nano 33 iot, BLE, central, number of peripheral connections

hommes · February 27, 2020, 5:15pm

I want to connect a nano 33 iot acting as a central via BLE to 5 peripherals, but unfortunately only 3 peripherals can be connected. Is this a hardware restriction or can I increase the number of connections by setting some prameters?

pert · February 27, 2020, 8:07pm

I see this in the ArduinoBLE library source code:

github.com

arduino-libraries/ArduinoBLE/blob/1.1.2/src/utility/ATT.h#L32


      
          
          
#include <Arduino.h>
          
          
#include "BLEDevice.h"
          
          
#define ATT_CID       0x0004
          
          
#ifdef DM_CONN_MAX
          #define ATT_MAX_PEERS DM_CONN_MAX // Mbed + Cordio
          #else
          #define ATT_MAX_PEERS 3
          #endif
          
          
class BLERemoteDevice;
          
          
class ATTClass {
          public:
            ATTClass();
            virtual ~ATTClass();
          
          
  void setMaxMtu(uint16_t maxMtu);

#define ATT_MAX_PEERS 3

I suspect that's the source of the limitation. Try editing that line of the library and see if it makes a difference. If you want detailed instructions for how to do that, I'm happy to provide them.

hommes · February 29, 2020, 2:55pm

Yes, that's the source of the limitation. Now I can connect to 5 peripherals. Thank you very much.

pert · February 29, 2020, 2:58pm

You're welcome. I'm glad to hear it's working now. Enjoy!
Per

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nano 33 iot, BLE, central, number of peripheral connections

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