BT 5.0 on "ble_app_uart"

[Bar1]

Hi All,

I used the app "ble_app_uart"  and "ble_app_uart_c" on two custom boards mounting a n52840 QIAACO.

I know that in the app (nRF5_SDK_15.1.0_a8c0c4d\examples\ble_peripheral\ble_app_uart) is not used the BT 5.0 2phy but the 1phy.

My question is: what should I change to have a faster data transfer using the 2phy instead of 1phy from the peripheral to the central unit?

I tried just to replace BLE_GAP_PHY_1MBPS with BLE_GAP_PHY_2MBPS in the whole code but apparently it is not enough.

Thanks in advance,

[Stian Røed Hafskjold]

The peripheral/central needs to request a phy update and the central/peripheral needs to respond to it. Please check out the sequence diagrams:

http://infocenter.nordicsemi.com/topic/com.nordic.infocenter.s140.api.v6.1.0/group___b_l_e___g_a_p___c_e_n_t_r_a_l___p_h_y___u_p_d_a_t_e.html?cp=2_3_2_1_0_2_1_3_7_0

http://infocenter.nordicsemi.com/topic/com.nordic.infocenter.s140.api.v6.1.0/group___b_l_e___g_a_p___p_e_r_i_p_h_e_r_a_l___p_h_y___u_p_d_a_t_e.html?cp=2_3_2_1_0_2_1_3_7_1

Here the peripheral requests an update procedure. You can for example call this function in the ble_evt_handler under BLE_GAP_EVT_CONNECTED:

void phy_update_request(ble_evt_t const * p_ble_evt){
    ret_code_t err_code;
    ble_gap_phys_t const phys =
    {
        .rx_phys = BLE_GAP_PHY_2MBPS,
        .tx_phys = BLE_GAP_PHY_2MBPS,
    };
    err_code = sd_ble_gap_phy_update(p_ble_evt->evt.gap_evt.conn_handle, &phys);
    APP_ERROR_CHECK(err_code);
}

Central then responds in ble_evt_handler:

case BLE_GAP_EVT_PHY_UPDATE_REQUEST:
{
    NRF_LOG_DEBUG("PHY update request.");
    ble_gap_phys_t const phys =
    {
        .rx_phys = BLE_GAP_PHY_AUTO,
        .tx_phys = BLE_GAP_PHY_AUTO,
    };
    err_code = sd_ble_gap_phy_update(p_ble_evt->evt.gap_evt.conn_handle, &phys);
    APP_ERROR_CHECK(err_code);
} break;

[Bar1]

Hi Stian,

I did what you suggested but I did not get anything faster.

When I try to write something on the UART of ble_app_uart_peripheral, this message is sent to the ble_app_uart_c and also it is printed on the UART of ble_app_uart_peripheral which plays the role of echo.

Do you think that this can reduce the speed of the whole system? If yes what should I change in the code to do not have the "echo" on the ble_app_uart_peripheral.

Thanks in advance