CTE packet recognition

[Siddharth Venkatesh]

Hi 

I am currently trying to append the CTE extension to a normal packet using the tx and rx examples from the SDK. The examples I am using are in examples/peripherals/radio. 

I have the code to append the CTE extension which is:

NRF_RADIO->DFEMODE = RADIO_DFEMODE_DFEOPMODE_AoA; 

NRF_RADIO->DFECTRL1 = 3 << RADIO_DFECTRL1_NUMBEROF8US_Pos | 1 << RADIO_DFECTRL1_DFEINEXTENSION_Pos;

But I can't see if I have appended the CTE extension or not. What would be an easy way to see the information I am sending through? 

Thanks

[Andreas]

Hi,

 

The easiest way would be to demodulate the signal, e.g. using a spectrum analyzer.

 

You could probably use a timer, or increment a variable in a while loop, to get the time between EVENTS_END and EVENTS_PHYEND. If they happen at the same time then there is no CTE, if the time between is similar to what you configure in DFECTRL1 then there is CTE.

 

Best regards,

Andreas

[Siddharth Venkatesh]

Hi 

Thanks for that. I did as you suggested and implemented a variable increment. The code for that is below. 

while (NRF_RADIO->EVENTS_PHYEND == 0U)
{
        while (NRF_RADIO->EVENTS_END == 0U)
        {
        }
        a++;
}

And the output did show that when I had the code from my original question working, the variable 'a' was higher. This confirmed that the having the CTE code increased the time before the EVENTS_PHYEND event happened. 

Without the CTE code, 'a' was 7.

With the CTE code, 'a' was 42.

However when I checked the value of:

NRF_RADIO->EVENTS_CTEPRESENT

to see if the CTE was present, the value kept displaying 0. I don't know why it is 0 even though I can see an increase the variable 'a'.

Am I using this EVENTS_CTEPRESENT variable wrong? Or is the CTE code I have shown in my original question not enough to generate a CTE packet?

Thanks

[Andreas]

Hi,

 

EVENTS_CTEPRESENT is only generated in RX, if I understand you correctly you are looking at TX for now. Even so it requires that you structure the CTEinfo packet contents correctly, as described in the PS.

 

I still think your method is sufficient to prove there is a CTE appended to your packet.

 

Best regards,

Andreas