Xiao BLE nRF52840 flaky scanning

Products & Technology XIAO
2

same here, the Xiao BLE nRF52840 Receiver Central freezes after 15-30min !!!

I am using ArduinoBLE library, normal as usual.

The sender is off most of the time and will only connect and send sensor data about once or twice a day. I try to have the receiver active 24h. But it freezes after 15-30min.

Here is my receiver Central code:

#include <ArduinoBLE.h>

char* PERIPHERAL_LOCAL_NAME = "SOME PERIPHERAL NAME";
#define BLE_UUID_SENSOR_DATA_SERVICE    "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx"
#define BLE_UUID_MULTI_SENSOR_DATA      "yyyyyyyy-yyyy-yyyy-yyyy-yyyyyyyyyyyy"

#define BAUDRATE                        115200
#define UPDATE_INTERVALL                10
#define BLE_POLL_INTERVALL              5

uint64_t previousMillis = 0;

void setup() {
    
    Serial.begin(BAUDRATE);
    delay(2000);
    
    previousMillis = millis();

    BLE.begin();

    BLE.scanForUuid(BLE_UUID_SENSOR_DATA_SERVICE);
}

void loop() {
        
    unsigned long currentMillis = millis();
    
    if (currentMillis - previousMillis > UPDATE_INTERVALL) {
        
        previousMillis = currentMillis;

        BLE.scanForUuid(BLE_UUID_SENSOR_DATA_SERVICE);
        
        BLEDevice peripheral = BLE.available();

        if (peripheral) {
            
            if (peripheral.localName() != PERIPHERAL_LOCAL_NAME) {
                return;
            }

            BLE.stopScan();

            explorePeripheral(peripheral);
        }
    }
}

bool explorePeripheral(BLEDevice peripheral) {
    
    if (!peripheral.connect()) {
        return false;
    }
  
    if (!peripheral.discoverAttributes()) {
        peripheral.disconnect();
        return false;
    }
  
    BLECharacteristic multiSensorDataCharacteristic = peripheral.characteristic(BLE_UUID_MULTI_SENSOR_DATA);
    if (!multiSensorDataCharacteristic) {
        peripheral.disconnect();
        return false;
    }
    
    if (!multiSensorDataCharacteristic.canSubscribe()) {
        peripheral.disconnect();
        return false;
    }
    
    if (!multiSensorDataCharacteristic.subscribe()) {
        peripheral.disconnect();
        return false;
    }
  
    while (peripheral.connected()) { 

        unsigned long currentMillis = millis();
        
        if (currentMillis - previousMillis > BLE_POLL_INTERVALL) {

            previousMillis = currentMillis;
        
            BLE.poll();

            if (multiSensorDataCharacteristic.valueUpdated()) {

                multiSensorDataCharacteristic.readValue(...);
            }

            // if (peripheral.rssi() != 0) {
            //     digitalWrite(RSSI_OK_LED_PIN, HIGH);
            // } else {
            //     digitalWrite(RSSI_OK_LED_PIN, LOW); // red alarm LED ON
            // }
        }
    }

    peripheral.disconnect();
    
    return true;
}

I tried to add a periodic BLE.end(); followed by a BLE.begin(); every 10 seconds because I believed this might help. But no change.

It seems that only a module RESET will solve the problem.

However, in my application I would like to have the receiver listen during 24 hours (and never power it off or reset).

What could be the issue of the freeze ?