Diff: source/bluetooth/MicroBitMagnetometerService.cpp

Revision:

1:8aa5cdb4ab67

Child:

21:cab56b701601

diff -r fb15f7887843 -r 8aa5cdb4ab67 source/bluetooth/MicroBitMagnetometerService.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/source/bluetooth/MicroBitMagnetometerService.cpp	Thu Apr 07 01:33:22 2016 +0100
@@ -0,0 +1,156 @@
+/*
+The MIT License (MIT)
+
+Copyright (c) 2016 British Broadcasting Corporation.
+This software is provided by Lancaster University by arrangement with the BBC.
+
+Permission is hereby granted, free of charge, to any person obtaining a
+copy of this software and associated documentation files (the "Software"),
+to deal in the Software without restriction, including without limitation
+the rights to use, copy, modify, merge, publish, distribute, sublicense,
+and/or sell copies of the Software, and to permit persons to whom the
+Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+DEALINGS IN THE SOFTWARE.
+*/
+
+/**
+  * Class definition for the MicroBit BLE Magnetometer Service.
+  * Provides access to live magnetometer data via BLE, and provides basic configuration options.
+  */
+#include "MicroBitConfig.h"
+#include "ble/UUID.h"
+
+#include "MicroBitMagnetometerService.h"
+
+/**
+  * Constructor.
+  * Create a representation of the MagnetometerService.
+  * @param _ble The instance of a BLE device that we're running on.
+  * @param _compass An instance of MicroBitCompass to use as our Magnetometer source.
+  */
+MicroBitMagnetometerService::MicroBitMagnetometerService(BLEDevice &_ble, MicroBitCompass &_compass) :
+        ble(_ble), compass(_compass)
+{
+    // Create the data structures that represent each of our characteristics in Soft Device.
+    GattCharacteristic  magnetometerDataCharacteristic(MicroBitMagnetometerServiceDataUUID, (uint8_t *)magnetometerDataCharacteristicBuffer, 0,
+    sizeof(magnetometerDataCharacteristicBuffer), GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_READ | GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_NOTIFY);
+
+    GattCharacteristic  magnetometerBearingCharacteristic(MicroBitMagnetometerServiceBearingUUID, (uint8_t *)&magnetometerBearingCharacteristicBuffer, 0,
+    sizeof(magnetometerBearingCharacteristicBuffer), GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_READ | GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_NOTIFY);
+
+    GattCharacteristic  magnetometerPeriodCharacteristic(MicroBitMagnetometerServicePeriodUUID, (uint8_t *)&magnetometerPeriodCharacteristicBuffer, 0,
+    sizeof(magnetometerPeriodCharacteristicBuffer),
+    GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_READ | GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_WRITE);
+
+    // Initialise our characteristic values.
+    magnetometerDataCharacteristicBuffer[0] = 0;
+    magnetometerDataCharacteristicBuffer[1] = 0;
+    magnetometerDataCharacteristicBuffer[2] = 0;
+    magnetometerBearingCharacteristicBuffer = 0;
+    magnetometerPeriodCharacteristicBuffer = compass.getPeriod();
+
+    // Set default security requirements
+    magnetometerDataCharacteristic.requireSecurity(SecurityManager::MICROBIT_BLE_SECURITY_LEVEL);
+    magnetometerBearingCharacteristic.requireSecurity(SecurityManager::MICROBIT_BLE_SECURITY_LEVEL);
+    magnetometerPeriodCharacteristic.requireSecurity(SecurityManager::MICROBIT_BLE_SECURITY_LEVEL);
+
+    GattCharacteristic *characteristics[] = {&magnetometerDataCharacteristic, &magnetometerBearingCharacteristic, &magnetometerPeriodCharacteristic};
+    GattService         service(MicroBitMagnetometerServiceUUID, characteristics, sizeof(characteristics) / sizeof(GattCharacteristic *));
+
+    ble.addService(service);
+
+    magnetometerDataCharacteristicHandle = magnetometerDataCharacteristic.getValueHandle();
+    magnetometerBearingCharacteristicHandle = magnetometerBearingCharacteristic.getValueHandle();
+    magnetometerPeriodCharacteristicHandle = magnetometerPeriodCharacteristic.getValueHandle();
+
+    ble.gattServer().notify(magnetometerDataCharacteristicHandle,(uint8_t *)magnetometerDataCharacteristicBuffer, sizeof(magnetometerDataCharacteristicBuffer));
+    ble.gattServer().notify(magnetometerBearingCharacteristicHandle,(uint8_t *)&magnetometerBearingCharacteristicBuffer, sizeof(magnetometerDataCharacteristicBuffer));
+    ble.gattServer().write(magnetometerPeriodCharacteristicHandle, (const uint8_t *)&magnetometerPeriodCharacteristicBuffer, sizeof(magnetometerPeriodCharacteristicBuffer));
+
+    ble.onDataWritten(this, &MicroBitMagnetometerService::onDataWritten);
+    if (EventModel::defaultEventBus)
+    {
+        EventModel::defaultEventBus->listen(MICROBIT_ID_COMPASS, MICROBIT_COMPASS_EVT_DATA_UPDATE, this, &MicroBitMagnetometerService::magnetometerUpdate, MESSAGE_BUS_LISTENER_IMMEDIATE);
+        EventModel::defaultEventBus->listen(MICROBIT_ID_COMPASS, MICROBIT_COMPASS_EVT_CONFIG_NEEDED, this, &MicroBitMagnetometerService::samplePeriodUpdateNeeded);
+    }
+}
+
+/**
+  * Callback. Invoked when any of our attributes are written via BLE.
+  */
+void MicroBitMagnetometerService::onDataWritten(const GattWriteCallbackParams *params)
+{
+    if (params->handle == magnetometerPeriodCharacteristicHandle && params->len >= sizeof(magnetometerPeriodCharacteristicBuffer))
+    {
+        magnetometerPeriodCharacteristicBuffer = *((uint16_t *)params->data);
+        MicroBitEvent evt(MICROBIT_ID_COMPASS, MICROBIT_COMPASS_EVT_CONFIG_NEEDED);
+    }
+}
+
+/**
+  * Magnetometer update callback
+  */
+void MicroBitMagnetometerService::magnetometerUpdate(MicroBitEvent)
+{
+    if (ble.getGapState().connected)
+    {
+        magnetometerDataCharacteristicBuffer[0] = compass.getX();
+        magnetometerDataCharacteristicBuffer[1] = compass.getY();
+        magnetometerDataCharacteristicBuffer[2] = compass.getZ();
+        magnetometerPeriodCharacteristicBuffer = compass.getPeriod();
+
+        ble.gattServer().write(magnetometerPeriodCharacteristicHandle, (const uint8_t *)&magnetometerPeriodCharacteristicBuffer, sizeof(magnetometerPeriodCharacteristicBuffer));
+        ble.gattServer().notify(magnetometerDataCharacteristicHandle,(uint8_t *)magnetometerDataCharacteristicBuffer, sizeof(magnetometerDataCharacteristicBuffer));
+
+        if (compass.isCalibrated())
+        {
+            magnetometerBearingCharacteristicBuffer = (uint16_t) compass.heading();
+            ble.gattServer().notify(magnetometerBearingCharacteristicHandle,(uint8_t *)&magnetometerBearingCharacteristicBuffer, sizeof(magnetometerBearingCharacteristicBuffer));
+        }
+    }
+}
+
+/**
+ * Sample Period Change Needed callback.
+ * Reconfiguring the magnetometer can to a REALLY long time (sometimes even seconds to complete)
+ * So we do this in the background when necessary, through this event handler.
+ */
+void MicroBitMagnetometerService::samplePeriodUpdateNeeded(MicroBitEvent)
+{
+    // Reconfigure the compass. This might take a while...
+    compass.setPeriod(magnetometerPeriodCharacteristicBuffer);
+
+    // The compass will choose the nearest sample period to that we've specified.
+    // Read the ACTUAL sample period back.
+    magnetometerPeriodCharacteristicBuffer = compass.getPeriod();
+
+    // Ensure this is reflected in our BLE connection.
+    ble.gattServer().write(magnetometerPeriodCharacteristicHandle, (const uint8_t *)&magnetometerPeriodCharacteristicBuffer, sizeof(magnetometerPeriodCharacteristicBuffer));
+
+}
+
+const uint8_t  MicroBitMagnetometerServiceUUID[] = {
+    0xe9,0x5d,0xf2,0xd8,0x25,0x1d,0x47,0x0a,0xa0,0x62,0xfa,0x19,0x22,0xdf,0xa9,0xa8
+};
+
+const uint8_t  MicroBitMagnetometerServiceDataUUID[] = {
+    0xe9,0x5d,0xfb,0x11,0x25,0x1d,0x47,0x0a,0xa0,0x62,0xfa,0x19,0x22,0xdf,0xa9,0xa8
+};
+
+const uint8_t  MicroBitMagnetometerServicePeriodUUID[] = {
+    0xe9,0x5d,0x38,0x6c,0x25,0x1d,0x47,0x0a,0xa0,0x62,0xfa,0x19,0x22,0xdf,0xa9,0xa8
+};
+
+const uint8_t  MicroBitMagnetometerServiceBearingUUID[] = {
+    0xe9,0x5d,0x97,0x15,0x25,0x1d,0x47,0x0a,0xa0,0x62,0xfa,0x19,0x22,0xdf,0xa9,0xa8
+};