SPI example: MOD BLOCK Register Adress

[Christoph_I]

Hey guys,

I'm working with a Laird BL652-DVK (nrF 52832 - Chip) and Nordic SDK v.14.2.0. Now I try the SPI example and I don't know which register is adressed in the last line? I can't find it in LIS3DH-Datasheet (accelerometer).

"

//MOD BLOCK FOR NEW REG

static uint8_t       m_config_buf1[] = {0x20,0x97};   //CTRL_REG1: 9 = normal power mode (1.344kHz), Low-power Mode (5.376kHz); 7 = Z-,Y-,X-axis enable

static uint8_t       m_config_buf2[] = {0x23,0x88};   //CTRL_REG4: 8 = output registers not updated until MSB and LSB reading; 8 = high-resolution output mode enabled

static uint8_t       m_config_buf3[] = {0x22,0x10};   //CTRL_REG3: 1 = ZYXDA interrupt on INT1 enable

static uint8_t       m_config_buf4[] = {0x1F,0x80};   //TEMP_CFG_REG: 8 = ADC enabled

static uint8_t       m_config_buf5[] = {0x23,0x88};   //CTRL_REG4: 8 = output registers not updated until MSB and LSB reading; 8 = high-resolution output mode enabled

static uint8_t       m_config_buf6[] = {0xA3,0x00};  //???

"

Thanks in advance,

Christoph

[Vidar Berg]

Hi Christoph,

Is this code from a Nordic SDK? I searched through SDK 14.2.0 but couldn't find it. Also, it looks like only a few of the registers above actually match the datasheet. E.g., the address to CTRL_REG2 is 0x21 in the datasheet, but 0x23 in the code.

Best regards,

Vidar

[Christoph_I]

Hey Vidar,

Yes it's from the SPI example (.../examples/peripheral/spi). The whole code is below.

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#include <nrf_drv_spi.h>
#include "app_util_platform.h"
#include "nrf_gpio.h"
#include "nrf_delay.h"
#include "boards.h"
#include "app_error.h"
#include <string.h>
#include "nrf_log.h"
#include "nrf_log_ctrl.h"
#include "nrf_log_default_backends.h"
#include <stdint.h>
#include <stdbool.h>

#define SPI_INSTANCE  0 /**< SPI instance index. */
static const nrf_drv_spi_t spi = NRF_DRV_SPI_INSTANCE(SPI_INSTANCE);  /**< SPI instance. */
static volatile bool spi_xfer_done = false;  /**< Flag used to indicate that SPI instance completed the transfer. */

//MOD BLOCK FOR NEW REG

static uint8_t       m_config_buf1[] = {0x20,0x97};
static uint8_t       m_config_buf2[] = {0x23,0x88};
static uint8_t       m_config_buf3[] = {0x22,0x10};
static uint8_t       m_config_buf4[] = {0x1F,0x80};
static uint8_t       m_config_buf5[] = {0x23,0x88};
static uint8_t       m_config_buf6[] = {0xA3,0x00};

uint8_t read_data[7];

static uint8_t		 m_get_buf1[] = {0xE8,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xAA,0xAA,0xAA,0xAA,0xAA,0xAA,0xAA};



void config_accel(){

    nrf_drv_spi_transfer(&spi, m_config_buf1, sizeof(m_config_buf1), NULL, 0);
    nrf_delay_us(160);
    nrf_drv_spi_transfer(&spi, m_config_buf2, sizeof(m_config_buf2), NULL, 0);
    nrf_delay_us(160);
    nrf_drv_spi_transfer(&spi, m_config_buf3, sizeof(m_config_buf3), NULL, 0);
    nrf_delay_us(160);
	nrf_drv_spi_transfer(&spi, m_config_buf4, sizeof(m_config_buf4), NULL, 0);
    nrf_delay_us(160);
    nrf_drv_spi_transfer(&spi, m_config_buf5, sizeof(m_config_buf5), NULL, 0);
    nrf_delay_us(160);
    nrf_drv_spi_transfer(&spi, m_config_buf6, sizeof(m_config_buf6), NULL, 0);
    nrf_delay_ms(1000);

}

void get_accel(){
	while (1){
				nrf_drv_spi_transfer(&spi, m_get_buf1, sizeof(m_get_buf1), read_data, sizeof(read_data));
	    		nrf_delay_ms(20);
	        }
}

void spi_event_handler(nrf_drv_spi_evt_t const * p_event,
                       void *                    p_context)
{
    spi_xfer_done = true;
}

int main(void)
{

    nrf_drv_spi_config_t spi_config = NRF_DRV_SPI_DEFAULT_CONFIG;
    spi_config.ss_pin   = 22;
    spi_config.miso_pin = 24;
    spi_config.mosi_pin = 23;
    spi_config.sck_pin  = 25;
	spi_config.frequency = NRF_DRV_SPI_FREQ_2M;
    spi_config.mode     = NRF_DRV_SPI_MODE_3;
    nrf_drv_spi_init(&spi, &spi_config, spi_event_handler, NULL);

	config_accel();

	get_accel();
}

I just see that there is nothing in the description of an acceleration sensor or that an acceleration sensor should be adressed. Do you know which sensor is adressesd / should be adressed with the SPI example? (I want to address an accelerometer.)

And you are right, some adresses are missing. I think that these addresses will not be changed and should remain set to default.

Best regards,

Christoph

[Vidar Berg]

Hi Christoph,

I'm confused, the code you posted is not from the original SDK example. Did you define the m_config_buf[] arrays yourself or is it from a third party? 

[Christoph_I]

Hi Vidar,

apologize, you are right. I got the project from a colleaguq without a note or explanation. So I assumed that the SPI example was not modified. But after you wrote that you can not find my code, I started to ponder and I downloaded the SDK v.14.2.0 again and looked it up in main.c. The result: my SPI example was modfied by my colleague. I'm sorry and thank you for your help.

I wish you a nice thursday and Merry Christmas.

Christoph

[Vidar Berg]

Hi Christoph,

No worries. That explains everything, thanks for the update. And Merry Christmas to you.

Vidar