About CONN_PARAMS_UPDATE_DELAY....

[J.Park]

#define FIRST_CONN_PARAMS_UPDATE_DELAY APP_TIMER_TICKS(20000) //20s

/**< Time from initiating event (connect or start of notification) to first time sd_ble_gap_conn_param_update is called (15 seconds). */

#define NEXT_CONN_PARAMS_UPDATE_DELAY APP_TIMER_TICKS(5000) //5s

/**< Time between each call to sd_ble_gap_conn_param_update after the first call (5 seconds). */

#define MAX_CONN_PARAMS_UPDATE_COUNT 3 /**< Number of attempts before giving up the connection parameter negotiation. */

What exactly does the above variables do???

[Einar Thorsrud]

Hi,

These defines are used in many SDK examples, and all are used to populate an instance of ble_conn_params_init_t that is passed to the connection parameters module by a call to ble_conn_params_init(). The FIRST_CONN_PARAMS_UPDATE_DELAY is used to configure a delay between when the connection is established and the first connection parameter update request. NEXT_CONN_PARAMS_UPDATE_DELAY configures the delay between requests, and MAX_CONN_PARAMS_UPDATE_COUNT configures the maximum amount of attempts (requests) before giving up. In this case, the module will optionally disconnect, if disconnect_on_fail was set to true.

You can refer to the API documentation for ble_conn_params_init_t struct and the documentation for the connection parameter module for more details.