S130_1.0.0 - Unstable scan

[Yaroslav]

Hi. My app based on S130_1.0.0 and is run on DevKit with 51422 chip. App advertises and scans at the same time with next params:

• adv interval = 20mS;

• scan interval = 200mS;

• scan window = 100mS;

• scanner is started before advertiser in main();

This all is run on two DK boards so each nRF receives adv packets of the other. During testing app I have noticed that after some time (several minutes) both nRF receives less and less adv packets during ~1 min until stop receiving advs at all for ~1 min and then again receives more and more adv packets till receiving almost all adv. Such behavior looks like some wave of receiving adv. Using MCP on my PC I have verified than both nRF advertise all this time, so seems problem is with scanner.

Could you explain such behavior? Is it expected or it's unknown bug in SD? Can you advice anything to avoid losing adv packets during so long time? Thanks!

[Yaroslav]

recently I tried to change scan window and interval and got some results:

1) scan window = 0x0090;
    scan interval = 0x00A0;  
    And scanner received adv packets very rarely - with big gaps;

2) scan window = 0x0010;
    scan interval = 0x0020;
    And scanner received much better - maximum gap between adv packets about 2 sec and the most of adv packets were received in time;

I think this investigation can help you. I assume that SD has problems with scheduler.