MicroBitAccelerometerService.cpp

00001 /*
00002 The MIT License (MIT)
00003 
00004 Copyright (c) 2016 British Broadcasting Corporation.
00005 This software is provided by Lancaster University by arrangement with the BBC.
00006 
00007 Permission is hereby granted, free of charge, to any person obtaining a
00008 copy of this software and associated documentation files (the "Software"),
00009 to deal in the Software without restriction, including without limitation
00010 the rights to use, copy, modify, merge, publish, distribute, sublicense,
00011 and/or sell copies of the Software, and to permit persons to whom the
00012 Software is furnished to do so, subject to the following conditions:
00013 
00014 The above copyright notice and this permission notice shall be included in
00015 all copies or substantial portions of the Software.
00016 
00017 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
00018 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
00019 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
00020 THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
00021 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
00022 FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
00023 DEALINGS IN THE SOFTWARE.
00024 */
00025 
00026 /**
00027   * Class definition for the custom MicroBit Accelerometer Service.
00028   * Provides a BLE service to remotely read the state of the accelerometer, and configure its behaviour.
00029   */
00030 #include "MicroBitConfig.h"
00031 #include "ble/UUID.h"
00032 
00033 #include "MicroBitAccelerometerService.h"
00034 
00035 /**
00036   * Constructor.
00037   * Create a representation of the AccelerometerService
00038   * @param _ble The instance of a BLE device that we're running on.
00039   * @param _accelerometer An instance of MicroBitAccelerometer.
00040   */
00041 MicroBitAccelerometerService::MicroBitAccelerometerService(BLEDevice &_ble, MicroBitAccelerometer &_accelerometer) :
00042         ble(_ble), accelerometer(_accelerometer)
00043 {
00044     // Create the data structures that represent each of our characteristics in Soft Device.
00045     GattCharacteristic  accelerometerDataCharacteristic(MicroBitAccelerometerServiceDataUUID, (uint8_t *)accelerometerDataCharacteristicBuffer, 0,
00046     sizeof(accelerometerDataCharacteristicBuffer), GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_READ | GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_NOTIFY);
00047 
00048     GattCharacteristic  accelerometerPeriodCharacteristic(MicroBitAccelerometerServicePeriodUUID, (uint8_t *)&accelerometerPeriodCharacteristicBuffer, 0,
00049     sizeof(accelerometerPeriodCharacteristicBuffer),
00050     GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_READ | GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_WRITE);
00051 
00052     // Initialise our characteristic values.
00053     accelerometerDataCharacteristicBuffer[0] = 0;
00054     accelerometerDataCharacteristicBuffer[1] = 0;
00055     accelerometerDataCharacteristicBuffer[2] = 0;
00056     accelerometerPeriodCharacteristicBuffer = accelerometer.getPeriod();
00057 
00058     // Set default security requirements
00059     accelerometerDataCharacteristic.requireSecurity(SecurityManager::MICROBIT_BLE_SECURITY_LEVEL);
00060     accelerometerPeriodCharacteristic.requireSecurity(SecurityManager::MICROBIT_BLE_SECURITY_LEVEL);
00061 
00062     GattCharacteristic *characteristics[] = {&accelerometerDataCharacteristic, &accelerometerPeriodCharacteristic};
00063     GattService         service(MicroBitAccelerometerServiceUUID, characteristics, sizeof(characteristics) / sizeof(GattCharacteristic *));
00064 
00065     ble.addService(service);
00066 
00067     accelerometerDataCharacteristicHandle = accelerometerDataCharacteristic.getValueHandle();
00068     accelerometerPeriodCharacteristicHandle = accelerometerPeriodCharacteristic.getValueHandle();
00069 
00070     ble.gattServer().write(accelerometerDataCharacteristicHandle,(uint8_t *)accelerometerDataCharacteristicBuffer, sizeof(accelerometerDataCharacteristicBuffer));
00071     ble.gattServer().write(accelerometerPeriodCharacteristicHandle, (const uint8_t *)&accelerometerPeriodCharacteristicBuffer, sizeof(accelerometerPeriodCharacteristicBuffer));
00072 
00073     ble.onDataWritten(this, &MicroBitAccelerometerService::onDataWritten);
00074 
00075     if (EventModel::defaultEventBus)
00076         EventModel::defaultEventBus->listen(MICROBIT_ID_ACCELEROMETER, MICROBIT_ACCELEROMETER_EVT_DATA_UPDATE, this, &MicroBitAccelerometerService::accelerometerUpdate,  MESSAGE_BUS_LISTENER_IMMEDIATE);
00077 }
00078 
00079 /**
00080   * Callback. Invoked when any of our attributes are written via BLE.
00081   */
00082 void MicroBitAccelerometerService::onDataWritten(const GattWriteCallbackParams *params)
00083 {
00084     if (params->handle == accelerometerPeriodCharacteristicHandle && params->len >= sizeof(accelerometerPeriodCharacteristicBuffer))
00085     {
00086         accelerometerPeriodCharacteristicBuffer = *((uint16_t *)params->data);
00087         accelerometer.setPeriod(accelerometerPeriodCharacteristicBuffer);
00088 
00089         // The accelerometer will choose the nearest period to that requested that it can support
00090         // Read back the ACTUAL period it is using, and report this back.
00091         accelerometerPeriodCharacteristicBuffer = accelerometer.getPeriod();
00092         ble.gattServer().write(accelerometerPeriodCharacteristicHandle, (const uint8_t *)&accelerometerPeriodCharacteristicBuffer, sizeof(accelerometerPeriodCharacteristicBuffer));
00093     }
00094 }
00095 
00096 /**
00097   * Accelerometer update callback
00098   */
00099 void MicroBitAccelerometerService::accelerometerUpdate(MicroBitEvent)
00100 {
00101     if (ble.getGapState().connected)
00102     {
00103         accelerometerDataCharacteristicBuffer[0] = accelerometer.getX();
00104         accelerometerDataCharacteristicBuffer[1] = accelerometer.getY();
00105         accelerometerDataCharacteristicBuffer[2] = accelerometer.getZ();
00106 
00107         ble.gattServer().notify(accelerometerDataCharacteristicHandle,(uint8_t *)accelerometerDataCharacteristicBuffer, sizeof(accelerometerDataCharacteristicBuffer));
00108     }
00109 }
00110 
00111 const uint8_t  MicroBitAccelerometerServiceUUID[] = {
00112     0xe9,0x5d,0x07,0x53,0x25,0x1d,0x47,0x0a,0xa0,0x62,0xfa,0x19,0x22,0xdf,0xa9,0xa8
00113 };
00114 
00115 const uint8_t  MicroBitAccelerometerServiceDataUUID[] = {
00116     0xe9,0x5d,0xca,0x4b,0x25,0x1d,0x47,0x0a,0xa0,0x62,0xfa,0x19,0x22,0xdf,0xa9,0xa8
00117 };
00118 
00119 const uint8_t  MicroBitAccelerometerServicePeriodUUID[] = {
00120     0xe9,0x5d,0xfb,0x24,0x25,0x1d,0x47,0x0a,0xa0,0x62,0xfa,0x19,0x22,0xdf,0xa9,0xa8
00121 };