Master skipping Connection Event

[Donal]

Hi There,

Under what condition(s) would a master skip a Connection Event (i.e. not transmit to the slave)? We are currently testing using v12.1 SDK. I have configured the Peripheral with the following connection interval settings:

#define MIN_CONN_INTERVAL               MSEC_TO_UNITS(50, UNIT_1_25_MS)
#define MAX_CONN_INTERVAL               MSEC_TO_UNITS(100, UNIT_1_25_MS)

The master will always set 75ms as the interval in the Connection request.

In our test, we are continuously sending a write request from the master, each time the master receives a response from the slave (on the BLE_GATTC_EVT_WRITE_RSP event we call sd_ble_gattc_write() with an appropriate write request payload).

What we see is that every 4th message sent by the master is delayed by 1 Connection Interval. Why would this be?

[Donal]

Closing this, as it looks like I had some configuration issue in my central application. I have rolled back all changes to a known good version and the delay is now not there.