Unable to connect & restart scan

[CydiaBoss]

Now that I got logging up and running, I see that the connection process is timing out on the device I want to connect to. It has the advertising type of indirect advertising (BLE_HCI_ADV_TYPE_ADV_IND), which should still be connectable per the standard. Increasing the timeout also doesn't changes anything. I am able to connect to the device through the nRF Connect App on my phone, so it should be connectable.

Another thing is that after the connection fails, I am not able to restart the scanning process. I get the following error: Unable to scan - connection in progress. I try running cancelConnect() and disconnect() before rerunning the scan's start() command, but still shows the same error. Any ideas on how to fix these issues?

[CydiaBoss]

Here's a portion of my code that is related to the BLE stuff:

#include <Arduino.h> #include <NimBLEDevice.h> // Settings NimBLEScan* pBLEScan; NimBLEClient* pClient; bool isConnected = false; // UUID NimBLEUUID serviceUUID("0000dcba-1212-efde-1523-785fef13d123"); NimBLEUUID configCharacteristicUUID("00000004-1212-efde-1523-785fef13d123"); NimBLEUUID configValueCharacteristicUUID("00000005-1212-efde-1523-785fef13d123"); NimBLEUUID statusCharacteristicUUID("00000006-1212-efde-1523-785fef13d123"); NimBLEUUID commandCharacteristicUUID("0000000b-1212-efde-1523-785fef13d123"); // Characteristics NimBLERemoteCharacteristic* configCharacteristic; NimBLERemoteCharacteristic* configValueCharacteristic; NimBLERemoteCharacteristic* statusCharacteristic; NimBLERemoteCharacteristic* commandCharacteristic; // Data float inlet = 0.0f; float outlet = 0.0f; float dp = 0.0f; bool isFlushing = false; // put function declarations here: void startScan(); bool connectToServer(const NimBLEAdvertisedDevice* address); void pingStatus(); void processSerial(); String handleConfigCommand(String command, bool isGet); // Scan Callback class ScanCallback: public NimBLEScanCallbacks { void onResult(const NimBLEAdvertisedDevice *advertisedDevice) override { // Check Name if (!advertisedDevice->haveName() || advertisedDevice->getName().length() < 4 || advertisedDevice->getName().substr(0, 4) != "ADIX") return; // Debugging Stuff	Serial.println(advertisedDevice->toString().c_str());	Serial.printf("%d\n", advertisedDevice->getAdvType());	Serial.printf("%d\n", advertisedDevice->getAddressType());	Serial.println(advertisedDevice->isScannable()?"1":"0");	Serial.println(advertisedDevice->isLegacyAdvertisement()?"1":"0"); // Start Connection	Serial.println("FNDS");	pBLEScan->stop(); //Scan can be stopped, we found what we are looking for	isConnected = connectToServer(advertisedDevice); // Restart if needed if (!isConnected) startScan();	} }; // Client Callback for handling successful connections class ClientCallback : public NimBLEClientCallbacks { void onConnectFail(NimBLEClient *pClient, int reason) override {	Serial.println("DCNT");	isConnected = false; startScan();	} void onDisconnect(NimBLEClient *pClient, int reason) override {	Serial.println("DCNT");	isConnected = false; startScan();	} }; void setup() {	Serial.begin(115200); NimBLEDevice::init(""); NimBLEDevice::setSecurityAuth(false, false, false);	pBLEScan = NimBLEDevice::getScan(); //create new scan	pBLEScan->setScanCallbacks(new ScanCallback());	pBLEScan->setInterval(50);	pBLEScan->setWindow(50); // less or equal setInterval value	pBLEScan->setActiveScan(true);	pClient = NimBLEDevice::createClient();	pClient->setConnectionParams(12, 12, 0, 250);	pClient->setConnectTimeout(5000);	pClient->setClientCallbacks(new ClientCallback()); // Protect against disconnects	pClient->setSelfDelete(false, false); // Start startScan(); pinMode(LED_BUILTIN, OUTPUT); digitalWrite(LED_BUILTIN, LOW); } void loop() { // Flashing LED Indicator for Scanning if (pBLEScan->isScanning()) digitalWrite(LED_BUILTIN, digitalRead(LED_BUILTIN) ? LOW : HIGH); // LED for Connection else digitalWrite(LED_BUILTIN, isConnected ? HIGH : LOW); // Handle any serial processSerial(); // Ping status pingStatus(); // Delay a bit delay(500); } void startScan() { int countdown = 0; while(!pBLEScan->start(0) && countdown < 5) { delay(1000);	countdown++;	} } bool connectToServer(const NimBLEAdvertisedDevice* pDevice) { // Connection Safety if (pClient->isConnected())	pClient->disconnect(); // Connect to the remove BLE Server. if (!pClient->connect(pDevice)) {	pClient->cancelConnect();	pClient->disconnect();	Serial.println("NCTD"); return false;	} // Obtain a reference to the service we are after in the remote BLE server	NimBLERemoteService* pRemoteService = pClient->getService(serviceUUID); if (pRemoteService == nullptr) {	Serial.println("NSER");	pClient->disconnect(); return false;	} // Obtain a reference to the characteristics in the service of the remote BLE server.	configCharacteristic = pRemoteService->getCharacteristic(configCharacteristicUUID);	configValueCharacteristic = pRemoteService->getCharacteristic(configValueCharacteristicUUID);	statusCharacteristic = pRemoteService->getCharacteristic(statusCharacteristicUUID);	commandCharacteristic = pRemoteService->getCharacteristic(commandCharacteristicUUID); if (configCharacteristic == nullptr || configValueCharacteristic == nullptr || statusCharacteristic == nullptr || commandCharacteristic == nullptr) {	Serial.println("NCHR");	pClient->disconnect(); return false;	} // Success	Serial.println("CNTD"); return true; }

[h2zero]

You should not be calling connect or scan start from the scan result callback, this holds up the stack and is why you are getting those errors. Set a flag or use a queue of sorts to initiate the connection process in a another task, or in loop.

[CydiaBoss]

Thank you so much, that seems to have fix it!