ble_app_hrs_c --scan stopped

[Mike]

I programmed nRF51822 with S120 softdevice and ble_app_hrs_c application to scan beacons. It works fine but have one problem.

• It scans beacons for about 10 seconds then stop scanning for about 10 seconds and repeat scanning.

What makes this kind of symptoms scanning-stop-scanning-stop every 10 seconds period.

[Roger Clark]

Hi Mike

Ah. I thought it had completely stopped reporting the first beacon, and only the second beacon was being received.

But like Stefan says, if it starts receiving the first beacon again after a further 10 seconds, its a sort of time phasing issue which is happening

[Mike]

I tested Scan Interval and Scan Windows both set to 0x00A0 then it's much berrer. As my caculation, value 0x00A0 is 160*1000/0.625=256ms not 100ms. I'm wrong ? But still occationally missing scanning beacon, eg. 60times scan ok then one scan missing etc.

[Stefan Birnir Sverrisson]

I think 160*0.625=100ms. Beacons are advertising packets, which do not have acknowledgement. You might be occasionally missing packets, because of other BLE devices in the area, WIFI, or other devices transmitting in the 2.4GHz band. So losing every 60th packet might be normal when advertising.