Significant difference in connection time with different adv intervals

[nordicdev]

Hi,

I have the following set up:

The remote: nrf51822 acts as central

The wheels: Each wheel has nrf51822 acting as peripheral.

The remote needs to first connect(at time: T1), then bond with both the wheels, exchange some handshake information regarding wheel status with both wheels, then proceed to active mode at time: T2(where both wheels are controlled by the remote).Connection interval is : 7.5msec to 30msec.

Case 1: When both wheels have advertisement interval as: 50msec, T2-T1 is less than a second.

Case 2: When both wheels have advertisement interval as: 200msec, T2-T1 is approximately 3 seconds.

Why is the huge time difference (more than a second) in case 1 and 2? Is this an expected behaviour?

Thanks.

[nordicdev]

Hi run_ar, thanks for the reply. Please find my settings:

Hash define SCAN_INTERVAL 0x00A0 // Determines scan interval in units of 0.625 millisecond.

Hash define SCAN_WINDOW 0x0050 // Determines scan window in units of 0.625 millisecond.

Hash define SCAN_TIMEOUT 0x0000 // Timout when scanning. 0x0000 disables timeout.

Hash define MIN_CONNECTION_INTERVAL MSEC_TO_UNITS(7.5, UNIT_1_25_MS)

Hash define MAX_CONNECTION_INTERVAL MSEC_TO_UNITS(30, UNIT_1_25_MS)

I thought, from a logical point of view, there wouldnt be much of a difference (from a user point of view - seeing how long it takes to connect) when advertisement interval is 50msec Vs200msec. Please correct me if I am wrong.