10 Replies Latest reply on Apr 2, 2018 3:17 AM by wangbei325_2776061

    BLE data packet

    wangbei325_2776061

      Hello ,

       

      i wanted to send a data packet from server to client. Because there were two different data types, the uint32 and uint8. I've defined a uint8 array, which had the length 5:

      uint8 sendDataPacket[5];

      in the first 4 array's units, i've saved the uint32: firstly i separated the uint32 into 4 uint8s, and then saved every uint8 in each array unit. The last data type uint8, i saved it in the last array unit of sendDataPacket[5].

       

      After the sending from the server and receiving of the Client, i readed them by using 'CYBLE_GATTC_HANDLE_VALUE_NTF_PARAM_T RX_data = (CYBLE_GATTC_HANDLE_VALUE_NTF_PARAM_T *) eventparam; ' and then saved them in another uint8 receiveDataPacket[5] on the client side.

       

      Unfortunately, i could not read the last uint8 from the receiveDatapacket[5]. The data there was not what i expected.

       

      Could anyone tell me, what was going wrong?

        • 1. Re: BLE data packet
          e.pratt_1639216

          Most likely you are not storing the uint8 into the array for sending in the first place correctly. Try looking at your code to write the values into the notification to see if you are just passing a reference or something. Also, you need to make sure the length of the array for sending the data is set to 5 for it to use all 5 values.

          It would be easier to help if you show us the code in question for sending and receiving the data.

          • 2. Re: BLE data packet
            user_78878863

            An array of length 5 is index from array[0] up to array[4]. When you use array[5], you store the data outside of the array, so it will not be transmitted (because the BLE stack only takes the actual array). When you are unlucky, that memory location holds something important and your code crashes.

            • 3. Re: BLE data packet
              e.pratt_1639216

              It depends on the code itself. He claims to be using 5 for all of the values, which would mean that he allocates space for a 6-byte array (zero-indexed), and the correct length of 5. And consistent access/usage in the code would be fine with this, as the unused byte would just be wasted space. But, yes, if you set the array to size 4 and assign values to array[5], then it will overflow and corrupt RAM space.

              Hence why I was asking if he could give us the source code to see how he is using it, and if there is a pointer/referencing issue or something else.

              • 4. Re: BLE data packet
                user_78878863

                The array declaration is (from the first post):

                uint8 sendDataPacket[5];

                so its clearly only 5 bytes long, and therefore accessing sendDataPacket[5] is not the array anymore.

                • 5. Re: BLE data packet
                  e.pratt_1639216

                  Ah. Oops, I'm wrong. You are right @user_78878863. I was confusing the C notation with VB notation >.<

                  He should be using 0-4 as you stated above. The 5th byte would then be sendDataPacket[4] for reading and writing.

                  PS: VB uses uint8 arrayName[5] to signify an array from 0 to 5 inclusive, which was making me think he was declaring a 6-byte array and using only 5 bytes in it...

                  • 6. Re: BLE data packet
                    wangbei325_2776061

                    On the Server side:

                     

                    I've converted the analog signal to digital signal, this time i used uint16 and uint8, and stored them in the uint8 sendDataPacket[3];

                     

                    1)       uint8 sendDataPacket[3];

                     

                               int16 x= Sensor_ADC_CountsTo_mVolts(0, Sensor_ADC_GetResult16(0)) ;

                               uint16 y=(uint16)x;

                     

                               uint8 buttons_temp = SendButtons8();   // 0b00000010

                     

                               sendDataPacket[0]= (uint8)y;

                               sendDataPacket[1]= (uint8)(y >> 8u);

                               sendDataPacket[2]= (uint8)buttons_temp ;

                     

                    2)        CYBLE_GATTS_HANDLE_VALUE_NTF_T      sendTxDataNtf;

                     

                               sendTxDataNtf.value.val  = sendDataPacket;

                               sendTxDataNtf.value.len  = 1;

                               sendTxDataNtf.attrHandle = CYBLE_SERVER_ACCEL_SERVER_ACCEL_TX_DATA_CHAR_HANDLE;

                               CyBle_GattsNotification(cyBle_connHandle, &sendTxDataNtf);

                     

                               CyBle_ProcessEvents();

                     

                     

                    And the Client side:

                     

                    1)         case CYBLE_EVT_GATTC_HANDLE_VALUE_NTF:

                     

                                CYBLE_GATTC_HANDLE_VALUE_NTF_PARAM_T *RECEIVE_RX_data = (CYBLE_GATTC_HANDLE_VALUE_NTF_PARAM_T *)eventparam;

                                 receiveDataPacket[0]=(uint8)(*RECEIVE_RX_data->handleValPair.value.val);

                                 receiveDataPacket[1]=(uint8)((*RECEIVE_RX_data->handleValPair.value.val)>>8u);

                                 receiveDataPacket[2]=(uint8)((*RECEIVE_RX_data->handleValPair.value.val)>>16u);

                     

                                 break;

                     

                    Thanks!

                    • 7. Re: BLE data packet
                      user_78878863

                      You set the data length for the notification to '1', so only 1 byte will be transferred. Use

                      sendTxDataNtf.value.len  = 1;

                      • 8. Re: BLE data packet
                        wangbei325_2776061

                        I've tried sendTxDataNtf.value.len = 3; but it doesn't work.

                         

                        I send the code, because i am new in programming with Cypress BLE !, so could you please check them?

                         

                        Thank you!

                         

                        Server: app_Buttons.c

                        ------------------------------------------------------------------------------------------------------------

                        /*******************************************************************************

                        * File Name: app_Buttons.c

                        *******************************************************************************/

                        #include "main.h"

                        #include "stdio.h"

                        #include "app_Buttons.h"

                         

                        uint8 SendButtons8()

                        {

                            uint8 ButtonsState=0b00000000;

                           

                            if(Pin_S1_Read())

                            {

                                ButtonsState =0b00000001;

                            }else if(Pin_S2_Read())

                            {

                                ButtonsState =0b00000010;

                            }

                           

                            return ButtonsState;

                        }

                         

                        /* [] END OF FILE */

                         

                         

                        Server: app_accel.c

                        ------------------------------------------------------------------------------------------------------------

                        /*****************************************************************************************

                        * File Name: app_accel.c

                        *****************************************************************************************/

                        #include "app_accel.h"

                        #include "app_Ble.h"

                         

                        void SendCommand()

                        {

                          

                            CYBLE_GATTS_HANDLE_VALUE_NTF_T      sendTxDataNtf;

                           

                            if(Scan_Accelerometer())

                            {

                                  if(connStatus== CONNECTED)

                                  {       

                                           sendTxDataNtf.value.val  = sendDataPacket;

                                           sendTxDataNtf.value.len  = 3;

                                           sendTxDataNtf.attrHandle = CYBLE_SERVER_ACCEL_SERVER_ACCEL_TX_DATA_CHAR_HANDLE;

                                           CyBle_GattsNotification(cyBle_connHandle, &sendTxDataNtf); 

                                           CyBle_ProcessEvents();     

                                   }

                           }else

                          {

                              CySysPmSleep();

                           }

                        }

                         

                        uint8 Scan_Accelerometer()

                               if(Sensor_ADC_IsEndConversion(Sensor_ADC_RETURN_STATUS))

                               {

                                     int16 x= Sensor_ADC_CountsTo_mVolts(0, Sensor_ADC_GetResult16(0)) ;

                                     uint16 y=(uint16)x;

                                     //state=NORMAL;

                         

                                     uint8 buttons_temp = SendButtons8(); //z.B.0b00000010

                               

                                    sendDataPacket[0]= (uint8)y;

                                    sendDataPacket[1]= (uint8)(y >> 8u);      

                                    sendDataPacket[2]= (uint8)buttons_temp ;

                               

                                   return 1;

                         

                            }else{

                                   return 0;  

                            }

                        }

                        /* [] END OF FILE */

                         

                        Server: app_Ble.c

                        ------------------------------------------------------------------------------------------------------------

                        /*******************************************************************************

                        * File Name: app_Ble.c

                        *******************************************************************************/

                        #include "app_Ble.h"

                         

                        uint16 mtuSize      = CYBLE_GATT_MTU;  

                        extern uint8 applicationPower;

                         

                        void HandleBleProcessing(void)

                        {   

                              switch (cyBle_state)

                             {

                                    case CYBLE_STATE_ADVERTISING:

                                            break;

                               

                                   case CYBLE_STATE_CONNECTED:

                                            connStatus= CONNECTED;

                                            Sensor_ADC_Start();

                                            Sensor_ADC_StartConvert();         

                                            if(CyBle_GattGetBusStatus() != CYBLE_STACK_STATE_BUSY)

                                            {

                                                 SendCommand();

                                                 applicationPower = DEEPSLEEP;

                                            }

                                            break;      

                              

                                case CYBLE_STATE_DISCONNECTED:

                                        CyBle_GappStartAdvertisement(CYBLE_ADVERTISING_FAST);

                                        break;

                                default:

                                        break;      

                            }

                        }

                         

                         

                        void AppCallBack(uint32 event, void *eventParam)

                        {  

                            switch (event)

                            {

                                case CYBLE_EVT_STACK_ON:

                                        break;

                                   

                                case CYBLE_EVT_GAP_DEVICE_DISCONNECTED:

                                         RED_LED_ON();

                                         CyDelay(1000);

                                         break;

                                   

                                case CYBLE_EVT_GATT_CONNECT_IND:

                                        GREEN_LED_ON();

                                        break;

                                             

                                case CYBLE_EVT_GATTS_XCNHG_MTU_REQ:          

                                    if(CYBLE_GATT_MTU > ((CYBLE_GATT_XCHG_MTU_PARAM_T *)eventParam)->mtu)

                                    {

                                        mtuSize = ((CYBLE_GATT_XCHG_MTU_PARAM_T *)eventParam)->mtu;

                                    }else

                                    {

                                        mtuSize = CYBLE_GATT_MTU;

                                    }          

                                    break;

                                default:

                                    break;

                            }

                        }

                        /* [] END OF FILE */

                         

                         

                         

                         

                        Client: BLE_CAR_Client.c

                        ------------------------------------------------------------------------------------------------------------

                        /*******************************************************************************

                        * File Name: BLE_CAR_Client.c

                        *******************************************************************************/

                        #include "BLE_CAR_Client.h"

                        #include "LED.h"

                         

                        CYBLE_CONN_HANDLE_T connHandle;

                        CYBLE_API_RESULT_T apiResult;

                        CYBLE_GAP_BD_ADDR_T connectPeriphDevice;

                         

                        void FilterScanResponsePackets(CYBLE_GAPC_ADV_REPORT_T* scanReport)

                        {

                              if(scanReport->data[1] == MANUFACTURER_SPECIFIC_DATA &&

                                  scanReport->data[2] == COMPANY_LSB &&

                                 scanReport->data[3] == COMPANY_MSB &&

                                 scanReport->data[4] == MAN_SPEC_DATA_LSB && scanReport->data[5] == MAN_SPEC_DATA_MSB)

                              {

                                    CyBle_GapcStopScan();

                                    memcpy(connectPeriphDevice.bdAddr, scanReport->peerBdAddr,

                                       sizeof(connectPeriphDevice.bdAddr));

                                    ble_TRY_Server_found = TRUE;  

                              }

                        }

                         

                        void ApplicationEventHandler(uint32 event, void *eventparam)

                        {

                               switch(event)

                               {

                                     case CYBLE_EVT_STACK_ON:       

                                              break;

                         

                                    case CYBLE_EVT_GAPC_SCAN_START_STOP:

                                             break;

                         

                                   case CYBLE_EVT_GAPC_SCAN_PROGRESS_RESULT:

                                            FilterScanResponsePackets((CYBLE_GAPC_ADV_REPORT_T *)eventparam);

                                            break;

                         

                                  case CYBLE_EVT_GATT_CONNECT_IND:

                                          connHandle = *(CYBLE_CONN_HANDLE_T *)eventparam;

                                          break;

                         

                                 case CYBLE_EVT_GATT_DISCONNECT_IND:

                                          RED_LED_ON();

                                          CyDelay(1000);

                                          break;

                         

                                 case CYBLE_EVT_GAP_DEVICE_DISCONNECTED:

                                         RED_LED_ON();

                                         break;

                         

                                case CYBLE_EVT_GATTC_HANDLE_VALUE_NTF:

                                {

                                       CYBLE_GATTC_HANDLE_VALUE_NTF_PARAM_T *UART_RX_data = (CYBLE_GATTC_HANDLE_VALUE_NTF_PARAM_T *)eventparam;

                                       receiveDataPacket[0]=(uint8)(*UART_RX_data->handleValPair.value.val); 

                                       receiveDataPacket[1]=(uint8)((*UART_RX_data->handleValPair.value.val)>>8u);

                                       receiveDataPacket[2]=(uint8)((*UART_RX_data->handleValPair.value.val)>>16u);

                                     break;

                                 }

                         

                               default:

                                    break;

                               }

                        }

                        • 9. Re: BLE data packet
                          user_78878863

                          When you want to have someone looking at your project, please send the complete project ("File / Create Workspace Bundle"). This includes all files, and makes work easier.

                          For your problem: look at the actual definition of CyBle_GattsNotification and its parameter types. You will find that sendTxDataNtf.value.val is a pointer to the actual data (see type  CYBLE_GATT_VALUE_T), but you are trying to set its value directly. Use

                          sendTxDataNtf.value.val=&sendDataPacket;

                          instead.

                          • 10. Re: BLE data packet
                            wangbei325_2776061

                            Thank you first!

                             

                            Because i 've defined: uint8 sendDataPacket[3];

                             

                                                 so i indicate the pointer as :   sendTxDataNtf.value.val  = &sendDataPacket[0];

                             

                            I also send the entire packet of my project.

                             

                            Thanks in advance!