When 'ble_nus_data_send()' run, NRF_ERROR_INVALID_STATE is output

[schosdas]

Hello
I am using sdk17.0.2 and nrf52840.

I used nrf52832 to combine ble_app_uart and crypto_aes_ctr codes.  And now I'm going to move the code to nrf52840.

However, there is a new problem that has not existed before.  An error 'nrf_error_invalid_state' is output when data is sent to the app via 'bl_nus_data_send'.

        //test
        char app_test[100];
        int test_value = 5;
        
        if(connection_state == 1)
        {
          test_value++;

          sprintf(app_test, "%d", test_value); 
          uint16_t length_test_valuel = strlen(app_test);

          err_code = ble_nus_data_send(&m_nus, &app_test, &length_test_valuel, m_conn_handle);
          check_nus_send = err_code;
          if ((err_code != NRF_ERROR_INVALID_STATE) && 
                (err_code != NRF_ERROR_RESOURCES) &&
                (err_code != NRF_ERROR_NOT_FOUND) &&
                (err_code != BLE_ERROR_GATTS_SYS_ATTR_MISSING)) 
                {
                    APP_ERROR_CHECK(err_code);
                    NRF_LOG_INFO("OK");
                }

          else
            NRF_LOG_INFO("Fail");

          NRF_LOG_INFO("%d", check_nus_send); //err_code : NRF_ERROR_INVALID_STATE(Invalid state, operation disallowed in this state)

          nrf_delay_ms(2000);
        }

When I modified the existing code to nrf52840, I modified the pca10056, softdevice in the settings.  Are there any additional changes to make when modifying from nrf52832 to nrf52840?

Thank you.

[Otso Jousimaa]

First thing that comes to my mind: Is some other device connected to your PCA10056 and registered to the notifications of TX characteristic? I have spent quite a bit of time debugging something that turns out to be caused by forgetting to register to notifications :) 

[schosdas]

Hello, Otso.

thank you for your answer!

How can I check the notification registration of TX that you mentioned?

Thank you!

[Otso Jousimaa]

It depends on your receiver. In nRF Connect app for smart phones there's icon with 3 arrows if I recall correctly, you need to click it. If you have some other app / device it depends on what it is

[schosdas]

Oh, of course the notification on the app is on.

   

And in the debug of the app, things about the connection and notification are printed, but no data is coming in through TX.

[Susheel Nuguru]

The documentation for this very important function is pretty clear.

NRF_ERROR_INVALID_STATE	

One or more of the following is true:
Invalid Connection State
Notifications and/or indications not enabled in the CCCD
An ATT_MTU exchange is ongoing

This API is heavily used in the device so I would double-triple check if the conditions mentioned in your application are true or false before starting to look into anything else.