APP_ERROR_CHECK(nrf_drv_spi_transfer(&spi, m_tx_buf, m_length, m_rx_buf, m_length));

[YASH]

Hi All,

I am a beginner,Can you please explain me what is the role of this line?

APP_ERROR_CHECK(nrf_drv_spi_transfer(&spi, m_tx_buf, m_length, m_rx_buf, m_length));

[YASH]

This is how my main(void) looks like:-

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

NRF_LOG_INFO("SPI example\r\n");

nrf_drv_spi_config_t spi_config = NRF_DRV_SPI_DEFAULT_CONFIG;
spi_config.ss_pin   = ARDUINO_4_PIN;
spi_config.miso_pin = ARDUINO_12_PIN;
spi_config.mosi_pin = ARDUINO_11_PIN;
spi_config.sck_pin  = ARDUINO_13_PIN;
APP_ERROR_CHECK(nrf_drv_spi_init(&spi, &spi_config, spi_event_handler));

//CHANGES ENDS HERE
	
while (1)
{
  //Reset rx buffer and transfer done flag			 
		memset(m_rx_buf, 0, m_length);
  spi_xfer_done = false;
		 		 
 		//SDC Main starts here
		 
	  APP_ERROR_CHECK(nrf_drv_spi_transfer(&spi, m_tx_buf, m_length, m_rx_buf, m_length));

    while (!spi_xfer_done)
			{
		     __WFE();
    }
	  bsp_board_leds_init();

  APP_ERROR_CHECK(NRF_LOG_INIT(NULL));
  NRF_LOG_INFO("\r\nFATFS example.\r\n\r\n");

  fatfs_example();
	
  APP_ERROR_CHECK(nrf_drv_spi_transfer(&spi, m_tx_buf, m_length, m_rx_buf, m_length));

  while (!spi_xfer_done)
  {
        __WFE();
    }
		 
		memset(m_rx_buf, 0, m_length);
  spi_xfer_done = false;

		nrf_drv_spi_switch_chips(&spi, SPI_SS_PIN_1);
		 
	  //static const nrf_drv_spi_t spi = NRF_DRV_SPI_INSTANCE(1); 
		 
  APP_ERROR_CHECK(nrf_drv_spi_transfer(&spi, m_tx_buf, m_length, m_rx_buf, m_length));

  while (!spi_xfer_done)
  {
        __WFE();
  }

  ssd1306_power_on();
    ssd1306_init(SSD1306_CONFIG_DC_PIN,
               SSD1306_CONFIG_RST_PIN,
               SSD1306_CONFIG_CS_PIN,
               SSD1306_CONFIG_CLK_PIN,
               SSD1306_CONFIG_MOSI_PIN);
    ssd1306_begin(SSD1306_SWITCHCAPVCC, SSD1306_I2C_ADDRESS, true);
	
	  init_text();
    ssd1306_clear_display();
  ssd1306_set_textsize(2);
  ssd1306_set_textcolor(WHITE);
  ssd1306_set_cursor(10, 0);
  
	  ssd1306_display();
	
	  show_text();
	  
		//APP_ERROR_CHECK(nrf_drv_spi_transfer(&spi, m_tx_buf, m_length, m_rx_buf, m_length));
		
	  while(spi_xfer_done)
	  {
		
	    if(button_pressed) 
				{
			  show_text();
			  button_pressed = false;
		    }
    		__WFE();
				
	  //SDC Main Code ends here
  		  power_manage();
	  }
 }

}