reading external sensor using i2c

[ps_anu]

hi...

i want to read the  external accelerometer sensor using i2c in nRF52832 ..how to do ?

[ps_anu]

Hi... Amanda

i tried .. but i am getting constantly 0 as a value . see the code 

#include <stdio.h>
#include "boards.h"
#include "app_util_platform.h"
#include "app_error.h"
#include "nrf_drv_twi.h"
#include "nrf_delay.h"


#include "nrf_log.h"
#include "nrf_log_ctrl.h"
#include "nrf_log_default_backends.h"

/* TWI instance ID. */
#define TWI_INSTANCE_ID     0

/* Common addresses definition for temperature sensor. */


/* Mode for LM75B. */
#define NORMAL_MODE 0U

/* Indicates if operation on TWI has ended. */
static volatile bool m_xfer_done = false;

/* TWI instance. */
static const nrf_drv_twi_t m_twi = NRF_DRV_TWI_INSTANCE(TWI_INSTANCE_ID);

/* Buffer for samples read from temperature sensor. */
static uint8_t m_sample;








uint32_t device_addr    =0x4C ;

 uint32_t register_addr= 0x00;

 uint8_t *p_data;


void twi_init (void)
{
    ret_code_t err_code;

    const nrf_drv_twi_config_t twi_config  = {
       .scl                = ARDUINO_SCL_PIN,
       .sda                = ARDUINO_SDA_PIN,
      .frequency          = NRF_DRV_TWI_FREQ_100K,
       .interrupt_priority = APP_IRQ_PRIORITY_HIGH,
       .clear_bus_init     = false
    };

     err_code = nrf_drv_twi_init(&m_twi, &twi_config, NULL, NULL);
   
    APP_ERROR_CHECK(err_code);
    if (NRF_SUCCESS == err_code)
	{
		nrf_drv_twi_enable(&m_twi);
		NRF_LOG_INFO("TWI init success...");	
}
}


static void read_register()
{
  ret_code_t err_code;
  nrf_drv_twi_t twi_instance;
  uint32_t device_addr    =0x4C ;


 uint32_t register_addr=   0x00;
  uint8_t *p_data; uint8_t bytes;
  bool no_stop;

 err_code = nrf_drv_twi_tx(&twi_instance, device_addr, &register_addr, 1, no_stop);
  APP_ERROR_CHECK(err_code);

  if(err_code != NRF_SUCCESS) {
    return err_code;
  }
  err_code = nrf_drv_twi_rx(&twi_instance, device_addr, p_data, bytes);
return err_code;
}




int main(void)
{
    APP_ERROR_CHECK(NRF_LOG_INIT(NULL));
    NRF_LOG_DEFAULT_BACKENDS_INIT();

    NRF_LOG_INFO("\r\nTWI sensor example started.");
    NRF_LOG_FLUSH();
    twi_init();
   read_register();

   
    while (1)
    {
        nrf_delay_ms(500);
           NRF_LOG_INFO("\r\nTWI .");
printf("p_data:%d",p_data);
NRF_LOG_INFO("P_data:%d",p_data);
NRF_LOG_FLUSH();
    
}
}