Unable To WriteValue Or ReadValue On BLE Characteristics #4509

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Unable to writeValue or readValue on BLE characteristics #4509New issueCopy linkNew issueCopy linkClosedClosedUnable to writeValue or readValue on BLE characteristics#4509Copy link

Description

whc2001opened on Nov 9, 2020Issue body actions

Hardware:

Board: ESP32 DevKit V1 Core Installation version: 1.0.4 IDE name: Arduino IDE Flash Frequency: 80Mhz PSRAM enabled: no Upload Speed: 921600 Computer OS: Windows 10

Description:

I tried to use the BLEClient to communicate with my camera. The camera requires pairing before doing anything, so I tried to use nRFConnect app on my Android phone. When not paired, you can discover all the services and characteristics, but if you try to access (read/write) any characteristic, the pairing prompt will appear on the camera screen and you would need to accept it to successfully read/write the value. I can discover the services and characteristics using BLEClient, but absolutely nothing happens when I tried to read or write the characteristics. There is no pairing prompt on camera screen, reading always return empty string and writting just nothing at all.

Sketch: (removed the searching and doing other actions part)

... /* BLE device found handler */ class BleAdvertisedDeviceHandler: public BLEAdvertisedDeviceCallbacks { void onResult(BLEAdvertisedDevice advertisedDevice) { Serial.print("BLE Advertised Device found: "); Serial.println(advertisedDevice.toString().c_str()); if(advertisedDevice.getAddress().equals(cameraMacAddress)) { bleScanner->stop(); cameraDevice = new BLEAdvertisedDevice(advertisedDevice); connectState = FOUND_BLE_DEVICE; } } }; bool Connect() { cameraConnection = BLEDevice::createClient(); cameraConnection->setClientCallbacks(new BleConnectionHandler()); cameraConnection->connect(cameraDevice); Serial.println("Connected"); // Get location service BLERemoteService* locationService = cameraConnection->getService(locationServiceUuid); if (locationService == nullptr) { Serial.println("ERROR: No specified service"); cameraConnection->disconnect(); return false; } Serial.println("Location service found"); // Get location read parameter characteristic locationCharaRead = locationService->getCharacteristic(locationCharaReadUuid); if (locationCharaRead == nullptr) { Serial.println("ERROR: No specified characteristic"); cameraConnection->disconnect(); return false; } Serial.println("Location read parameter characteristic found"); Serial.print("Handle=0x"); Serial.print(locationCharaRead->getHandle(), HEX); Serial.print(" CanRead="); Serial.print(locationCharaRead->canRead()); Serial.print(" CanWrite="); Serial.println(locationCharaRead->canWrite()); // Get location write coordinate characteristic locationCharaWrite = locationService->getCharacteristic(locationCharaWriteUuid); if (locationCharaWrite == nullptr) { Serial.println("ERROR: No specified characteristic"); cameraConnection->disconnect(); return false; } Serial.println("Location write coordinate characteristic found"); Serial.print("Handle=0x"); Serial.print(locationCharaWrite->getHandle(), HEX); Serial.print(" CanRead="); Serial.print(locationCharaWrite->canRead()); Serial.print(" CanWrite="); Serial.println(locationCharaWrite->canWrite()); // Try to read the characteristic Serial.print(locationCharaRead->readValue().c_str()); return true; } ...

Debug Messages:

[V][BLEUtils.cpp:951] gattClientEventTypeToString(): Unknown GATT Client event type: 18 [V][BLEUtils.cpp:1283] dumpGattClientEvent(): GATT Event: Unknown [V][BLERemoteService.cpp:162] retrieveCharacteristics(): >> getCharacteristics() for service: 8000dd00-dd00-ffff-ffff-ffffffffffff [V][BLEUtils.cpp:951] gattClientEventTypeToString(): Unknown GATT Client event type: 18 [D][BLERemoteService.cpp:193] retrieveCharacteristics(): Found a characteristic: Handle: 42, UUID: 0000dd01-0000-1000-8000-00805f9b34fb [D][BLEClient.cpp:158] gattClientEventHandler(): gattClientEventHandler [esp_gatt_if: 4] ... Unknown [V][BLERemoteCharacteristic.cpp:36] BLERemoteCharacteristic(): >> BLERemoteCharacteristic: handle: 42 0x42, uuid: 0000dd01-0000-1000-8000-00805f9b34fb [V][BLERemoteCharacteristic.cpp:250] retrieveDescriptors(): >> retrieveDescriptors() for characteristic: 0000dd01-0000-1000-8000-00805f9b34fb [D][BLERemoteCharacteristic.cpp:280] retrieveDescriptors(): Found a descriptor: Handle: 43, UUID: 00002902-0000-1000-8000-00805f9b34fb [V][BLERemoteCharacteristic.cpp:294] retrieveDescriptors(): << retrieveDescriptors(): Found 1 descriptors. [V][BLERemoteCharacteristic.cpp:45] BLERemoteCharacteristic(): << BLERemoteCharacteristic [D][BLERemoteService.cpp:193] retrieveCharacteristics(): Found a characteristic: Handle: 45, UUID: 0000dd11-0000-1000-8000-00805f9b34fb [V][BLERemoteCharacteristic.cpp:36] BLERemoteCharacteristic(): >> BLERemoteCharacteristic: handle: 45 0x45, uuid: 0000dd11-0000-1000-8000-00805f9b34fb [V][BLERemoteCharacteristic.cpp:250] retrieveDescriptors(): >> retrieveDescriptors() for characteristic: 0000dd11-0000-1000-8000-00805f9b34fb [E][BLERemoteCharacteristic.cpp:274] retrieveDescriptors(): esp_ble_gattc_get_all_descr: Unknown [V][BLERemoteCharacteristic.cpp:294] retrieveDescriptors(): << retrieveDescriptors(): Found 0 descriptors. [V][BLERemoteCharacteristic.cpp:45] BLERemoteCharacteristic(): << BLERemoteCharacteristic [D][BLERemoteService.cpp:193] retrieveCharacteristics(): Found a characteristic: Handle: 47, UUID: 0000dd21-0000-1000-8000-00805f9b34fb [V][BLERemoteCharacteristic.cpp:36] BLERemoteCharacteristic(): >> BLERemoteCharacteristic: handle: 47 0x47, uuid: 0000dd21-0000-1000-8000-00805f9b34fb [V][BLERemoteCharacteristic.cpp:250] retrieveDescriptors(): >> retrieveDescriptors() for characteristic: 0000dd21-0000-1000-8000-00805f9b34fb [E][BLERemoteCharacteristic.cpp:274] retrieveDescriptors(): esp_ble_gattc_get_all_descr: Unknown [V][BLERemoteCharacteristic.cpp:294] retrieveDescriptors(): << retrieveDescriptors(): Found 0 descriptors. [V][BLERemoteCharacteristic.cpp:45] BLERemoteCharacteristic(): << BLERemoteCharacteristic [V][BLERemoteService.cpp:209] retrieveCharacteristics(): << getCharacteristics() Location read parameter characteristic found Handle=0x2F CanRead=1 CanWrite=0 Location write coordinate characteristic found Handle=0x2D CanRead=0 CanWrite=1 [V][BLERemoteCharacteristic.cpp:398] readValue(): >> readValue(): uuid: 0000dd21-0000-1000-8000-00805f9b34fb, handle: 47 0x2f [D][FreeRTOS.cpp:189] take(): Semaphore taking: name: ReadCharEvt (0x3ffdfab0), owner: <N/A> for readValue [D][FreeRTOS.cpp:198] take(): Semaphore taken: name: ReadCharEvt (0x3ffdfab0), owner: readValue [V][FreeRTOS.cpp:63] wait(): >> wait: Semaphore waiting: name: ReadCharEvt (0x3ffdfab0), owner: readValue for readValue [V][BLEUtils.cpp:951] gattClientEventTypeToString(): Unknown GATT Client event type: 3 [D][BLEDevice.cpp:148] gattClientEventHandler(): gattClientEventHandler [esp_gatt_if: 4] ... Unknown [V][BLEUtils.cpp:951] gattClientEventTypeToString(): Unknown GATT Client event type: 3 [V][BLEUtils.cpp:1283] dumpGattClientEvent(): GATT Event: Unknown [V][BLEUtils.cpp:951] gattClientEventTypeToString(): Unknown GATT Client event type: 3 [D][BLEClient.cpp:158] gattClientEventHandler(): gattClientEventHandler [esp_gatt_if: 4] ... Unknown [V][FreeRTOS.cpp:143] give(): Semaphore giving: name: ReadCharEvt (0x3ffdfab0), owner: readValue [V][FreeRTOS.cpp:77] wait(): << wait: Semaphore released: name: ReadCharEvt (0x3ffdfab0), owner: <N/A> [V][BLERemoteCharacteristic.cpp:426] readValue(): << readValue(): length: 0

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