Problem facing with RSSI value in nRF51822

[kvrb]

Hi,

I am new to nRF microcontroller and communication . currently, I am working on nRF51822 microcontroller. I am able to communicate between two nRF51822 microcontrollers(without any protocol stack).

I want to measure RSSI value. I got RSSI new 1test.ccode from the nordic website. When I integrated RSSI code with my code, I got constant RSSI value that is 46. I didn't know what is the mistake. I have attached my code with this.

[kvrb]

Hi Sigurd,

I try the same function in my code.

I am getting constant value 46 every time.

This is my code:

#include <stdint.h>
#include <stdbool.h>
#include <stdio.h>
#include "radio_config.h"
#include "nrf_gpio.h"
#include "boards.h"
#include "bsp.h"
#include "app_timer.h"
#include "nordic_common.h"
#include "nrf_error.h"
#include "nrf_delay.h"

#define APP_TIMER_PRESCALER      0                     /**< Value of the RTC1 PRESCALER register. */
#define APP_TIMER_OP_QUEUE_SIZE  2                     /**< Size of timer operation queues. */

#define UART_TX_BUF_SIZE 256                           /**< UART TX buffer size. */
#define UART_RX_BUF_SIZE 1                             /**< UART RX buffer size. */

static uint32_t                   packet;              /**< Packet to transmit. */

void uart_error_handle(app_uart_evt_t * p_event)
{
   // No implementation needed.
}

/**@brief Function for initialization oscillators.
 */
void clock_initialization()
{
    /* Start 16 MHz crystal oscillator */
    NRF_CLOCK->EVENTS_HFCLKSTARTED = 0;
    NRF_CLOCK->TASKS_HFCLKSTART    = 1;

    /* Wait for the external oscillator to start up */
    while (NRF_CLOCK->EVENTS_HFCLKSTARTED == 0)
    {
        // Do nothing.
    }

    /* Start low frequency crystal oscillator for app_timer(used by bsp)*/
    NRF_CLOCK->LFCLKSRC            = (CLOCK_LFCLKSRC_SRC_Xtal << CLOCK_LFCLKSRC_SRC_Pos);
    NRF_CLOCK->EVENTS_LFCLKSTARTED = 0;
    NRF_CLOCK->TASKS_LFCLKSTART    = 1;

    while (NRF_CLOCK->EVENTS_LFCLKSTARTED == 0)
    {
        // Do nothing.
    }
}


/**@brief Function for reading packet.
 */
uint32_t read_packet()
{
    uint32_t result = 0;

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

    while (NRF_RADIO->EVENTS_READY == 0U)
    {
        // wait
    }
    NRF_RADIO->EVENTS_END = 0U;
    // Start listening and wait for address received event
    NRF_RADIO->TASKS_START = 1U;

    // Wait for end of packet or buttons state changed
    while (NRF_RADIO->EVENTS_END == 0U)
    {
        // wait
    }

    if (NRF_RADIO->CRCSTATUS == 1U)
    {
        result = packet;
    }
    NRF_RADIO->EVENTS_DISABLED = 0U;
    // Disable radio
    NRF_RADIO->TASKS_DISABLE = 1U;

    while (NRF_RADIO->EVENTS_DISABLED == 0U)
    {
        // wait
    }
    return result;
}

uint8_t radio_rssi_get (void) {

uint8_t sample;
NRF_RADIO->TASKS_RSSISTART = 1;
while (NRF_RADIO->EVENTS_RSSIEND == 0){}
NRF_RADIO->EVENTS_RSSIEND = 0;
sample = NRF_RADIO->RSSISAMPLE;
NRF_RADIO->TASKS_RSSISTOP = 1;
return sample;

}


/**
 * @brief Function for application main entry.
 * @return 0. int return type required by ANSI/ISO standard.
 */
int main(void)
{
    uint32_t err_code = NRF_SUCCESS;
	//nrf_gpio_cfg_output(23); // Making LED port pin to output
	uint8_t rssi = 0; 

    clock_initialization();
    APP_TIMER_INIT(APP_TIMER_PRESCALER, APP_TIMER_OP_QUEUE_SIZE, NULL);

    const app_uart_comm_params_t comm_params =  
    {
        RX_PIN_NUMBER, 
        TX_PIN_NUMBER, 
        RTS_PIN_NUMBER, 
        CTS_PIN_NUMBER, 
        APP_UART_FLOW_CONTROL_DISABLED, 
        false, 
        UART_BAUDRATE_BAUDRATE_Baud115200
    };   
    APP_UART_FIFO_INIT(&comm_params, 
                       UART_RX_BUF_SIZE, 
                       UART_TX_BUF_SIZE, 
                       uart_error_handle, 
                       APP_IRQ_PRIORITY_LOW,
                       err_code);
    APP_ERROR_CHECK(err_code);
    err_code = bsp_init(BSP_INIT_LED, APP_TIMER_TICKS(100, APP_TIMER_PRESCALER), NULL);
    APP_ERROR_CHECK(err_code);

    // Set radio configuration parameters
    radio_configure();
    NRF_RADIO->PACKETPTR = (uint32_t)&packet;

    err_code = bsp_indication_text_set(BSP_INDICATE_USER_STATE_OFF, "Wait for first packet\n\r");
    APP_ERROR_CHECK(err_code);

    while (true)
    {
		uint32_t received = read_packet();
		
        nrf_delay_ms(500);
        printf("The contents of the package is %u\n\r", (unsigned int)received);
		
		rssi = radio_rssi_get();
		 printf("RSSI = %d\n\r", rssi);
		
    }
}