How to completely power down the lsm9ds1?

[PRebo.1]

I'm using the lsm9ds1 as part of a bought module - the arduino nano 33 ble - which can achieve very low power (micro amps) in a power down mode.

However, If I initialize and read accel and gyro data from the IMU, afterwards I can't find a way to get back to those low values and I get stuck in the milliamps.

What sequence of writes should I send to the LSM registers in order to power it down as much as possible?

I'm currently using this sequence for the power down:

LSM9DS1_CTRL_REG3_M = 0x03

LSM9DS1_CTRL_REG1_G = 0x00

LSM9DS1_CTRL_REG6_XL = 0x00

NOTE- the mcu communicates with the LSM using i2c.

[Eleon BORLINI]

Hi @PRebo.1​ , the register settings seem OK... are all the other register to zero 00h or in their default configuration? I suggest you to try to pass through a SW reset by enabling the SW_RESET bit in CTRL_REG8 (22h) register. You can also check the standard C mems drivers on Github for the LSM9DS1 module (LINK).

/**
  * @brief  Software reset. Restore the default values in user registers.[set]
  *
  * @param  ctx_mag   Read / write magnetometer interface definitions.(ptr)
  * @param  ctx_imu   Read / write imu interface definitions.(ptr)
  * @param  val    Change the values of sw_reset in reg CTRL_REG8.
  * @retval        Interface status (MANDATORY: return 0 -> no Error).
  *
  */
int32_t lsm9ds1_dev_reset_set(stmdev_ctx_t *ctx_mag, stmdev_ctx_t *ctx_imu,
                              uint8_t val)
{
  lsm9ds1_ctrl_reg2_m_t ctrl_reg2_m;
  lsm9ds1_ctrl_reg8_t ctrl_reg8;
  int32_t ret;
 
  ret = lsm9ds1_read_reg(ctx_imu, LSM9DS1_CTRL_REG8, (uint8_t*)&ctrl_reg8, 1);
  if(ret == 0){
    ctrl_reg8.sw_reset = (uint8_t)val;
    ret = lsm9ds1_write_reg(ctx_imu, LSM9DS1_CTRL_REG8,
                            (uint8_t*)&ctrl_reg8, 1);
  }
  if(ret == 0){
    ret = lsm9ds1_read_reg(ctx_mag, LSM9DS1_CTRL_REG2_M,
                           (uint8_t*)&ctrl_reg2_m, 1);
  }
  if(ret == 0){
    ctrl_reg2_m.soft_rst = (uint8_t)val;
    ret = lsm9ds1_write_reg(ctx_mag, LSM9DS1_CTRL_REG2_M,
                            (uint8_t*)&ctrl_reg2_m, 1);
  }
 
  return ret;
}

Regards

[PRebo.1]

Thank you.

In the end the problem was elsewhere.