how to send characteristic value to another nrf51DK board

RE: how to send characteristic value to another nrf51DK board

endnode — Tue, 22 Aug 2017 13:26:07 GMT

No my friend I cannot. However if you are using nRF5_SDK_14.0.0_3bcc1f7\examples\ble_central\ble_app_uart_c project then you can see at line #296 of main.c file following construction and that's where Event Notification data should appear if send from Nordic UART Server by HVX method:

case BLE_NUS_C_EVT_NUS_TX_EVT:
    ble_nus_chars_received_uart_print(p_ble_nus_evt->p_data, p_ble_nus_evt->data_len);
    break;

Either is your GAP Peripheral/GATT Server piece compatible with it immediately or you need to dig deeper into ble_nus_c module how it actually processes HVX events.

RE: how to send characteristic value to another nrf51DK board

norin saiyed — Tue, 22 Aug 2017 13:09:42 GMT

can you please send some reference code???

RE: how to send characteristic value to another nrf51DK board

endnode — Tue, 22 Aug 2017 12:49:27 GMT

You don't read it, you will receive it as asynchronous event. If you use event handler directly on top of Soft Device then you will see BLE_GATTC_EVT_HVX coming (note that this can change depending on Soft Device version you use so consult proper API spec). Then in event data structure you can see what arrived. However if you use some modules to manage certain SoftDevice events then this might be hidden from you in their callback functions or some internal state machines...

RE: how to send characteristic value to another nrf51DK board

norin saiyed — Tue, 22 Aug 2017 12:37:26 GMT

how do i read notification string send by a peripheral device with ble_app_uart_c example..I have configured proper uuid for both peripheral and central

RE: how to send characteristic value to another nrf51DK board

endnode — Tue, 22 Aug 2017 12:21:23 GMT

You will firstly need to have matching "profiles" meaning good opposite GAP and GATT roles and on GATT layer Server must expose right Service(s) and Characteristic(s) with the right UUID and on Client side your app must be looking for the same. Finally on top of these GATT objects you need to define "protocol" (it can be as simple as "pass the data stream over without any structure so just raw byte stream") and implement on both sides. Only then devices will work together. But this is like for any other machine in this universe, right? If you want to talk to it, you need to use correct language...

RE: how to send characteristic value to another nrf51DK board

norin saiyed — Tue, 22 Aug 2017 12:08:13 GMT

Hi, I have tried ble_app_uart_c example as a central device.. but not able to get the response. How should i get the values send by a peripheral device on my central device???

RE: how to send characteristic value to another nrf51DK board

endnode — Tue, 22 Aug 2017 11:48:01 GMT

Then one of the boards must be Master (GAP Central) and second Slave (GAP Peripheral) In your case of LightBlu is your iPhone most probably Master so you need to achieve the same behavior in nRF5x FW to see the same. Have you ever run some nRF5 SDK examples against each other like Nordic BLE UART Service (NUS)? There are both Peripheral (+ GATT Server) and Central (+ GATT Client) examples in the SDK so I would start with them...