[WIP] Add xiao-nrf52840

devices/xiao-nrf52840/main.ino

@@ -0,0 +1,100 @@
+#include <ArduinoBLE.h>
+#include <mic.h>
+
+#define MIC_SERVICE_UUID "4fafc201-1fb5-459e-8fcc-c5c9c331914b"
+#define MIC_CHAR_UUID "beb5483e-36e1-4688-b7f5-ea07361b26a8"
+
+BLEService micService(MIC_SERVICE_UUID);
+BLECharacteristic micDataChar(MIC_CHAR_UUID, BLERead | BLENotify, 179);
+
+mic_config_t mic_config{
+    .channel_cnt = 1,
+    .sampling_rate = 16000,
+    .buf_size = 1600,
+    .debug_pin = LED_BUILTIN // Toggles each DAC ISR (if DEBUG is set to 1)
+};
+
+NRF52840_ADC_Class Mic(&mic_config);
+#define SAMPLES 179
+
+int16_t recording_buf[SAMPLES];
+volatile static bool record_ready = false;
+
+void setup()
+{
+    Serial.begin(115200);
+    while (!Serial)
+    {
+        delay(10);
+    }
+
+    // Set callback to the mic
+    Mic.set_callback(audio_rec_callback);
+
+    if (!Mic.begin())
+    {
+        Serial.println("Mic initialization failed");
+        while (1)
+            ;
+    }
+
+    if (!BLE.begin())
+    {
+        Serial.println("starting BLE failed");
+        while (1)
+            ;
+    }
+
+    BLE.setLocalName("ADeus");
+    BLE.setAdvertisedService(micService);
+    micService.addCharacteristic(micDataChar);
+    BLE.addService(micService);
+    BLE.advertise();
+
+    Serial.println("Bluetooth device active, waiting for connections...");
+}
+
+void loop()
+{
+    BLEDevice central = BLE.central();
+    // central
+
+    if (central)
+    {
+        Serial.print("Connected to central: ");
+        Serial.println(central.address());
+        digitalWrite(LED_BUILTIN, HIGH);
+
+        while (central.connected())
+        {
+            if (record_ready)
+            {
+                Serial.println("finished sampling");
+                micDataChar.writeValue((uint8_t *)recording_buf, 179);
+                record_ready = false;
+            }
+        }
+
+        digitalWrite(LED_BUILTIN, LOW);
+        Serial.print("Disconnected from central: ");
+        Serial.println(central.address());
+    }
+}
+
+static void audio_rec_callback(uint16_t *buf, uint32_t buf_len)
+{
+    static uint32_t idx = 0;
+
+    // Copy samples from DMA buffer to inference buffer
+    for (uint32_t i = 0; i < buf_len; i++)
+    {
+        recording_buf[idx++] = buf[i];
+
+        if (idx >= SAMPLES)
+        {
+            idx = 0;
+            record_ready = true;
+            break;
+        }
+    }
+}