Disconnect nrf51822 when the correct connection interval is not negotiated with the phone

RE: Disconnect nrf51822 when the correct connection interval is not negotiated with the phone

Hung Bui — Thu, 11 Aug 2016 08:20:29 GMT

Hi ua,

Yes, but you need to check if it's actually called or not. This will explain why update_timeout_handler() is not called.

It's more important that you find out how the code works and why it didn't work in your case. I would suggest you to add some UART debug trace to get to know what happens.

Basically, the way it works is that depends on whether you set start_on_notify_cccd_handle = BLE_GATT_HANDLE_INVALID or not when init the module, the module will execute conn_params_negotiation() on either BLE_GAP_EVT_CONNECTED or BLE_GATTS_EVT_WRITE (when write to CCCD). If you set start_on_notify_cccd_handle to something, and then never write to CCCD, then connection parameter will never be executed.

Inside conn_params_negotiation() we will check if the current parameter matched with what we want then we will do nothing and notify the main application with BLE_CONN_PARAMS_EVT_SUCCEEDED.

If not, we will start the negotiation process by starting up the timer (if we haven't started) and then in each timer timeout we will send a connection parameter request. We will do it MAX_CONN_PARAMS_UPDATE_COUNT (3) times, before we give up and notify the application that it's failed.

We will also do the same process if we receive a connection parameter update from the phone (BLE_GAP_EVT_CONN_PARAM_UPDATE event).

So you job is to check why it didn't go this way, or if it goes this way but you may want to modify something.

RE: Disconnect nrf51822 when the correct connection interval is not negotiated with the phone

ua09 — Wed, 10 Aug 2016 16:02:24 GMT

I have added the code for conn_params_negotiation in the question.n. I believe the app_start_timer is called in the right position

RE: Disconnect nrf51822 when the correct connection interval is not negotiated with the phone

Hung Bui — Wed, 10 Aug 2016 14:04:58 GMT

Hi ua,

Please double check and see if

err_code = app_timer_start(m_conn_params_timer_id, timeout_ticks, NULL);

is called in conn_params_negotiation(). The timer should be started if m_change_param = false (you are not calling ble_conn_params_change_conn_params() ) and when you are connected, or when CCCD is written (depends on your configuration) or when the central update a new connection parameter.

If you configured the max and min connection interval of 7.5ms and it not what you have when you are connected , the timer should already be started by the code in on_connect() in ble_conn_params.c

RE: Disconnect nrf51822 when the correct connection interval is not negotiated with the phone

ua09 — Wed, 10 Aug 2016 12:04:23 GMT

it means that the correct value is negotitated

RE: Disconnect nrf51822 when the correct connection interval is not negotiated with the phone

Hung Bui — Wed, 10 Aug 2016 11:28:37 GMT

Hi ua,

Could you explain this, I don't understand:

Everytime the correct value is not negotiated, the update_timeout_handler has not been triggered. But when it works the update_timeout_handler is triggered.

What did you mean by when "it works" ?

RE: Disconnect nrf51822 when the correct connection interval is not negotiated with the phone

ua09 — Wed, 10 Aug 2016 10:37:11 GMT

hi, i figured out why the correct connection interval is sometimes not negotiated. Everytime the correct value is not negotiated, the update_timeout_handler has not been triggered. But when it works the update_timeout_handler is triggered. Do you have an idea why it is not triggered sometimes and a possible solution? Thanks

RE: Disconnect nrf51822 when the correct connection interval is not negotiated with the phone

Hung Bui — Wed, 03 Aug 2016 12:35:27 GMT

@ua: Please make sure m_conn_params_timer_id timer is started and update_timeout_handler() is triggered on each timeout.

RE: Disconnect nrf51822 when the correct connection interval is not negotiated with the phone

ua09 — Wed, 03 Aug 2016 11:09:18 GMT

Both max and min are set to 7.5ms

RE: Disconnect nrf51822 when the correct connection interval is not negotiated with the phone

Hung Bui — Wed, 03 Aug 2016 11:03:45 GMT

@ua09: Could you try to debug and see if the update_timeout_handler() is triggered ? If you can provide a sniffer trace it could be very helpful.

Which was the max connection interval and min connection interval you requested ?

RE: Disconnect nrf51822 when the correct connection interval is not negotiated with the phone

ua09 — Tue, 02 Aug 2016 14:59:57 GMT

Hi Thanks for the reply. I removed the if statement ( and changed it in the question as well) and tried to implement this with cp_init.disconnect_on_fail = true; but it still does not work. when a connection interval of 7.5ms is not accepted a default of 48.75ms is accepted and the data slows down

RE: Disconnect nrf51822 when the correct connection interval is not negotiated with the phone

Hung Bui — Tue, 02 Aug 2016 14:21:16 GMT

Hi,

I don't understand why you check for the return code of ble_conn_params_init() and then call disconnect if it's not success.

ble_conn_params_init() is not really the place to check if the connection interval is not accepted by peer device. ble_conn_params_init() is where you configure the parameter with the ble_conn_params.c module. It only configure the parameter locally, and at that moment you don't know if the peer device will accept or reject the request.

What you should do is to configure the disconnect_on_fail parameter. If you set it to true, later when the negotiation is failed, the ble_conn_params.c module will disconnect. Please have a look at the update_timeout_handler() function in the file.

I can see that disconnect_on_fail is already set, did you see the behaviour that the peripheral disconnect after connection parameter update request failed ?