我正在使用示例 CustomGATTSvc 代码来熟悉 Movesense pod 上的 GATT 接口，但在尝试向代码中添加更多服务时遇到了问题。我的项目最终需要具备以下能力：
- 获取和设置 pod 上的 RTC
- 使用 Datalogger 和 Logbook 存储和检索加速度计数据。
所有这些都必须使用 GATT 接口来实现，因为我们希望在 Cordova 中开发移动应用程序，据我所知，它不支持 Movesense 库。
作为第一步，我尝试向示例代码中已经存在的 Health Thermometer 服务添加第二个服务。我希望实现当前时间服务（与当前时间服务相关的所有内容都包含在 #define CURRENT_TIME_SVC 中） -
#define THERMOMETER_SERV_UUID 0x1809 // Health Thermometer
#define CURRENT_TIME_SERV_UUID 0x1805 // Current Time Service
const uint16_t measCharUUID16 = 0x2A1C;
const uint16_t intervalCharUUID16 = 0x2A21;
const uint16_t healthThermometerSvcUUID16 = THERMOMETER_SERV_UUID; // Health Temperature probe
#ifdef CURRENT_TIME_SVC
const uint16_t timeCharUUID16 = 0x2A2C; //Random UUID for Current Time
const uint16_t timeSvcUUID16 = CURRENT_TIME_SERV_UUID; //Current Time
#endif
在 configGattSvc() 函数中，我将服务和特征配置如下：
WB_RES::GattSvc customGattThermometerSvc;
WB_RES::GattChar characteristics[2];
WB_RES::GattChar &measChar = characteristics[0];
WB_RES::GattChar &intervalChar = characteristics[1];
//const uint16_t healthThermometerSvcUUID16 = 0x1809;
#ifdef CURRENT_TIME_SVC
WB_RES::GattSvc customGattTimeSvc;
WB_RES::GattChar characteristicsTime[1];
WB_RES::GattChar &timeChar = characteristicsTime[0];
//const uint16_t timeSvcUUID16 = 0x1805;
#endif
// Define the CMD characteristics
WB_RES::GattProperty measCharProp = WB_RES::GattProperty::INDICATE;
WB_RES::GattProperty intervalCharProps[2] = {WB_RES::GattProperty::READ, WB_RES::GattProperty::WRITE};
WB_RES::GattProperty timeCharProps[3] = {WB_RES::GattProperty::READ, WB_RES::GattProperty::WRITE, WB_RES::GattProperty::NOTIFY};
measChar.props = whiteboard::MakeArray<WB_RES::GattProperty>( &measCharProp, 1);
measChar.uuid = whiteboard::MakeArray<uint8_t>( reinterpret_cast<const uint8_t*>(&measCharUUID16), 2);
intervalChar.props = whiteboard::MakeArray<WB_RES::GattProperty>( intervalCharProps, 2);
intervalChar.uuid = whiteboard::MakeArray<uint8_t>( reinterpret_cast<const uint8_t*>(&intervalCharUUID16), 2);
intervalChar.initial_value = whiteboard::MakeArray<uint8_t>( reinterpret_cast<const uint8_t*>(&mMeasIntervalSecs), 2);
#ifdef CURRENT_TIME_SVC
timeChar.props = whiteboard::MakeArray<WB_RES::GattProperty>( timeCharProps, 3);
timeChar.uuid = whiteboard::MakeArray<uint8_t>( reinterpret_cast<const uint8_t*>(&timeCharUUID16), 2);
timeChar.initial_value = whiteboard::MakeArray<uint8_t>( reinterpret_cast<const uint8_t*>(&mTimeSecs), 2);
#endif
// Combine chars to service
customGattThermometerSvc.uuid = whiteboard::MakeArray<uint8_t>( reinterpret_cast<const uint8_t*>(&healthThermometerSvcUUID16), 2);
customGattThermometerSvc.chars = whiteboard::MakeArray<WB_RES::GattChar>(characteristics, 2);
// Create custom service
asyncPost(WB_RES::LOCAL::COMM_BLE_GATTSVC(), AsyncRequestOptions::Empty, customGattThermometerSvc);
#ifdef CURRENT_TIME_SVC
// Combine Time chars to service
customGattTimeSvc.uuid = whiteboard::MakeArray<uint8_t>( reinterpret_cast<const uint8_t*>(&timeSvcUUID16), 2);
customGattTimeSvc.chars = whiteboard::MakeArray<WB_RES::GattChar>(characteristicsTime, 1);
// Create custom service
asyncPost(WB_RES::LOCAL::COMM_BLE_GATTSVC(), AsyncRequestOptions::Empty, customGattTimeSvc);
#endif
在 onGetResult 我扩展了代码以合并当前时间服务和特征订阅，如下所示：
void CustomGATTSvcClient::onGetResult(whiteboard::RequestId requestId, whiteboard::ResourceId resourceId, whiteboard::Result resultCode, const whiteboard::Value& rResultData)
{
DEBUGLOG("CustomGATTSvcClient::onGetResult");
switch(resourceId.localResourceId)
{
case WB_RES::LOCAL::COMM_BLE_GATTSVC_SVCHANDLE::LID:
{
const WB_RES::GattSvc &svc = rResultData.convertTo<const WB_RES::GattSvc &>();
for (size_t i=0; i<svc.chars.size(); i++) {
const WB_RES::GattChar &c = svc.chars[i];
uint16_t uuid16 = *reinterpret_cast<const uint16_t*>(&(c.uuid[0]));
if(uuid16 == measCharUUID16)
mMeasCharHandle = c.handle.hasValue() ? c.handle.getValue() : 0;
else if(uuid16 == intervalCharUUID16)
mIntervalCharHandle = c.handle.hasValue() ? c.handle.getValue() : 0;
#ifdef CURRENT_TIME_SVC
else if(uuid16 == timeCharUUID16)
mTimeCharHandle = c.handle.hasValue() ? c.handle.getValue() : 0;
#endif
}
if (!mIntervalCharHandle || !mMeasCharHandle)
{
DEBUGLOG("ERROR: Not all chars were configured!");
return;
}
#ifdef CURRENT_TIME_SVC
if (!mTimeCharHandle)
{
DEBUGLOG("ERROR: Not all chars were configured!");
return;
}
#endif
char pathBuffer[32]= {'\0'};
snprintf(pathBuffer, sizeof(pathBuffer), "/Comm/Ble/GattSvc/%d/%d", mTemperatureSvcHandle, mIntervalCharHandle);
getResource(pathBuffer, mIntervalCharResource);
snprintf(pathBuffer, sizeof(pathBuffer), "/Comm/Ble/GattSvc/%d/%d", mTemperatureSvcHandle, mMeasCharHandle);
getResource(pathBuffer, mMeasCharResource);
#ifdef CURRENT_TIME_SVC
snprintf(pathBuffer, sizeof(pathBuffer), "/Comm/Ble/GattSvc/%d/%d", mTimeSvcHandle, mTimeCharHandle);
getResource(pathBuffer, mTimeCharResource);
#endif
// Subscribe to listen to intervalChar notifications (someone writes new value to intervalChar)
asyncSubscribe(mIntervalCharResource, AsyncRequestOptions::Empty);
// Subscribe to listen to measChar notifications (someone enables/disables the INDICATE characteristic)
asyncSubscribe(mMeasCharResource, AsyncRequestOptions::Empty);
#ifdef CURRENT_TIME_SVC
// Subscribe to listen to timeChar notifications (someone writes new value to timeChar)
asyncSubscribe(mTimeCharResource, AsyncRequestOptions::Empty);
#endif
}
break;
case WB_RES::LOCAL::MEAS_TEMP::LID:
{
// Temperature result or error
if (resultCode == whiteboard::HTTP_CODE_OK)
{
WB_RES::TemperatureValue value = rResultData.convertTo<WB_RES::TemperatureValue>();
float temperature = value.measurement;
// Convert K to C
temperature -= 273.15;
// Return data
//uint8_t buffer[5]; // 1 byte or flags, 4 for FLOAT "in Celsius" value
uint8_t buffer[5];
buffer[0]=0;
// convert normal float to IEEE-11073 "medical" FLOAT type into buffer
floatToFLOAT(temperature, &buffer[1]);
// Write the result to measChar. This results INDICATE to be triggered in GATT service
WB_RES::Characteristic newMeasCharValue;
newMeasCharValue.bytes = whiteboard::MakeArray<uint8_t>(buffer, sizeof(buffer));
asyncPut(WB_RES::LOCAL::COMM_BLE_GATTSVC_SVCHANDLE_CHARHANDLE(), AsyncRequestOptions::Empty, mTemperatureSvcHandle,
mMeasCharHandle, newMeasCharValue);
}
}
break;
#ifdef CURRENT_TIME_SVC
case WB_RES::LOCAL::TIME::LID:
{
// Return with the RTC Time
if (resultCode == whiteboard::HTTP_CODE_OK)
{
WB_RES::DetailedTime value = rResultData.convertTo<WB_RES::DetailedTime>();
int64 tm = value.utcTime;
uint8_t buffer[2];
// Could have an endian issue here, will have to check once connection works
buffer[0] - (tm&0xFF00)>>8;
buffer[1] = tm &0xFF;
// Here we need to get the current time and then Put it back to the device connected
WB_RES::Characteristic newTimeCharValue;
newTimeCharValue.bytes = whiteboard::MakeArray<uint8_t>(buffer, sizeof(buffer));
asyncPut(WB_RES::LOCAL::COMM_BLE_GATTSVC_SVCHANDLE_CHARHANDLE(), AsyncRequestOptions::Empty, mTimeSvcHandle,
mTimeCharHandle, newTimeCharValue);
}
}
break;
#endif
}
}
我在 onGetResult 中添加了时间本地资源，因为我仍然不确定如何从 pod 中“获取”RTC 时间。如何访问 /Time 资源？
onNotify 修改如下：
void CustomGATTSvcClient::onNotify(whiteboard::ResourceId resourceId, const whiteboard::Value& value, const whiteboard::ParameterList& rParameters)
{
switch(resourceId.localResourceId)
{
case WB_RES::LOCAL::COMM_BLE_GATTSVC_SVCHANDLE_CHARHANDLE::LID:
{
WB_RES::LOCAL::COMM_BLE_GATTSVC_SVCHANDLE_CHARHANDLE::SUBSCRIBE::ParameterListRef parameterRef(rParameters);
if (parameterRef.getCharHandle() == mIntervalCharHandle)
{
const WB_RES::Characteristic &charValue = value.convertTo<const WB_RES::Characteristic &>();
uint16_t interval = *reinterpret_cast<const uint16_t*>(&charValue.bytes[0]);
DEBUGLOG(": mMeasCharResource: len: %d, new interval: %d", charValue.bytes.size(), interval);
// Update the interval
if (interval >= 1 && interval <= 65535)
mMeasIntervalSecs = interval;
// restart timer if exists
if (mMeasurementTimer != whiteboard::ID_INVALID_TIMER) {
stopTimer(mMeasurementTimer);
mMeasurementTimer = startTimer(mMeasIntervalSecs*1000, true);
}
}
else if (parameterRef.getCharHandle() == mMeasCharHandle)
{
const WB_RES::Characteristic &charValue = value.convertTo<const WB_RES::Characteristic &>();
bool bNotificationsEnabled = charValue.notifications.hasValue() ? charValue.notifications.getValue() : false;
DEBUGLOG(": mMeasCharHandle. bNotificationsEnabled: %d", bNotificationsEnabled);
// Start or stop the timer
if (mMeasurementTimer != whiteboard::ID_INVALID_TIMER)
{
stopTimer(mMeasurementTimer);
mMeasurementTimer = whiteboard::ID_INVALID_TIMER;
}
if (bNotificationsEnabled)
mMeasurementTimer = startTimer(mMeasIntervalSecs*1000, true);
}
#ifdef CURRENT_TIME_SVC
else if (parameterRef.getCharHandle() == mTimeCharHandle)
{
// Received Time information!
const WB_RES::Characteristic &charValue = value.convertTo<const WB_RES::Characteristic &>();
uint16_t tm = *reinterpret_cast<const uint16_t*>(&charValue.bytes[0]);
DEBUGLOG(": mMeasCharResource: len: %d, new interval: %d", charValue.bytes.size(), tm);
// Update the interval
mTimeSecs = tm;
}
#endif
}
break;
}
}
到目前为止，我认为代码应该是正确的并且可以工作，但是我对 onPostResult 的最后一段代码有疑问：
void CustomGATTSvcClient::onPostResult(whiteboard::RequestId requestId, whiteboard::ResourceId resourceId, whiteboard::Result resultCode, const whiteboard::Value& rResultData)
{
DEBUGLOG("CustomGATTSvcClient::onPostResult: %d", resultCode);
if (resultCode == whiteboard::HTTP_CODE_CREATED) {
#if 1
// This is the code that I propose using when having more than one service but it doesn't seem to work.
const WB_RES::GattSvc &svc = rResultData.convertTo<const WB_RES::GattSvc &>();
uint16_t uuid16 = *reinterpret_cast<const uint16_t*>(&(svc.uuid[0]));
if(uuid16 == healthThermometerSvcUUID16) {
mTemperatureSvcHandle = (int32_t)rResultData.convertTo<uint16_t>();
DEBUGLOG("Custom Gatt service was created. handle: %d", mTemperatureSvcHandle);
asyncGet(WB_RES::LOCAL::COMM_BLE_GATTSVC_SVCHANDLE(), AsyncRequestOptions::Empty, mTemperatureSvcHandle);
}
#ifdef CURRENT_TIME_SVC
else if(uuid16 == timeSvcUUID16) {
mTimeSvcHandle = (int32_t)rResultData.convertTo<uint16_t>();
DEBUGLOG("Custom Gatt service was created. handle: %d", mTimeSvcHandle);
asyncGet(WB_RES::LOCAL::COMM_BLE_GATTSVC_SVCHANDLE(), AsyncRequestOptions::Empty, mTimeSvcHandle);
}
#endif
#else
// This is the code that does work with a single Service but is doesn't work as soon as I add a second service.
// Custom Gatt service was created
mTemperatureSvcHandle = (int32_t)rResultData.convertTo<uint16_t>();
DEBUGLOG("Custom Gatt service was created. handle: %d", mTemperatureSvcHandle);
// Request more info about created svc so we get the char handles
asyncGet(WB_RES::LOCAL::COMM_BLE_GATTSVC_SVCHANDLE(), AsyncRequestOptions::Empty, mTemperatureSvcHandle);
#endif
}
}
你会看到我在这段代码中有一个#if 1 .. (code1) .. #else .. (code2) .. #endif。第一个#if 1 部分（code1）中的代码是我编写的用于与代码创建的两个 GATT 服务一起使用的代码。我觉得既然有两个服务，就必须进行测试（使用服务 UUID）来确定正在处理哪个服务。#else (code2)之后的代码来自于刚刚使用 health temp 服务的原始示例代码。
当我使用(code1)编译时，一切都编译得很好，但我似乎无法订阅健康温度服务。当我切换到使用(code2)时，健康温度服务工作正常，我可以毫无问题地订阅它。
为了测试 GATT 接口，我使用了蓝牙低功耗浏览器 Bluetility。https://github.com/jnross/Bluetility
我的问题如下：
- 我所有的代码都编译得很好，但是一旦我使用（code1），我就无法订阅并让 Health Temp Service 工作。我究竟做错了什么？ (code2)不能使用多个服务，因为它仅适用于 Health Temp 服务。
- 我已经开始实现当前时间服务，但在我修复上面的 Q1 之前，不确定如何实现代码来获取和设置当前时间。
- 一旦成功完成上述操作，我将开始弄清楚如何添加另一个服务来访问加速度计资源（“/Meas/Acc/13”），并使用数据记录器存储加速度计数据和日志以提取它在同一个 GATT 服务中。
如果任何人能够为我指明实现最终目标的正确道路，我将不胜感激。预先感谢。