How to measure RSSI with NRF51822?

RE: How to measure RSSI with NRF51822?

Erol CIRACI — Sun, 17 May 2015 09:37:46 GMT

my code...

void radio_init() {

radio_configure();

NRF_RADIO->SHORTS |= RADIO_SHORTS_ADDRESS_RSSISTART_Msk; //RSSI enable

NRF_RADIO->EVENTS_READY = 0U; NRF_RADIO->TASKS_RXEN = 1; // Enable radio and wait for ready.

while (NRF_RADIO->EVENTS_READY == 0U) { }

}

uint8_t radio_rssi_get (void) {

uint8_t sample;

NRF_RADIO->EVENTS_RSSIEND = 0; NRF_RADIO->TASKS_RSSISTART = 1U;

while (NRF_RADIO->EVENTS_RSSIEND == 0) { } sample = (NRF_RADIO->RSSISAMPLE & RADIO_RSSISAMPLE_RSSISAMPLE_Msk);

NRF_RADIO->EVENTS_RSSIEND = 0;

return sample;

}

void main()

{

uint8_t rssi = 0; 

NRF_CLOCK->EVENTS_HFCLKSTARTED = 0;
NRF_CLOCK->TASKS_HFCLKSTART    = 1;
  
while (NRF_CLOCK->EVENTS_HFCLKSTARTED == 0) {}

radio_init();

while(true) 
{
    rssi = radio_rssi_get();
}

}

RE: How to measure RSSI with NRF51822?

Håkon Alseth — Tue, 24 Jun 2014 14:53:42 GMT

I am sorry for misreading your question. Most likely, the RSSI of 90 is correct (actual value -90 dBm). However, note that the RSSI is only valid from -50 to -80 dBm with the resolution and accuracy given in the PS.

If you check the array, there will most likely be one or two samples that differ from the 0x5A value, especially if you change the RF channel in between every 20 samples.

RE: How to measure RSSI with NRF51822?

Nicolas — Tue, 24 Jun 2014 13:06:29 GMT

The problem is that there is no address match because I don't wait for any answer, I just want to measure if there is already something on this carrier.

RE: How to measure RSSI with NRF51822?

Håkon Alseth — Tue, 24 Jun 2014 11:21:41 GMT

Try starting the TASKS_RSSISTART when you get an address match. I've posted an example that shows how to use the RSSI here, maybe that can help you out: devzone.nordicsemi.com/.../