Timeslot extension

[Tong Yu]

Hello all,

After several tests about extending Timeslot, I have some questions.

1. I found out that the Timeslot will keep extending automatically after a successful extension, right?

2. If I am right about the first question, then about the extension length, in my code, extend.length_us = 200, and the "callback_action" will be set to "NRF_RADIO_SIGNAL_CALLBACK_ACTION_END" if the total length above 120,000,000 us, so that the Timeslot will end rather than exceed the 128s limit and extend failed.
   I used the "NRF_LOG_INFO" printed the result:
   :INFO:NRF_EVT_RADIO_SESSION_IDLE
   :INFO:NRF_EVT_RADIO_SESSION_CLOSED
   :INFO: extend_success_count = 600000
   :INFO: extend_fail_count = 0

    case NRF_RADIO_CALLBACK_SIGNAL_TYPE_EXTEND_SUCCEEDED: 
   
        if(total_timeslot_length >= 120000000)
        {
            signal_callback_return_param.callback_action = NRF_RADIO_SIGNAL_CALLBACK_ACTION_END;
        }else
        {
        total_timeslot_length += 200;
        extend_success_count++;
        }
   
        break;
   
    case NRF_RADIO_CALLBACK_SIGNAL_TYPE_EXTEND_FAILED: 
   
        fail_count++;
   
        break;
   

Also in Timeslot event handler:

    case NRF_EVT_RADIO_SESSION_IDLE:
        
        sd_radio_session_close();
        NRF_LOG_INFO("NRF_EVT_RADIO_SESSION_IDLE\r\n");

        break;

    case NRF_EVT_RADIO_SESSION_CLOSED: 
        
        NRF_LOG_INFO("NRF_EVT_RADIO_SESSION_CLOSED\r\n");
        NRF_LOG_INFO(" extend_success_count            = %d\r\n", extend_success_count);
        NRF_LOG_INFO(" extend_fail_count               = %d\r\n", fail_count);

        break;

But the problem is: the real time about the extension was far less that 120 seconds, only few seconds and as I increase the "extend_length", the real time get even shorter, so where is the problem?

Many thanks!

[Ole Bauck]

You check if you get the callback signal NRF_RADIO_CALLBACK_SIGNAL_TYPE_EXTEND_FAILED or NRF_RADIO_CALLBACK_SIGNAL_TYPE_EXTEND_SUCCEEDED? See the radio timeslot extension example in the SoftDevice specification.

If you try to extend the the timeslot and this will conflict with already scheduled SoftDevice activities of equal or higher priority you will get the extend failed signal. See here and here for more info on the scheduler and the SoftDevice priorities.