Send packet continuously over nus

[Fiske]

Is it OK  to send multiple packet continuously over nus at below way without waiting for packet transmit complete?

      i=UserUart.RxBuf[1]+2;
           index = 0;
           while(i>0)
           {
             if(i>20)
             {
               err_code = ble_nus_string_send(&m_nus, UserUart.RxBuf+index, 20);
               if (err_code != NRF_ERROR_INVALID_STATE)
               {
                   APP_ERROR_CHECK(err_code);
               }
               i -= 20;
               index += 20;
             }
             else 
             {
               err_code = ble_nus_string_send(&m_nus, UserUart.RxBuf+index, i);
               if (err_code != NRF_ERROR_INVALID_STATE)
               {
                   APP_ERROR_CHECK(err_code);
               }
               i = 0;
               
             }
               
           }

[Hung Bui]

Hi Fiske,

Yes you can. You will receive TX buffer full return code when the buffer is full (7 packets with high bw) and this way keeps the CPU running all the time.

[Turbo J]

Contrary to Hung Bui's answer, your code will not work in case you go over 6 or 7 times 20 bytes.

The ble_nus_string_send() function will return an error code (BLE_ERROR_NO_TX_PACKETS), and your app goes to whatever app_error_handler() you have set up.

You need to handle at least this error indicating that the SD has no more TX buffers left.

[Hung Bui]

You are correct, Turbo. I mentioned about the return code TX buffer full that he need to handle. It's called now BLE_ERROR_NO_TX_PACKETS, was BLE_ERROR_NO_TX_BUFFERS before. And yes, he need to handle that return code and not send it to APP_ERROR_CHECK.

[Fiske]

Can I modify the code to below? Can below code make sure that all packet are deliveried

  i=UserUart.RxBuf[1]+2;
       index = 0;
       while(i>0)
       {
         if(i>20)
         {
           while((err_code = ble_nus_string_send(&m_nus, UserUart.RxBuf+index, 20)) ==BLE_ERROR_NO_TX_PACKETS)
           {           
                      ;
           }
           if (err_code != NRF_ERROR_INVALID_STATE)
           {
               APP_ERROR_CHECK(err_code);
           }
           i -= 20;
           index += 20;
         }
         else 
         {
           while((err_code = ble_nus_string_send(&m_nus, UserUart.RxBuf+index, i))====BLE_ERROR_NO_TX_PACKETS) 
            {

                         ;
            }
           if (err_code != NRF_ERROR_INVALID_STATE)
           {
               APP_ERROR_CHECK(err_code);
           }
           i = 0;

         }

       }