update characteristic size to match gatt specifications

update characteristic size to match gatt specifications

format

add specification links

update order of features to match actual specification

Author: matthewshirley

include/BLE_Cycling_Power_Service.h

@@ -21,4 +21,5 @@ class BLE_Cycling_Power_Service {
   BLECharacteristic *cyclingPowerMeasurementCharacteristic;
   BLECharacteristic *cyclingPowerFeatureCharacteristic;
   BLECharacteristic *sensorLocationCharacteristic;
-};
+  byte cpFeature[4] = {0, 0, 0, 0};
+};

include/BLE_Cycling_Speed_Cadence.h

@@ -21,4 +21,5 @@ class BLE_Cycling_Speed_Cadence {
   BLECharacteristic *cscMeasurement;
   BLECharacteristic *cscFeature;
   BLECharacteristic *cscControlPoint;
+  byte cscFeatureBytes[2] = {0, 0};
 };

include/BLE_Definitions.h

@@ -12,7 +12,7 @@ struct FitnessMachineIndoorBikeDataFlags {
   enum Types : uint16_t {
     MoreDataBit                 = 1U << 0,
     AverageSpeedPresent         = 1U << 1,
-    InstantaneousCadencePresent = 1U << 2,    
+    InstantaneousCadencePresent = 1U << 2,
     AverageCadencePresent       = 1U << 3,
     TotalDistancePresent        = 1U << 4,
     ResistanceLevelPresent      = 1U << 5,
@@ -191,6 +191,27 @@ struct FtmsStatus {
   int length;
 };
 
+// https://www.bluetooth.com/specifications/specs/cpp-1-1-html/
+// See "4.4. Cycling Power Feature"
+struct CyclingPowerFeatureFlags {
+  enum Types : uint32_t {
+    PedalPowerBalanceSupported           = 1U << 0,
+    AccumulatedTorqueSupported           = 1U << 1,
+    WheelRevolutionDataSupported         = 1U << 2,
+    CrankRevolutionDataSupported         = 1U << 3,
+    ExtremeMagnitudesSupported           = 1U << 4,
+    ExtremesAnglesSupported              = 1U << 5,
+    TopBottomDeadSpotAnglesSupported     = 1U << 6,
+    AccumulatedEnergySupported           = 1U << 7,
+    ExtremeTorquesSupported              = 1U << 8,
+    OffsetCompensationIndicatorSupported = 1U << 9,
+  };
+};
+
+inline CyclingPowerFeatureFlags::Types operator|(CyclingPowerFeatureFlags::Types a, CyclingPowerFeatureFlags::Types b) {
+  return static_cast<CyclingPowerFeatureFlags::Types>(static_cast<int>(a) | static_cast<int>(b));
+}
+
 class CyclingPowerMeasurement {
  public:
   // Flags definition as per specification
@@ -256,6 +277,21 @@ class CyclingPowerMeasurement {
   }
 };
 
+// https://www.bluetooth.com/specifications/specs/cscs-1-0/
+// See "3.2. CSC Feature"
+struct CyclingSpeedCadenceFeatureFlags {
+  enum Types : uint16_t {
+    WheelRevolutionDataSupported     = 1U << 0,
+    CrankRevolutionDataSupported     = 1U << 1,
+    MultipleSensorLocationsSupported = 1U << 2
+    // 3-15: Reserved for Future Use
+  };
+};
+
+inline CyclingSpeedCadenceFeatureFlags::Types operator|(CyclingSpeedCadenceFeatureFlags::Types a, CyclingSpeedCadenceFeatureFlags::Types b) {
+  return static_cast<CyclingSpeedCadenceFeatureFlags::Types>(static_cast<int>(a) | static_cast<int>(b));
+}
+
 class CscMeasurement {
  public:
   // Flags definition as per specification
@@ -305,4 +341,4 @@ class CscMeasurement {
 
     return data;
   }
-};
+};

src/BLE_Cycling_Power_Service.cpp

@@ -16,7 +16,15 @@ void BLE_Cycling_Power_Service::setupService(NimBLEServer *pServer, MyCallbacks
   cyclingPowerFeatureCharacteristic     = pPowerMonitor->createCharacteristic(CYCLINGPOWERFEATURE_UUID, NIMBLE_PROPERTY::READ);
   sensorLocationCharacteristic          = pPowerMonitor->createCharacteristic(SENSORLOCATION_UUID, NIMBLE_PROPERTY::READ);
   byte cpsLocation[1]                   = {0b0101};    // sensor location 5 == left crank
-  byte cpFeature[1]                     = {0b001100};  // crank information & wheel revolution data present
+
+  CyclingPowerFeatureFlags::Types cpFeatureFlags = CyclingPowerFeatureFlags::WheelRevolutionDataSupported |
+                                                   CyclingPowerFeatureFlags::CrankRevolutionDataSupported;
+
+  cpFeature[0] = static_cast<uint8_t>(cpFeatureFlags & 0xFF);
+  cpFeature[1] = static_cast<uint8_t>((cpFeatureFlags >> 8) & 0xFF);
+  cpFeature[2] = static_cast<uint8_t>((cpFeatureFlags >> 16) & 0xFF);
+  cpFeature[3] = static_cast<uint8_t>((cpFeatureFlags >> 24) & 0xFF);
+
   cyclingPowerFeatureCharacteristic->setValue(cpFeature, sizeof(cpFeature));
   sensorLocationCharacteristic->setValue(cpsLocation, sizeof(cpsLocation));
   cyclingPowerMeasurementCharacteristic->setCallbacks(chrCallbacks);
@@ -57,4 +65,4 @@ void BLE_Cycling_Power_Service::update() {
 
   logCharacteristic(logBuf, kLogBufCapacity, &byteArray[0], byteArrayLength, CYCLINGPOWERSERVICE_UUID, cyclingPowerMeasurementCharacteristic->getUUID(),
                     "CPS(CPM)[ CD(%.2f) PW(%d) ]", cadence > 0 ? fmodf(cadence, 1000.0) : 0, power % 10000);
-}
+}

src/BLE_Cycling_Speed_Cadence.cpp

@@ -14,8 +14,14 @@ void BLE_Cycling_Speed_Cadence::setupService(NimBLEServer *pServer, MyCallbacks
   pCyclingSpeedCadenceService = pServer->createService(CSCSERVICE_UUID);
   cscMeasurement              = pCyclingSpeedCadenceService->createCharacteristic(CSCMEASUREMENT_UUID, NIMBLE_PROPERTY::NOTIFY);
   cscFeature                  = pCyclingSpeedCadenceService->createCharacteristic(CSCFEATURE_UUID, NIMBLE_PROPERTY::READ);
-  byte cscFeatureFlags[1]     = {0b11};
-  cscFeature->setValue(cscFeatureFlags, sizeof(cscFeatureFlags));
+  
+  CyclingSpeedCadenceFeatureFlags::Types cscFeatureFlags = CyclingSpeedCadenceFeatureFlags::WheelRevolutionDataSupported | 
+                                                           CyclingSpeedCadenceFeatureFlags::CrankRevolutionDataSupported;
+
+  cscFeatureBytes[0] = static_cast<uint8_t>(cscFeatureFlags & 0xFF);
+  cscFeatureBytes[1] = static_cast<uint8_t>((cscFeatureFlags >> 8) & 0xFF);
+
+  cscFeature->setValue(cscFeatureBytes, sizeof(cscFeatureBytes));
   cscMeasurement->setCallbacks(chrCallbacks);
   pCyclingSpeedCadenceService->start();
 }