This post is older than 2 years and might not be relevant anymore
More Info: Consider searching for newer posts

GPIO setup parameters for AoA Antenna switching

I have an issue with getting the I/Os correctly setup for antenna switching.

I am running the radio_test example code with the following modifications. 

So far, I have the following code for the GPIO setup:

//Defines are at top of file
#define ANT1 NRF_GPIO_PIN_MAP(0,17)
#define ANT2 NRF_GPIO_PIN_MAP(1,8)
#define ANT3 NRF_GPIO_PIN_MAP(1,7)
#define ANT4 NRF_GPIO_PIN_MAP(1,6)

//other support code

//Pin config
nrf_gpio_pin_clear(ANT1);
nrf_gpio_cfg_output(ANT1);
nrf_gpio_pin_clear(ANT2);
nrf_gpio_cfg_output(ANT2);
nrf_gpio_pin_clear(ANT3);
nrf_gpio_cfg_output(ANT3);
nrf_gpio_pin_clear(ANT4);
nrf_gpio_cfg_output(ANT4);

//DFE pin config
NRF_RADIO->PSEL.DFEGPIO[0] = ANT1; //(P0.17)
NRF_RADIO->PSEL.DFEGPIO[1] = ANT2; //(P1.08)
NRF_RADIO->PSEL.DFEGPIO[2] = ANT3; //(P1.07)
NRF_RADIO->PSEL.DFEGPIO[4] = ANT4; //(P1.06)

NRF_RADIO->SWITCHPATTERN = 1; //Only P0.07 active
NRF_RADIO->SWITCHPATTERN = 2; //Only P1.08 active
NRF_RADIO->SWITCHPATTERN = 4; //Only P1.07 active
NRF_RADIO->SWITCHPATTERN = 8; //Only P1.06 active

NRF_RADIO->DFEMODE = RADIO_DFEMODE_DFEOPMODE_AoA;
NRF_RADIO->DFECTRL1 = 10 << RADIO_DFECTRL1_NUMBEROF8US_Pos | 
                       1 << RADIO_DFECTRL1_DFEINEXTENSION_Pos;

Then in the radio_test.c file, I include in the function radio_rx( ...)

uint32_t g_iq_packet[RADIO_MAX_PAYLOAD_LEN];

void radio_rx(....)
{
//orig example code still exists here, only not shown
    NRF_RADIO->DFEPACKET.PTR = (uint32_t)g_iq_packet;

}

From a board running the radio_test example, I issue the 'start_tx_modulated_carrier' command the immediately issue the 'start_rx" command on a seperate DK also running the radio_test example with the above modifications.

I expected to see a short duration square wave on each of the antenna GPIO pins, so, 4 square waves cascading in time. However from my logic analyzer capture, you can clearly see that is not the case.

How should I be setting up the config registers to fire each of the pins.  Nothing else is connected to the board except the logic analyzer.

Also, how do I correlate the IQ data from the DFEPACKET.PTR to the specific antenna?

Parents
  • A result of some tests:

    I have my configuration as follows:

    NRF_RADIO->DFEMODE = RADIO_DFEMODE_DFEOPMODE_AoA;
    NRF_RADIO->DFECTRL1 = 3 << RADIO_DFECTRL1_NUMBEROF8US_Pos | 
                           1 << RADIO_DFECTRL1_DFEINEXTENSION_Pos |
                           3 << RADIO_DFECTRL1_TSWITCHSPACING_Pos |
                           1 << RADIO_DFECTRL1_TSAMPLESPACINGREF_Pos |
                           3 << RADIO_DFECTRL1_TSAMPLESPACING_Pos ;
    
    
    NRF_RADIO->CTEINLINECONF = 1 << RADIO_CTEINLINECONF_CTEERRORHANDLING_Pos |
                               0 << RADIO_CTEINLINECONF_CTEINFOINS1_Pos;

    Which gives me a response on the RX side as the following:

    Received payload:
    Buffered IQ Samples:14
    Data0: -130, 26624, 
    Data1:  -157, 9216, 
    Data2:  -96, 30208, 
    Data3:  -13, -768, 
    Data4:  1, -2816, 
    Data5:  -117, 29440, 
    Data6:  -11, 17664, 
    Data7: 1, -5376, 
    Data8:  5, -2560, 
    Data9:  -11, 17152,
    Data10: 70, 22016,
    Data11: 12, -4864,
    Data12:  5, -1536, 
    Data13:  54, 19456

    The first number is the I and the second is the Q.  With how I have the RX side configured, my NUMBEROF8US is 3, meaning I have 24uS total. The TSAMPLESPACINGRED is set to 4uS ann my TSAMPLESPACING and TSWITCHSPACING is set to 1uS intervals.

    I dont understand how I am getting 14 IQ samples. If I am getting 2 samples in my REFERENCE period, that would leave 12 samples for IQ. but then that would mean my my total time is  4uS (guard band) + 8uS (reference) + 12uS(Sample time) + 12uS ( Switching time) = 36uS.  

    Can you help shed light?

    Thanks!

  • Are you setting NRF_RADIO->DFEPACKET.MAXCNT  and then checking NRF_RADIO->DFEPACKET.AMOUNT before grabbing the samples?

Reply Children
Related