Hi!
I am running Zephyr sample application for direction finding zephyr/samples/bluetooth/direction_finding_connectionless_rx with minor modifications on nRF52833 DK. I have set my ant_patterns to {5U, 3U, 5U, 3U} (only two antennae repeating till 160 us of CTE is reached). After I got some unexpected results I checked my output pins driven by radio on oscilloscope and saw something that I am not aware of from BT core spec.
I have configured switching and sampling slot to be 2 us. First results are shown on picture below. Every time switching happens purple signal should change its value (as well as cyan)
From what I have read from BT core spec than in my example every 4 us (2*slot_duration) switching should occur. But in my case switching occurs after 4 us than 8 us and again 4 us and 8 us (4 us, 8 us, 4 us , 8 us,...). It looks like I got delayed switching for 4 us every time purple signal is at high level. It looks like that every time antenna pattern is repeated switching got delayed.
If I changed my antenna pattern to {5U, 3U, 5U, 3U, 5U, 3U, 5U, 3U, 5U, 3U, 5U, 3U} (same as before but I added repeating pattern by hand) I got following results:
From this picture it is clear that the amount of repeating sequences I wrote to antenna pattern by hand than I get this number of switching correct. But then when all this pattern is repeated, next switching is again delayed for 4 us (8 us since last switch happened).
Is this some sort of bug in software or in hardware or am I missing something from BT core spec? Is this delay normal before every time switching pattern from ant_patterns is repeated?
Any help would be appreciated.
