ATT_MTU_Throughput how does NRF_ERROR_RESOURCES work?

RE: ATT_MTU_Throughput how does NRF_ERROR_RESOURCES work?

Den — Wed, 31 Jul 2019 10:37:53 GMT

So once busy = true is set, it waits for the BLE_GATTS_EVT_HVN_TX_COMPLETE event in sleep. Now it makes sense. I missed that bit. Thanks very much for the clarification Einar👍

RE: ATT_MTU_Throughput how does NRF_ERROR_RESOURCES work?

Einar Thorsrud — Wed, 31 Jul 2019 07:15:58 GMT

Hi,

[quote user="Denin"]The thing I do not understand is; when we set busy = true and get out of the while loop, the code has to wait somewhere until BLE_GATTS_EVT_HVN_TX_COMPLETE event occurs and on_tx_complete() is called, is this right? Where does it wait?[/quote]

There is no special logic needed for waiting in this case, since the BLE stack is event-driven. It just sets the busy flag to true, and breaks out of the loop, and then out of the char_notification_send(). Then the char_notification_send() is called again in the handling of the BLE_GATTS_EVT_HVN_TX_COMPLETE only if busy is true.

After all interrupts are services and nothing else happens, then the main loop will run, which calls idle_state_handle() in main.c of the example. Essentially it will just put the CPU to sleep in this case, waiting for an event/interrupt.

In detail:

static void idle_state_handle(void)
{
    cli_process();

    if (is_test_ready())
    {
        NRF_LOG_INFO("Test started");
        m_run_test = true;
        test_run();
    }

    if (NRF_LOG_PROCESS() == false)
    {
        nrf_pwr_mgmt_run();
    }
}

If a current test is in progress (which will be the case here), then m_run_test is true, so is_test_ready() will return false. Therefore the only thing that happens is first processing of CLI (if needed), then processing of logs if needed. Then the CPU enters sleep by calling nrf_pwr_mgmt_run().

RE: ATT_MTU_Throughput how does NRF_ERROR_RESOURCES work?

Den — Tue, 30 Jul 2019 13:58:27 GMT

Hi Einer,

I guess I mentioned this loop stuff myself in my question already :) The thing I do not understand is; when we set busy = true and get out of the while loop, the code has to wait somewhere until BLE_GATTS_EVT_HVN_TX_COMPLETE event occurs and on_tx_complete() is called, is this right? Where does it wait?

RE: ATT_MTU_Throughput how does NRF_ERROR_RESOURCES work?

Einar Thorsrud — Tue, 30 Jul 2019 13:48:40 GMT

Hi,

The BLE stack and SDK are event-based, so the BLE_GATTS_EVT_HVN_TX_COMPLETE will be received by the BLE event handlers. In the ATT_MTU_Throughput example in SDK 15.3 this is implemented in examples\ble_central_and_peripheral\experimental\ble_app_att_mtu_throughput\amts.c. There you can see that a BLE_GATTS_EVT_HVN_TX_COMPLETE event causes a call to on_tx_complete(), which calls char_notification_send() if the busy flag was set. And then we are back in the loop 🙂