer size
+#define SAMPLE_RATE       16000  // Audio sample rate
 
 // Global variables ------------------------------------------------------------
 static chirp_connect_t *chirp = NULL;
@@ -67,12 +68,14 @@ loop()
   esp_err_t audioError;
   chirp_connect_error_code_t chirpError;
 
-  if (startTasks) {
+  if (startTasks)
+  {
     xTaskCreate(processOutputTask, "processOutputTask", 16384, NULL, 3, NULL);
     startTasks = false;
   }
 
-  if (buttonPressed) {
+  if (buttonPressed)
+  {
     size_t payloadLength = 0;
     uint8_t *payload = chirp_connect_random_payload(chirp, &payloadLength);
     chirp_connect_send(chirp, payload, payloadLength);
@@ -113,12 +116,14 @@ processOutputTask(void *parameter)
   short buffer[BUFFER_SIZE] = {0};
   int32_t ibuffer[BUFFER_SIZE] = {0};
 
-  while (currentState >= CHIRP_CONNECT_STATE_RUNNING) {
+  while (currentState >= CHIRP_CONNECT_STATE_RUNNING)
+  {
     chirpError = chirp_connect_process_shorts_output(chirp, buffer, BUFFER_SIZE);
     chirpErrorHandler(chirpError);
 
-    for (int i = 0; i < BUFFER_SIZE; i++) {
-      ibuffer[i] = (int32_t)buffer[i];
+    for (int i = 0; i < BUFFER_SIZE; i++)
+    {
+      ibuffer[i] = (int32_t) buffer[i];
     }
     audioError = i2s_write(I2S_NUM_1, ibuffer, BUFFER_SIZE * 4, &bytesLength, portMAX_DELAY);
   }
@@ -154,7 +159,8 @@ void
 setupChirp()
 {
   chirp = new_chirp_connect(CHIRP_APP_KEY, CHIRP_APP_SECRET);
-  if (chirp == NULL) {
+  if (chirp == NULL)
+  {
     Serial.println("Chirp initialisation failed.");
     return;
   }
@@ -204,7 +210,8 @@ setupAudioOutput(int sample_rate)
   esp_err_t err;
   Serial.println("Initialising audio output driver..");
 
-  const i2s_config_t i2s_config = {
+  const 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,
@@ -216,27 +223,31 @@ setupAudioOutput(int sample_rate)
     .use_apll = true
   };
 
-  const i2s_pin_config_t pin_config = {
+  const i2s_pin_config_t pin_config =
+  {
     .bck_io_num = I2SO_BCK,
     .ws_io_num = I2SO_WSEL,
     .data_out_num = I2SO_DATA,
     .data_in_num = I2S_PIN_NO_CHANGE
   };
 
   err = i2s_driver_install(I2S_NUM_1, &i2s_config, 0, NULL);
-  if (err != ESP_OK) {
+  if (err != ESP_OK)
+  {
     Serial.printf("Failed installing driver: %d\n", err);
     while (true);
   }
 
   err = i2s_set_pin(I2S_NUM_1, &pin_config);
-  if (err != ESP_OK) {
+  if (err != ESP_OK)
+  {
     Serial.printf("Failed setting pin: %d\n", err);
     while (true);
   }
 
   err = i2s_set_sample_rates(I2S_NUM_1, sample_rate);
-  if (err != ESP_OK) {
+  if (err != ESP_OK)
+  {
     Serial.printf("Failed to set sample rates: %d\n", err);
     while (true);
   }

examples/MKRZeroSend/MKRZeroSend.ino

@@ -1,6 +1,7 @@
 /**-----------------------------------------------------------------------------
 
-    Example code using MKRZero and UDA1334 audio output
+    Example code using the Chirp SDK to transmit data over sound, using the
+    MKRZero and UDA1334 audio output.
 
     @file MKRZeroSend.ino
 
@@ -15,8 +16,8 @@
     These buffers are read directly by the I2S peripheral to output
     audio data.
 
-    *Note*: This board is send-only, so cannot be configured to receive
-    data due to the minimal memory available on the board
+    *Note*: This board is send-only as it does not have a floating-point unit
+    which is required to receive data.
 
     Circuit:
       - Arduino MKRZero
@@ -38,7 +39,7 @@
 #include "chirp_connect.h"
 #include "credentials.h"
 
-#define VOLUME            12000
+#define VOLUME            0.1
 
 #define NUM_BUFFERS       2
 #define BUFFER_SIZE       512
@@ -48,7 +49,8 @@
 
 int buffer[NUM_BUFFERS][BUFFER_SIZE];
 short tmpBuffer[BUFFER_SIZE / 2];
-uint8_t next, current;
+uint8_t nextBufferIndex, currentBufferIndex;
+uint16_t volumeInt;
 
 Adafruit_ZeroI2S i2s;
 Adafruit_ZeroDMA dma;
@@ -68,7 +70,8 @@ void setupChirp(void);
 
 void setup()
 {
-  current = 0;
+  currentBufferIndex = 0;
+  volumeInt = VOLUME * INT16_MAX;
 
   Serial.begin(115200);
   while(!Serial);  // Wait for Serial monitor before continuing
@@ -101,18 +104,19 @@ void setup()
 
 void loop()
 {
-  if (dma_complete) {
-    next = (current + 1) % NUM_BUFFERS;
+  if (dma_complete)
+  {
+    nextBufferIndex = (currentBufferIndex + 1) % NUM_BUFFERS;
 
     // Process data in to the next mono buffer
     chirp_connect_error_code_t err = chirp_connect_process_shorts_output(chirp, tmpBuffer, BUFFER_SIZE / 2);
     chirpErrorHandler(err);
 
     // Copy the data into a stereo buffer for audio output
     for (int i = 0; i < BUFFER_SIZE / 2; i++) {
-      int value = tmpBuffer[i] * VOLUME;
-      buffer[next][i * 2] = value;
-      buffer[next][i * 2 + 1] = value;
+      int value = tmpBuffer[i] * volumeInt;
+      buffer[nextBufferIndex][i * 2] = value;
+      buffer[nextBufferIndex][i * 2 + 1] = value;
     }
 
     dma_complete = false;
@@ -178,15 +182,19 @@ void setupChirp(void)
 
 void dmaCallback(Adafruit_ZeroDMA *dma)
 {
-  current++;
-  if (current >= NUM_BUFFERS) {
-    current -= NUM_BUFFERS;
+  currentBufferIndex++;
+  if (currentBufferIndex >= NUM_BUFFERS)
+  {
+    currentBufferIndex -= NUM_BUFFERS;
   }
-  dma->changeDescriptor(desc, buffer[current]);
+  dma->changeDescriptor(desc, buffer[currentBufferIndex]);
   ZeroDMAstatus stat = dma->startJob();
-  if (stat == DMA_STATUS_OK) {
+  if (stat == DMA_STATUS_OK)
+  {
     dma_complete = true;
-  } else {
+  }
+  else
+  {
     Serial.println("ERROR");
   }
 }
@@ -208,7 +216,7 @@ void setupDMA(void)
 
   Serial.println("Setting up transfer");
   desc = dma.addDescriptor(
-    buffer[current],
+    buffer[currentBufferIndex],
     (void *)(&I2S->DATA[0].reg),
     BUFFER_SIZE,
     DMA_BEAT_SIZE_WORD,

examples/MXChipSendReceive/MXChipSendReceive.ino

@@ -1,6 +1,6 @@
 /**------------------------------------------------------------------------------
  *
- *  Simple example of the Chirp C SDK on the Microsoft MXChip IoT DevKit.
+ *  Simple example using the Chirp SDK on the Microsoft MXChip IoT DevKit.
  *
  *  @file MXChipSendReceive.ino
  *