How to enable BLE 2MBPS

[vn2000]

Hello,

I'm trying to enable 2MBPS using 2 nRF52840-DK. I'm using SDK17 examples with Segger Embedded Studio. The peripheral uses the ble_app_uart example. The central uses ble_app_uart_c example.

I was able to make them work as default at 1MBPS, but I have problems making them work at 2MBPS. I saw a similar issue at another post but that didn't help me to resolve my issue.

I did the following changes on the central 2MBPS, in ble_evt_handler:

case BLE_GAP_EVT_PHY_UPDATE_REQUEST:
{
    printf("PHY update request.");
    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);
} break;

In the peripheral, I made these changes:

static void ble_evt_handler(ble_evt_t const * p_ble_evt, void * p_context)
{
    uint32_t err_code;

    ble_gap_phys_t m_test_params;
    m_test_params.tx_phys = BLE_GAP_PHY_2MBPS;
    m_test_params.rx_phys = BLE_GAP_PHY_2MBPS;

    switch (p_ble_evt->header.evt_id)
    {
        case BLE_GAP_EVT_CONNECTED:
            printf("Connected\r\n");
            err_code = bsp_indication_set(BSP_INDICATE_CONNECTED);
            APP_ERROR_CHECK(err_code);
            m_conn_handle = p_ble_evt->evt.gap_evt.conn_handle;
            err_code = nrf_ble_qwr_conn_handle_assign(&m_qwr, m_conn_handle);
            APP_ERROR_CHECK(err_code);
            // Add these lines for 2MBPS
            err_code = sd_ble_gap_phy_update(m_conn_handle, &m_test_params);
            APP_ERROR_CHECK(err_code);
            break;

        case BLE_GAP_EVT_PHY_UPDATE:
            printf("BLE_GAP_EVT_PHY_UPDATE\r\n");
           break;

..........

}

After the changes, they still operate at 1MBPS. Even though I see the printout BLE_GAP_EVT_PHY_UPDATE on the peripheral, as well a message .'PHY update request' on the central device, showing they are supposed to update the PHY to 2MBPS.

I wonder what else needs to be done. I appreciate any help to resolve the issue.

[Hieu]

Hi vn2000,

Could you go deeper into the event structure and get the details of BLE_GAP_EVT_PHY_UPDATE?

You can get from the fields of p_ble_evt->gap.evt.phy_update.

Reference: infocenter.nordicsemi.com/.../structble__gap__evt__phy__update__t.html

Hieu

[vn2000]

Hi Hieu,

I made the following changes in BLE_GAP_EVT_PHY_UPDATE.

ble_gap_evt_t const * const p_gap = &p_ble_evt->evt.gap_evt;

case BLE_GAP_EVT_PHY_UPDATE:
    printf("Received BLE_GAP_EVT_PHY_UPDATE (RX:%d, TX:%d, status:%d)",
            p_gap->params.phy_update.rx_phy,
            p_gap->params.phy_update.tx_phy,
            p_gap->params.phy_update.status);
    break;

I see the output:
Received BLE_GAP_EVT_PHY_UPDATE (RX:2, TX:2, status:0).

So it looks like the RX and TX PHY are changed to 2MBPS. But why don't I get a speed change? Could it be my test program didn't work correctly. Do you recommend any test program that tests the 2MBPS throughput?

Thanks.

[Hieu]

Hi vn2000,

An even better way to confirm whether you have 2M PHY is to get a sniffer trace. You can use the nRF Sniffer for that.

The Throughput Example is created for throughput testing purpose. Would you like to give that a try?
Here is its documentation: https://infocenter.nordicsemi.com/topic/sdk_nrf5_v17.1.0/ble_sdk_app_att_mtu.html.

Hieu

[vn2000]

Hi Hieu,

I want to make sure I'm using the right example you suggested. I'm using SDK V17;

\nRF5_SDK\V17\examples\ble_central_and_peripheral\experimental\ble_app_att_mtu_throughput

So I will use this same example on both central and peripheral device?

[Hieu]

Hi vn2000,

Yes, the path to the example and a step-by-step guide to perform the test are all include in the link in my previous answer

[vn2000]

Hi Hieu,

I was tied up by another task last couple days. Now I compiled and downloaded both boards and I encountered some problems.

On the tester board, I pushed the button 3 and I see this:

throughput example:~$ config print
==== Current test configuration ====
Board role: tester
ATT MTU size: 247
Data length: 27
Connection interval: 6 units
Connection length ext: on
Preferred PHY: 2 Mbps
GAP event length: 400

On the dummy board, I pushed the button 4 and I see this:

throughput example:~$ config print
==== Current test configuration ====
Board role: dummy
ATT MTU size: 247
Data length: 251
Connection interval: 6 units
Connection length ext: on
Preferred PHY: 2 Mbps
GAP event length: 400

The Data length are different. Do they need to be equal?

When I type 'run', the dummy board complained:

'Wrong board setup!'

Do you have any suggestion?

[Hieu]

Welcome back vn2000,

The Data Length doesn't seem to have to be equal.
I reviewed the source code and see that the example would complain "Wrong board setup!" if you call run from the dummy/responder board.
Please command "run" on the tester board. 

Here is my log for your reference.

[vn2000]

Hello Hieu,

I can make it work now. The only thing I have to set the data length to 251 on the tester. I don't know why it was not set to 251 as default like the dummy board. I can fix it in the firmware.

Anyway thank you for your help. Nordic is the best.