5 Replies Latest reply on Sep 19, 2017 11:00 AM by epr_1639216

    Advertising Event duration on CY8C4248LQI-BL483 dependent on scan response



      I performed current consumption measurements on the CY8CKIT-042-BLE Pioneer Kit. The measurements were mostly focused on the advertising of BLE, advertising on all three possible channels. While performing the current measurements I made a strange observation where I have no explanation for. Maybe someone here can help me:


      Leaving the bytes of data under "Advertisement packet" constant and changing the "Scan response packet" data (so different number of bytes) showed a huge difference in current and therefore in power consumption. First I thought this would be because of another BLE device which is scanning. But this was not the case. There were no scan responses observable. Taking a closer look to the advertising event showed that there was a difference in the duration of the Inter-Channel-Delay. So, e.g., when choosing a scan response packet of 31 Bytes, the Inter-Channel-Delay took longer as when choosing a scan response packet of 3 Bytes. Nevertheless, the scan response was NEVER sent. According to AN92584 [1], page 37 the Inter-Channel-Delay should be fixed at 1.25ms, which is in my case definitely not true. Nevertheless, according to the Bluetooth Standard 4.2 this Inter-Channel-Delay has to be shorter than 10ms, therefore of course the functionality is not restricted.


      Could someone explain to me why the Inter-Channel-Delay is variable? What is the reason behind it?


      Best regards and many thanks in advance,


      [1] http://www.cypress.com/file/140991/download