1 files changed, 142 insertions, 0 deletions
diff --git a/src/js/uBit.js b/src/js/uBit.js
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+/*
+ * This code is written with a lot of help from these resources:
+ * https://github.com/antefact/microBit.js/blob/master/src/microBit.js
+ * https://gist.github.com/kotobuki/7c67f8b9361e08930da1a5cfcfb0653f
+ * https://lancaster-university.github.io/microbit-docs/resources/bluetooth/bluetooth_profile.html
+ */
+const UART_SERVICE_UUID                      = "6e400001-b5a3-f393-e0a9-e50e24dcca9e";
+/* Used for reading UART data from micro bit */
+const UART_TX_CHARACTERISTIC_UUID            = "6e400002-b5a3-f393-e0a9-e50e24dcca9e";
+/* Used for writing UART data to micro bit */
+const UART_RX_CHARACTERISTIC_UUID            = "6e400003-b5a3-f393-e0a9-e50e24dcca9e";
+/* The event service characteristic (which extends the uBit message bus over bluetooth) */
+const EVENT_SERVICE_CHARACTERISTIC_UUID      = "e95d93af-251d-470a-a062-fa1922dfa9a8";
+/* This should be read once connected, as the ubit will advertise which events it wants to subscribe to */
+const UBIT_REQUIREMENT_CHARACTERISTIC_UUID   = "e95db84c-251d-470a-a062-fa1922dfa9a8";
+/* The characteristic where we should write the events we wish to be informed of from the microbit */
+const CLIENTREQUIREMENTS_CHARACTERISTIC_UUID = "e95d23c4-251d-470a-a062-fa1922dfa9a8"
+/* The characteristic used for reading EventService messages */
+const UBITEVENT_CHARACTERISTIC_UUID          = "e95d9775-251d-470a-a062-fa1922dfa9a8";
+/* The characteristic used for writing EventService messages */
+const CLIENTEVENT_CHARACTERISTIC_UUID        = "e95d5404-251d-470a-a062-fa1922dfa9a8";
+
+/* This table is retrieved from this site:
+ * https://github.com/lancaster-university/microbit-dal/blob/master/inc/bluetooth/MESEvents.h */
+export const MESEvents = {
+    MES_DPAD_CONTROLLER_ID: 1104,
+    MES_DPAD_BUTTON_A_DOWN: 1,
+    MES_DPAD_BUTTON_A_UP:   2,
+    MES_DPAD_BUTTON_B_DOWN: 3,
+    MES_DPAD_BUTTON_B_UP:   4,
+    MES_DPAD_BUTTON_C_DOWN: 5,
+    MES_DPAD_BUTTON_C_UP:   6,
+    MES_DPAD_BUTTON_D_DOWN: 7,
+    MES_DPAD_BUTTON_D_UP:   8,
+    MES_DPAD_BUTTON_1_DOWN: 9,
+    MES_DPAD_BUTTON_1_UP:   10,
+    MES_DPAD_BUTTON_2_DOWN: 11,
+    MES_DPAD_BUTTON_2_UP:   12,
+    MES_DPAD_BUTTON_3_DOWN: 13,
+    MES_DPAD_BUTTON_3_UP:   14,
+    MES_DPAD_BUTTON_4_DOWN: 15,
+    MES_DPAD_BUTTON_4_UP:   16
+}
+
+class BluetoothService {
+    SERVICE_UUID = null;
+}
+
+class EventService extends BluetoothService {
+    static SERVICE_UUID = EVENT_SERVICE_CHARACTERISTIC_UUID;
+    service;
+
+    constructor(service, ubitEvent) {
+        super();
+        this.service = service;
+        this.ubitEvent = ubitEvent;
+        console.log("EventService initialized.");
+    }
+
+    sendEvent(event_type, event_value) {
+        this.ubitEvent.writeValue(
+            new Uint16Array([event_type, event_value])
+        );
+    }
+
+    static async getService(gattServer) {
+        console.debug("Getting EventService");
+        let service = await gattServer.getPrimaryService(EventService.SERVICE_UUID);
+        console.debug("Getting UBitevent characteristic");
+        let ubitEventCharacteristic = await service.getCharacteristic(CLIENTEVENT_CHARACTERISTIC_UUID);
+        return new EventService(service, ubitEventCharacteristic);
+    }
+}
+
+export class uBitBLE {
+    eventService;
+    device;
+
+    constructor() {
+        this.onConnectCallback = function() {};
+        this.onDisconnectCallback = function() {};
+    }
+
+    onConnect(callbackFunction) {
+        this.onConnectCallback = callbackFunction;
+    }
+
+    onDisconnect(callbackFunction) {
+        this.onDisconnectCallback = callbackFunction;
+    }
+
+    isConnected() {
+        if (this.device) {
+            return this.device.gatt.connected;
+        } else {
+            return false;
+        }
+    }
+
+    disconnect() {
+        if (this.isConnected()) {
+            this.device.gatt.disconnect();
+        }
+    }
+
+    async searchDevice() {
+        this.device = await navigator.bluetooth.requestDevice({
+            filters: [{namePrefix: "BBC micro:bit"}],
+            optionalServices: [EVENT_SERVICE_CHARACTERISTIC_UUID]
+        });
+        this.device.addEventListener('gattserverdisconnected', this.onDisconnectCallback);
+        console.log("Connected to new device", this.device.name, this.device.id);
+
+        console.debug("Connection to GATT server...");
+        const server = await this.device.gatt.connect()
+
+        this.onConnectCallback();
+        console.debug("Getting services...");
+
+        const eventService = await EventService.getService(server);
+        this.eventService = eventService;
+    }
+
+}
+
+function getSupportedProperties(characteristic) {
+    let supportedProperties = [];
+    for (const p in characteristic.properties) {
+        if (characteristic.properties[p] === true) {
+            supportedProperties.push(p.toUpperCase());
+        }
+    }
+    return '[' + supportedProperties.join(', ') + ']';
+}
+
+function eventByteArrayToString(event) {
+    let receivedData = [];
+    for (var i = 0; i < event.target.value.byteLength; i++) {
+        receivedData[i] = event.target.value.getUint8(i);
+    }
+    return String.fromCharCode.apply(null, receivedData);
+}