Problem about the max count for the nRF52840-Dongle.

[kevinlei]

Hi Dear Team,

I am using the nRF52840-Dongle and pc-ble-driver-py-0.12.0 for the ble development, while I encounter a problem about the max connection per device.

I use the nRF52840-Dongle to connect to multi-end in parallel, but usually if I have 3 active connections, the next connection will always failed because of the COUNT ERROR:

ERROR:  connect to XXXX err 18-Failed to ble_gap_connect. Error code: 18 - BleCollector.py:222

From the SDK, error code 18 means:

#define 	NRF_ERROR_CONN_COUNT   (NRF_ERROR_BASE_NUM + 18)
 	Maximum connection count exceeded. 

it seems that the max connections for the nRF52840 is 3, all more than 3 will be rejected by the connection exceed error, I believe the ble connect would not to be only 3, but  I have no clue to extend the max count. Could you please tell me how to make the nRF able to connect to more than 3  end-devices simultaneously? Thank you very much.

BTW, I tried to modify the gatt_config but didn't work:

            gatt_cfg = BLEConfigConnGatt()
            gatt_cfg.att_mtu = self.adapter.default_mtu
            gatt_cfg.tag = CFG_TAG
            gatt_cfg.conn_count = 8
            gatt_cfg.event_length = 8
            self.adapter.driver.ble_cfg_set(BLEConfig.conn_gatt, gatt_cfg)

            self.adapter.driver.ble_enable()

[tesc]

Hi,

The connectivity firmware should be capable of higher connection counts than 3, but configuring the number of connections cannot be done the way that you tried with gatt_cfg. Unfortunately I have not figured out how to do it from pc-ble-driver-py yet, but hopefully I can get back to you with a solution in a day or two.

Regards,
Terje

[kevinlei]

Thank you for your efforts, I am looking forward your reply. Thanks a lot.

[tesc]

Hi,

Connection count and event length are GAP configurations, not GATT configurations. You can set GAP configurations like this:

gap_cfg = BLEConfigConnGap()
gap_cfg.conn_count = 8
gap_cfg.event_length = 8
self.adapter.driver.ble_cfg_set(BLEConfig.conn_gap, gap_cfg)

Regards,
Terje