HeartRateService.h

00001 /* mbed Microcontroller Library
00002  * Copyright (c) 2006-2013 ARM Limited
00003  *
00004  * Licensed under the Apache License, Version 2.0 (the "License");
00005  * you may not use this file except in compliance with the License.
00006  * You may obtain a copy of the License at
00007  *
00008  *     http://www.apache.org/licenses/LICENSE-2.0
00009  *
00010  * Unless required by applicable law or agreed to in writing, software
00011  * distributed under the License is distributed on an "AS IS" BASIS,
00012  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00013  * See the License for the specific language governing permissions and
00014  * limitations under the License.
00015  */
00016 
00017 #ifndef __BLE_HEART_RATE_SERVICE_H__
00018 #define __BLE_HEART_RATE_SERVICE_H__
00019 
00020 #include "ble/BLE.h"
00021 
00022 /**
00023 * @class HeartRateService
00024 * @brief BLE Service for HeartRate. This BLE Service contains the location of the sensor and the heart rate in beats per minute.
00025 * Service:  https://developer.bluetooth.org/gatt/services/Pages/ServiceViewer.aspx?u=org.bluetooth.service.heart_rate.xml
00026 * HRM Char: https://developer.bluetooth.org/gatt/characteristics/Pages/CharacteristicViewer.aspx?u=org.bluetooth.characteristic.heart_rate_measurement.xml
00027 * Location: https://developer.bluetooth.org/gatt/characteristics/Pages/CharacteristicViewer.aspx?u=org.bluetooth.characteristic.body_sensor_location.xml
00028 */
00029 class HeartRateService {
00030 public:
00031     /**
00032     * @enum SensorLocation
00033     * @brief Location of the heart rate sensor on body.
00034     */
00035     enum {
00036         LOCATION_OTHER  = 0, /*!< Other location. */
00037         LOCATION_CHEST ,     /*!< Chest. */
00038         LOCATION_WRIST ,     /*!< Wrist. */
00039         LOCATION_FINGER ,    /*!< Finger. */
00040         LOCATION_HAND ,      /*!< Hand. */
00041         LOCATION_EAR_LOBE ,  /*!< Earlobe. */
00042         LOCATION_FOOT ,      /*!< Foot. */
00043     };
00044 
00045 public:
00046     /**
00047      * @brief Constructor with 8-bit HRM Counter value.
00048      *
00049      * @param[ref] _ble
00050      *               Reference to the underlying BLE.
00051      * @param[in] hrmCounter (8-bit)
00052      *               Initial value for the HRM counter.
00053      * @param[in] location
00054      *               Sensor's location.
00055      */
00056     HeartRateService(BLE &_ble, uint8_t hrmCounter, uint8_t location) :
00057         ble(_ble),
00058         valueBytes(hrmCounter),
00059         hrmRate(GattCharacteristic::UUID_HEART_RATE_MEASUREMENT_CHAR, valueBytes.getPointer(),
00060                 valueBytes.getNumValueBytes(), HeartRateValueBytes::MAX_VALUE_BYTES,
00061                 GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_READ | GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_NOTIFY),
00062         hrmLocation(GattCharacteristic::UUID_BODY_SENSOR_LOCATION_CHAR, &location),
00063         controlPoint(GattCharacteristic::UUID_HEART_RATE_CONTROL_POINT_CHAR, &controlPointValue) {
00064         setupService();
00065     }
00066 
00067     /**
00068      * @brief Constructor with a 16-bit HRM Counter value.
00069      *
00070      * @param[in] _ble
00071      *               Reference to the underlying BLE.
00072      * @param[in] hrmCounter (8-bit)
00073      *               Initial value for the HRM counter.
00074      * @param[in] location
00075      *               Sensor's location.
00076      */
00077     HeartRateService(BLE &_ble, uint16_t hrmCounter, uint8_t location) :
00078         ble(_ble),
00079         valueBytes(hrmCounter),
00080         hrmRate(GattCharacteristic::UUID_HEART_RATE_MEASUREMENT_CHAR, valueBytes.getPointer(),
00081                 valueBytes.getNumValueBytes(), HeartRateValueBytes::MAX_VALUE_BYTES,
00082                 GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_NOTIFY),
00083         hrmLocation(GattCharacteristic::UUID_BODY_SENSOR_LOCATION_CHAR, &location),
00084         controlPoint(GattCharacteristic::UUID_HEART_RATE_CONTROL_POINT_CHAR, &controlPointValue) {
00085         setupService();
00086     }
00087 
00088     /**
00089      * @brief Set a new 8-bit value for the heart rate.
00090      *
00091      * @param[in] hrmCounter
00092      *                  Heart rate in BPM.
00093      */
00094     void updateHeartRate(uint8_t hrmCounter) {
00095         valueBytes.updateHeartRate(hrmCounter);
00096         ble.gattServer().write(hrmRate.getValueHandle(), valueBytes.getPointer(), valueBytes.getNumValueBytes());
00097     }
00098 
00099     /**
00100      * Set a new 16-bit value for the heart rate.
00101      *
00102      * @param[in] hrmCounter
00103      *                  Heart rate in BPM.
00104      */
00105     void updateHeartRate(uint16_t hrmCounter) {
00106         valueBytes.updateHeartRate(hrmCounter);
00107         ble.gattServer().write(hrmRate.getValueHandle(), valueBytes.getPointer(), valueBytes.getNumValueBytes());
00108     }
00109 
00110     /**
00111      * This callback allows the heart rate service to receive updates to the
00112      * controlPoint characteristic.
00113      *
00114      * @param[in] params
00115      *     Information about the characterisitc being updated.
00116      */
00117     virtual void onDataWritten(const GattWriteCallbackParams *params) {
00118         if (params->handle == controlPoint.getValueAttribute().getHandle()) {
00119             /* Do something here if the new value is 1; else you can override this method by
00120              * extending this class.
00121              * @NOTE: If you are extending this class, be sure to also call
00122              * ble.onDataWritten(this, &ExtendedHRService::onDataWritten); in
00123              * your constructor.
00124              */
00125         }
00126     }
00127 
00128 protected:
00129     void setupService(void) {
00130         GattCharacteristic *charTable[] = {&hrmRate, &hrmLocation, &controlPoint};
00131         GattService         hrmService(GattService::UUID_HEART_RATE_SERVICE, charTable, sizeof(charTable) / sizeof(GattCharacteristic *));
00132 
00133         ble.addService(hrmService);
00134         ble.onDataWritten(this, &HeartRateService::onDataWritten);
00135     }
00136 
00137 protected:
00138     /* Private internal representation for the bytes used to work with the value of the heart rate characteristic. */
00139     struct HeartRateValueBytes {
00140         static const unsigned MAX_VALUE_BYTES  = 3; /* Flags, and up to two bytes for heart rate. */
00141         static const unsigned FLAGS_BYTE_INDEX = 0;
00142 
00143         static const unsigned VALUE_FORMAT_BITNUM = 0;
00144         static const uint8_t  VALUE_FORMAT_FLAG   = (1 << VALUE_FORMAT_BITNUM);
00145 
00146         HeartRateValueBytes(uint8_t hrmCounter) : valueBytes() {
00147             updateHeartRate(hrmCounter);
00148         }
00149 
00150         HeartRateValueBytes(uint16_t hrmCounter) : valueBytes() {
00151             updateHeartRate(hrmCounter);
00152         }
00153 
00154         void updateHeartRate(uint8_t hrmCounter) {
00155             valueBytes[FLAGS_BYTE_INDEX]    &= ~VALUE_FORMAT_FLAG;
00156             valueBytes[FLAGS_BYTE_INDEX + 1] = hrmCounter;
00157         }
00158 
00159         void updateHeartRate(uint16_t hrmCounter) {
00160             valueBytes[FLAGS_BYTE_INDEX]    |= VALUE_FORMAT_FLAG;
00161             valueBytes[FLAGS_BYTE_INDEX + 1] = (uint8_t)(hrmCounter & 0xFF);
00162             valueBytes[FLAGS_BYTE_INDEX + 2] = (uint8_t)(hrmCounter >> 8);
00163         }
00164 
00165         uint8_t       *getPointer(void) {
00166             return valueBytes;
00167         }
00168 
00169         const uint8_t *getPointer(void) const {
00170             return valueBytes;
00171         }
00172 
00173         unsigned       getNumValueBytes(void) const {
00174             return 1 + ((valueBytes[FLAGS_BYTE_INDEX] & VALUE_FORMAT_FLAG) ? sizeof(uint16_t) : sizeof(uint8_t));
00175         }
00176 
00177     private:
00178         /* First byte: 8-bit values, no extra info. Second byte: uint8_t HRM value */
00179         /* See https://developer.bluetooth.org/gatt/characteristics/Pages/CharacteristicViewer.aspx?u=org.bluetooth.characteristic.heart_rate_measurement.xml */
00180         uint8_t valueBytes[MAX_VALUE_BYTES];
00181     };
00182 
00183 protected:
00184     BLE                 &ble;
00185 
00186     HeartRateValueBytes  valueBytes;
00187     uint8_t              controlPointValue;
00188 
00189     GattCharacteristic                   hrmRate;
00190     ReadOnlyGattCharacteristic<uint8_t>   hrmLocation;
00191     WriteOnlyGattCharacteristic<uint8_t>  controlPoint;
00192 };
00193 
00194 #endif /* #ifndef __BLE_HEART_RATE_SERVICE_H__*/