if i disconnect slave a, slave b will auto disconnect also, and later slave b connect again.

[lyman]

dear 

i am using this project as slave

\nRF5_SDK_14.2.0_17b948a\examples\ble_peripheral\ble_app_uart\

this project as central

\nRF5_SDK_14.2.0_17b948a\examples\ble_central\ble_app_uart_c\

i have two slave connected with the center.

i find a problem,

if i disconnect slave a, slave b will auto disconnect also, and later slave b connect again.

i doubt this maybe the softdevice's scheme ?

why is it designed like this ?

i think although slave a is disconnected, slave b should not be affected .....

[Hung Bui]

Hi Lyman, 

As far as I know the ble_app_uart_c only connect to one board at a time. Did you modify the code to connect to multiple server ? 

Have you made sure you used the correct conn_handle when dealing with multiple servers/slaves ? 

How did you disconnect slave a ? 

[lyman]

i define  more instance 

BLE_NUS_C_DEF(m_ble_nus_c); /**< BLE NUS service client instance. */
BLE_NUS_C_DEF(m_ble_nus_c1);
BLE_NUS_C_DEF(m_ble_nus_c2);
BLE_NUS_C_DEF(m_ble_nus_c3);

BLE_DB_DISCOVERY_DEF(m_db_disc);
BLE_DB_DISCOVERY_DEF(m_db_disc1);
BLE_DB_DISCOVERY_DEF(m_db_disc2);
BLE_DB_DISCOVERY_DEF(m_db_disc3);

in function static void ble_evt_handler(ble_evt_t const * p_ble_evt, void * p_context)

i add the following code 

if(p_ble_evt->evt.gap_evt.conn_handle == 0)
{
err_code = ble_nus_c_handles_assign(&m_ble_nus_c, p_ble_evt->evt.gap_evt.conn_handle, NULL);
APP_ERROR_CHECK(err_code);
}
if(p_ble_evt->evt.gap_evt.conn_handle == 1)
{
err_code = ble_nus_c_handles_assign(&m_ble_nus_c1, p_ble_evt->evt.gap_evt.conn_handle, NULL);
APP_ERROR_CHECK(err_code);
}
if(p_ble_evt->evt.gap_evt.conn_handle == 2)
{
err_code = ble_nus_c_handles_assign(&m_ble_nus_c2, p_ble_evt->evt.gap_evt.conn_handle, NULL);
APP_ERROR_CHECK(err_code);
}
if(p_ble_evt->evt.gap_evt.conn_handle == 3)
{
err_code = ble_nus_c_handles_assign(&m_ble_nus_c3, p_ble_evt->evt.gap_evt.conn_handle, NULL);
APP_ERROR_CHECK(err_code);
}

if(p_ble_evt->evt.gap_evt.conn_handle == 0)
{
err_code = ble_db_discovery_start(&m_db_disc, p_ble_evt->evt.gap_evt.conn_handle);
APP_ERROR_CHECK(err_code);
}
if(p_ble_evt->evt.gap_evt.conn_handle == 1)
{
err_code = ble_db_discovery_start(&m_db_disc1, p_ble_evt->evt.gap_evt.conn_handle);
APP_ERROR_CHECK(err_code);
}

if(p_ble_evt->evt.gap_evt.conn_handle == 2)
{
err_code = ble_db_discovery_start(&m_db_disc2, p_ble_evt->evt.gap_evt.conn_handle);
APP_ERROR_CHECK(err_code);
}
if(p_ble_evt->evt.gap_evt.conn_handle == 3)
{
err_code = ble_db_discovery_start(&m_db_disc3, p_ble_evt->evt.gap_evt.conn_handle);
APP_ERROR_CHECK(err_code);
}
err_code = bsp_indication_set(BSP_INDICATE_CONNECTED);
APP_ERROR_CHECK(err_code);

if (ble_conn_state_n_centrals() == NRF_SDH_BLE_CENTRAL_LINK_COUNT)
{
;
}
else
{
scan_start();
}

the config's following 

// <o> NRF_SDH_BLE_PERIPHERAL_LINK_COUNT - Maximum number of peripheral links.
#ifndef NRF_SDH_BLE_PERIPHERAL_LINK_COUNT
#define NRF_SDH_BLE_PERIPHERAL_LINK_COUNT 0
#endif

// <o> NRF_SDH_BLE_CENTRAL_LINK_COUNT - Maximum number of central links.
#ifndef NRF_SDH_BLE_CENTRAL_LINK_COUNT
#define NRF_SDH_BLE_CENTRAL_LINK_COUNT 4
#endif

// <o> NRF_SDH_BLE_TOTAL_LINK_COUNT - Maximum number of total concurrent connections using the default configuration.
#ifndef NRF_SDH_BLE_TOTAL_LINK_COUNT
#define NRF_SDH_BLE_TOTAL_LINK_COUNT 4
#endif

// <o> NRF_SDH_BLE_GAP_EVENT_LENGTH - The time set aside for this connection on every connection interval in 1.25 ms units.
#ifndef NRF_SDH_BLE_GAP_EVENT_LENGTH
#define NRF_SDH_BLE_GAP_EVENT_LENGTH 3
#endif

// <o> NRF_SDH_BLE_GATT_MAX_MTU_SIZE - Static maximum MTU size.
#ifndef NRF_SDH_BLE_GATT_MAX_MTU_SIZE
#define NRF_SDH_BLE_GATT_MAX_MTU_SIZE 247
#endif

// <o> NRF_SDH_BLE_GATTS_ATTR_TAB_SIZE - Attribute Table size in bytes. The size must be a multiple of 4.
#ifndef NRF_SDH_BLE_GATTS_ATTR_TAB_SIZE
#define NRF_SDH_BLE_GATTS_ATTR_TAB_SIZE 1408
#endif

// <o> NRF_SDH_BLE_VS_UUID_COUNT - The number of vendor-specific UUIDs.
#ifndef NRF_SDH_BLE_VS_UUID_COUNT
#define NRF_SDH_BLE_VS_UUID_COUNT 1
#endif

// <q> NRF_SDH_BLE_SERVICE_CHANGED - Include the Service Changed characteristic in the Attribute Table.

#ifndef NRF_SDH_BLE_SERVICE_CHANGED
#define NRF_SDH_BLE_SERVICE_CHANGED 0
#endif

[Hung Bui]

Please answer the question regarding on how you disconnect the slave ? 
Please post the code where you handle BLE_GAP_EVT_DISCONNECTED.

I assume you have 4 different m_conn_handle ? 

On slave B, which disconnect reason do you get ? 

A sniffer trace on slave B connection could be useful to see why it get disconnected.