Not able to read IMU data.

[NRF52833]

Dear Team,

I have DWM3001C module which has nRF52833 chip and multiple sensors (IMU,accelerometer ,magnetometer,etc). But currently with my code, I am not able to read the data (of lis2dh12 accelerometer). I think it might be because of wrong configuration values of scl,sda and sensor address. I am attaching my code. I am getting this error :

00> <error> app: ERROR 33281 [NRF_ERROR_DRV_TWI_ERR_ANACK] at D:\nRF5_SDK_17.1.0_ddde560\nRF5_SDK_17.1.0_ddde560\examples\Myprojects\twi_scanner\main.c:88
00>
00> PC at: 0x00000623
00>
00> <error> app: End of error report

Please let me know if anyone finds the issue in the code or provide the code which directly reads the data of lis2dh12 sensor.

Thank you

Fullscreen 658022.main.c Download

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

#define TWI_INSTANCE_ID 0
#define LIS2DH12_ADDR        0x19 // I2C address of LIS2DH12
#define LIS2DH12_REG_WHO_AM_I 0x33 // Who Am I register
#define LIS2DH12_REG_CTRL_REG1 0x20 // Control Register 1
#define LIS2DH12_REG_OUT_X_L 0x28 // Output X Low register
#define LIS2DH12_REG_OUT_X_H 0x29

#include "lis2dh12.h"
#include "lis2dh12_internal.h"

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

// Function for TWI initialization
void twi_init (void)
{
    ret_code_t err_code;

    const nrf_drv_twi_config_t twi_config = {
       .scl                = SCL_PIN,
       .sda                = SDA_PIN,
       .frequency          = NRF_DRV_TWI_FREQ_400K,
       .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);

    nrf_drv_twi_enable(&m_twi);
}

static volatile bool m_xfer_done = false;
void twi_handler(nrf_drv_twi_evt_t const * p_event, void * p_context)
{
    m_xfer_done = true;
}

// Function for reading data from LIS2DH12 accelerometer
void lis2dh12_read_acceleration(int16_t *x, int16_t *y, int16_t *z)
{
    ret_code_t err_code;
    uint8_t data[6];

    // Set the address from which to read accelerometer data
    uint8_t reg_address = LIS2DH12_REG_OUT_X_L;

    // Send the register address over TWI to the accelerometer
    err_code = nrf_drv_twi_tx(&m_twi, LIS2DH12_ADDR, &reg_address, 1, true);
    APP_ERROR_CHECK(err_code);

    // Receive accelerometer data over TWI
    err_code = nrf_drv_twi_rx(&m_twi, LIS2DH12_ADDR, data, sizeof(data));
    APP_ERROR_CHECK(err_code);

    // Extract accelerometer data from received buffer
    *x = (int16_t)((data[1] << 8) | data[0]);
    *y = (int16_t)((data[3] << 8) | data[2]);
    *z = (int16_t)((data[5] << 8) | data[4]);
}

int main(void)
{
    ret_code_t err_code;
    int16_t accel_x, accel_y, accel_z;

    // Initialize logging
    APP_ERROR_CHECK(NRF_LOG_INIT(NULL));
    NRF_LOG_DEFAULT_BACKENDS_INIT();

    // Initialize TWI (I2C)
    twi_init();

    // Verify connection to LIS2DH12
    uint8_t who_am_i;
    err_code = nrf_drv_twi_rx(&m_twi, LIS2DH12_ADDR, &who_am_i, 1);
    APP_ERROR_CHECK(err_code);

     nrf_delay_ms(2);
    if (who_am_i != 0x33) {
        printf("Failed to connect to LIS2DH12\r\n");
        while (true);
    }

    // Configure accelerometer
    uint8_t ctrl_reg1_data = 0x57; // Normal mode, XYZ axes enabled, 50Hz data rate
    uint8_t reg_address = LIS2DH12_REG_CTRL_REG1;
    
    // Send control register address over TWI to the accelerometer
    err_code = nrf_drv_twi_tx(&m_twi, LIS2DH12_ADDR, &reg_address, 1, true);
    APP_ERROR_CHECK(err_code);
    
    // Write control register data
    err_code = nrf_drv_twi_tx(&m_twi, LIS2DH12_ADDR, &ctrl_reg1_data, 1, false);
    APP_ERROR_CHECK(err_code);

    printf("LIS2DH12 Accelerometer Initialized!\r\n");

    // Main loop
    while (true)
    {
        lis2dh12_read_acceleration(&accel_x, &accel_y, &accel_z);
        printf("Acceleration: X=%d, Y=%d, Z=%d\r\n", accel_x, accel_y, accel_z);
        nrf_delay_ms(1000); // Delay between readings
    }
}

.

[Håkon Alseth]

Hi,

 

I see that you're using 400 kHz mode. The internal pull resistors are too weak to be able to drive this.

Do you have external pull resistors in the range of ~5 kOhm on your SDA/SCL pins?

 

Kind regards,

Håkon

[NRF52833]

Hi,

Thanks for your reply.

Actually I have DWM3001CDK development kit which has DWM3001C module on board. So all I can do is only with the internal resistors on SDA//SCL pins. So do you have any other idea to get the data from lis2dh12 accelerometer

[NRF52833]

I even tried to flash sample twi scanner code with 100KHz mode. But its not detecting any accelerometer on the SDA/SCL pins.

[Håkon Alseth]

Hi,

 

You need to set this line:

.frequency          = NRF_DRV_TWI_FREQ_400K,

To:

.frequency          = NRF_DRV_TWI_FREQ_100K,

 

internal pull-ups are enabled in the nrfx_twi/nrfx_twim driver by default in nRF5 SDK.

 

Kind regards,

Håkon

[NRF52833]

I tried this, still the error is same:

00> <error> app: ERROR 33281 [NRF_ERROR_DRV_TWI_ERR_ANACK] at D:\nRF5_SDK_17.1.0_ddde560\nRF5_SDK_17.1.0_ddde560\examples\Myprojects\twi_scanner\main.c:88
00>
00> PC at: 0x00000623
00>
00> <error> app: End of error report
00>



 I think its not able to communicate with the accelerometer on the chip .