How to switch between connection handles when nrf52 is connected to multiple centrals?

[Pranay]

Hi,

I am using nRF52 and SDK13 with SoftDevice 132 v 4.0.2 which is now supporting multi-peripheral connections. I am using multi-peripheral example for reference. In that i have connected 4 android devices to nRF52. I want to send data from nRF52 to each of connected device. So i think I need to switch between connection handles to send data..How to achieve this?

[sijohans]

I also have some question about this. Assume my application can handle 4 concurrent connections and i configure the softdevice for this. Will the connection handles always be in range [0:3]?

If i have a structure (this is just an example) that holds the state of a client, and have an array of these structures, is it safe to use the connection handle as index in the array?

typedef struct ble_client_s {
    volatile uint8_t     is_connected;
    volatile uint8_t     notification_enabled;
    app_fifo_t  rx_queue;
    app_fifo_t  tx_queue;
    void        *p_context;
} ble_client_t;

static ble_client_t m_ble_clients[4];

static void isr_ble_evt_handler(ble_evt_t *p_ble_evt)
{
    switch (p_ble_evt->header.evt_id)
    {
        case BLE_GAP_EVT_CONNECTED:
        {
            m_ble_clients[p_ble_evt->evt.gatts_evt.conn_handle].is_connected = 1;
        } break; /* BLE_GAP_EVT_CONNECTED */
        case BLE_GAP_EVT_DISCONNECTED:
        {
            m_ble_clients[p_ble_evt->evt.gatts_evt.conn_handle].is_connected = 0;
        } break; /* BLE_GAP_EVT_DISCONNECTED */

        /* ... */

        default:
            break;

    }
}

If this a suitable solution to hold states of the different connected clients? Or can the connection handles have other values?

[RK]

no it's not - there's no guarantees abut the connection handle value. It might work today, it might fail dismally tomorrow with a new release. For full code compatibility you need to map them.

[sijohans]

Do you have a good suggestion for how to map them?

[FormerMember]

To map the various connection handles, you can for example use an array.