sd_ble_gatts_hvx() return NRF_SUCCESS,but The data obtained by the app is wrong

[Ming]

hi,

The data is sent to the app by sd_ble_gatts_hvx(), but the data obtained by this app is wrong.

When salve sends a byte, the data obtained by the app is always 0,but the data I sent is not 0.And Event BLE_GATTS_EVT_HVN_TX_COMPLETE is also successfully triggered. 

Meanwhile,I checked the value of the handle, the value is 0x0000.And  If the value of "ble_gatts_hvx_params_t.p_len" is changed, the app can get incorrect data of different lengths.   

The documents were not found. If I want to use this function correctly, what needs to be noticed.

[Amanda Hsieh]

Hi Ming, 

Which SDK are you using?

Did you check the value of hvx_params.p_data? You can take a look at UART/Serial Port Emulation over BLE to see how ble_nus_data_send() -> sd_ble_gatts_hvx() work. 

-Amanda H.

[Ming]

Hi Amanda,

I used the sdk of 15.3.

And I checked the value of  hvx_params.p_data and This data was printed before sending, it is normal. 

I used this demo of app_uart, and it looks no different from my used.

[Ming]

Hi Amanda,

Thanks very much.I found it. I used the  BLE_GATTS_VLOC_STACK  when I added the characteristic.

-Ming