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Diff: services/HealthThermometerService.h
- Revision:
- 0:289fd2dae405
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/services/HealthThermometerService.h Fri Dec 19 18:54:46 2014 +0000 @@ -0,0 +1,131 @@ +/* mbed Microcontroller Library + * Copyright (c) 2006-2013 ARM Limited + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +#ifndef __BLE_HEALTH_THERMOMETER_SERVICE_H__ +#define __BLE_HEALTH_THERMOMETER_SERVICE_H__ + +#include "BLEDevice.h" + +/* Health Thermometer Service */ +/* Service: https://developer.bluetooth.org/gatt/profiles/Pages/ProfileViewer.aspx?u=org.bluetooth.profile.health_thermometer.xml */ +/* Temperature Measurement: https://developer.bluetooth.org/gatt/characteristics/Pages/CharacteristicViewer.aspx?u=org.bluetooth.characteristic.temperature_measurement.xml */ +/* Temperature Type: https://developer.bluetooth.org/gatt/characteristics/Pages/CharacteristicViewer.aspx?u=org.bluetooth.characteristic.temperature_type.xml */ +class HealthThermometerService { +public: + enum { + LOCATION_ARMPIT = 1, + LOCATION_BODY, + LOCATION_EAR, + LOCATION_FINGER, + LOCATION_GI_TRACT, + LOCATION_MOUTH, + LOCATION_RECTUM, + LOCATION_TOE, + LOCATION_EAR_DRUM, + }; + +public: + + /** + * @param[in] _ble reference to the BLE device + * @param[in] initialTemp initial value in celsius + * @param[in] _location + */ + HealthThermometerService(BLEDevice &_ble, float initialTemp, uint8_t _location) : + ble(_ble), + valueBytes(initialTemp), + tempMeasurement(GattCharacteristic::UUID_TEMPERATURE_MEASUREMENT_CHAR, valueBytes.getPointer(), + sizeof(TemperatureValueBytes), sizeof(TemperatureValueBytes), + GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_READ | GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_NOTIFY), + tempLocation(GattCharacteristic::UUID_TEMPERATURE_TYPE_CHAR, (uint8_t *)&_location, sizeof(_location), sizeof(_location), + GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_READ) { + + GattCharacteristic *hrmChars[] = {&tempMeasurement, &tempLocation, }; + GattService hrmService(GattService::UUID_HEALTH_THERMOMETER_SERVICE, hrmChars, sizeof(hrmChars) / sizeof(GattCharacteristic *)); + + ble.addService(hrmService); + } + + void updateTemperature(float temperature) { + if (ble.getGapState().connected) { + valueBytes.updateTemperature(temperature); + ble.updateCharacteristicValue(tempMeasurement.getValueAttribute().getHandle(), valueBytes.getPointer(), sizeof(TemperatureValueBytes)); + } + } + +private: + /* Private internal representation for the bytes used to work with the vaulue of the heart-rate characteristic. */ + struct TemperatureValueBytes { + static const unsigned OFFSET_OF_FLAGS = 0; + static const unsigned OFFSET_OF_VALUE = OFFSET_OF_FLAGS + sizeof(uint8_t); + static const unsigned SIZEOF_VALUE_BYTES = sizeof(uint8_t) + sizeof(float); + + static const unsigned TEMPERATURE_UNITS_FLAG_POS = 0; + static const unsigned TIMESTAMP_FLAG_POS = 1; + static const unsigned TEMPERATURE_TYPE_FLAG_POS = 2; + + static const uint8_t TEMPERATURE_UNITS_CELSIUS = 0; + static const uint8_t TEMPERATURE_UNITS_FAHRENHEIT = 1; + + TemperatureValueBytes(float initialTemperature) : bytes() { + /* assumption: temperature values are expressed in Celsius */ + bytes[OFFSET_OF_FLAGS] = (TEMPERATURE_UNITS_CELSIUS << TEMPERATURE_UNITS_FLAG_POS) | + (false << TIMESTAMP_FLAG_POS) | + (false << TEMPERATURE_TYPE_FLAG_POS); + updateTemperature(initialTemperature); + } + + void updateTemperature(float temp) { + uint32_t temp_ieee11073 = quick_ieee11073_from_float(temp); + memcpy(&bytes[OFFSET_OF_VALUE], &temp_ieee11073, sizeof(float)); + } + + uint8_t *getPointer(void) { + return bytes; + } + + const uint8_t *getPointer(void) const { + return bytes; + } + + private: + /** + * @brief A very quick conversion between a float temperature and 11073-20601 FLOAT-Type. + * @param temperature The temperature as a float. + * @return The temperature in 11073-20601 FLOAT-Type format. + */ + uint32_t quick_ieee11073_from_float(float temperature) { + uint8_t exponent = 0xFE; //exponent is -2 + uint32_t mantissa = (uint32_t)(temperature * 100); + + return (((uint32_t)exponent) << 24) | mantissa; + } + + + private: + /* First byte = 8-bit flags, Second field is a float holding the temperature value. */ + /* See --> https://developer.bluetooth.org/gatt/characteristics/Pages/CharacteristicViewer.aspx?u=org.bluetooth.characteristic.temperature_measurement.xml */ + uint8_t bytes[SIZEOF_VALUE_BYTES]; + }; + +private: + BLEDevice &ble; + TemperatureValueBytes valueBytes; + GattCharacteristic tempMeasurement; + GattCharacteristic tempLocation; +}; + +#endif /* #ifndef __BLE_HEALTH_THERMOMETER_SERVICE_H__*/