Unable to perform IQ sampling normally

[honghuahh]

SW version :2.4.0
HW revision: nRF52833 development board, PCA20054 Direction Finding Antenna Board 1_0_0
I use the routine director_finding_central  and  director_finding_periopheral for IQ sampling, and can obtain IQ sampling data.
When I put the original
static const uint8_t ant_patterns[] = { 0x2, 0x0, 0x5, 0x6, 0x1, 0x4,
0xC, 0x9, 0xE, 0xD, 0x8, 0xA };
Change to
static const uint8_t ant_patterns[] = { 0xC, 0x9, 0xE, 0xD, 0x8, 0xA,
0x2, 0x0, 0x5, 0x6, 0x1, 0x4 };
The Bluetooth connection will disconnect, making it impossible to perform normal IQ sampling.
May I ask why this situation has occurred?

Below is the serial port output

[Simonr]

Hi again

I've not heard back from the devs yet, and the expert on this is away until August 19th I'm afraid, so I'll try getting hold of him then and fill you in again then unless someone else chimes in before then.

Best regards,

Simon

[honghuahh]

OK，thanks. We found that there is noise when switching the antennas, but we are not sure if this is the main reason.

[Simonr]

Hi

I had a chat with the developer in charge of direction finding today, and they are not aware of any issues with the changing the antenna switching pattern. We ran a quick test today, using the configuration you mention, and did not see any issues with static const uint8_t ant_patterns[] = { 0xC, 0x9, 0xE, 0xD, 0x8, 0xA, 0x2, 0x0, 0x5, 0x6, 0x1, 0x4 }; 

Note that the order of the entries in the device tree should not be changed when using the Nordic antenna matrix. (The enable-gpio-patterns sequence that is). If the GPIOs are set up differently the radio will apply antenna-enable-patterns, but other antennas on the matrix are selected. So if you always also change the dfegpio0-gpios, you should only change the ant_patterns, as that works out of the box on our end.

The only other possibility we see is that there is too much noise in your testing environment that the two devices aren't able to connect, but then again it would be strange that it works with the default antenna pattern.

Best regards,

Simon

[honghuahh]

OK，thanks. Maybe there is too much noise. Recently, we did another test. The postion that couldn't be received before can now be received again. We ' ll do some more tests later.