CTEInfo receive with antenna switch

[loquat]

I am developing AoA for nRF52833.

Please tell me about antenna switching.

Setting:

PSEL.DFEGPIO[0]=28
PSEL.DFEGPIO[1]=29
PSEL.DFEGPIO[2]=30
PSEL.DFEGPIO[3]=31

SWITCHPATTERN=0x0
SWITCHPATTERN=0x0
SWITCHPATTERN=0x1
SWITCHPATTERN=0x2
SWITCHPATTERN=0x4
SWITCHPATTERN=0x8

GPIO.DIRSET=0xF0000000
GPIO.OUT=0x00000000

Use CTE inline mode.

If Advertising with CTEInfo is received, the antenna switch will work as expected.

If Advertising without CTEInfo is received, PORT28/29 will change immediately after receiving the Advertising. (It outputs a pulse)

(There will be no change if no Advertising is received at all)

Is this normal operation?

[Priyanka]

Hi,

It looks fine, because as you mentioned,

If Advertising with CTEInfo is received, the antenna switch will work as expected.

This is correct.

If Advertising without CTEInfo is received, PORT28/29 will change immediately after receiving the Advertising. (It outputs a pulse)

The pulse that you see initially might be the radio getting ready for the CTE reception, but since the CTEInfo is not received, the antenna switching is not performed.

(There will be no change if no Advertising is received at all)

That also looks fine.

Regards,

Priyanka

[loquat]

Thanks.

I changed the settings a little.

PSEL.DFEGPIO[0]=28
PSEL.DFEGPIO[1]=29
PSEL.DFEGPIO[2]=30
PSEL.DFEGPIO[3]=31

SWITCHPATTERN=0x00 (Scan and Payload)
SWITCHPATTERN=0x01 (reference period)
SWITCHPATTERN=0x02 (1st sample period)
SWITCHPATTERN=0x04 (2nd sample period)
SWITCHPATTERN=0x08 (3rd sample period)

GPIO.DIRSET=0xF0000000
GPIO.OUT=0x00000000

result is follow,

On recv no-CTEInfo (INLINE AoA mode)
'reference period' and 'sample period' will be output, but this is unnecessary processing.
Additionally there is an unnecessary delay between END_EVENT and PHYEND_EVENT.

Is this behavior as expected?

[Priyanka]

Could you tell me whether you made this block/timing diagram yourself?

Could you tell me what you mean by "receiving no CTE info"?

Regards,

Priyanka

[loquat]

The timing is output to GPIO using PPI.
END_EVENT -> PPI -> GPIO0
PHYEND_EVENT ->PPI -> GPIO1
etc.

About CTEInfo
The sender uses Timeslot API to add CTEInfo to the ExtendedHeader of the ADV_EXT_IND packet, and also sets it to send CTE after CRC.
The receiver uses Timeslot API to receive in inlineAoA mode.

[Priyanka]

Hi,

Apologies for the delay. I am checking this internally with experts and will get back to you.

-Priyanka

[Priyanka]

loquat said:

'reference period' and 'sample period' will be output, but this is unnecessary processing.

If you are referring to this "part of the protocol" then it definitely isn't unnecessary - it's important in order to find the bias etc.

loquat said:

Additionally there is an unnecessary delay between END_EVENT and PHYEND_EVENT.

If you are seeing delays etc. that is interesting, but you will have to give us more details than that. You should measure this with a logic analyzer or PPK and give us what values for sample slot etc. you are using, or if you're simply using the default values. And whether you are using zephyr controller, and what ncs version. And you should definitely try this with NCS 2.2, as that is the only version we've tested and know that we have a QDID. Most likely you would just need to look at the WP.

-Priyanka