Showing results for 
Search instead for 
Did you mean: 

LSM330DLC data sheet questions

Posted on November 07, 2013 at 19:32


I need to configure a LSM330DLC in a way outlined in the DT0005 document.  Essentially, on data ready interrupts (INT1_A) from the accelerometer feed into the DEN_G pin, telling the gyro to push a conversion onto the gyro FIFO.  In this way, acceleration and gyro data are aligned (I think).

In addition, I want to have a FIFO watermark interrupt as well as an interrupt to wake my board up upon movement.

I believe I need to setup three interrupts sources:

1) INT1_A to be I1_DRDY1 (or is it I1_DRDY2?)  Which one does what?

2) INT2_A to fire upon a motion detection event.  I believe I see how to do this with INT1_A, but I need it to happen on INT2_A.

3) A FIFO watermark interrupt to fire from the gyro side (INT2_G).  This one I have figured out, but need INT1_A/DEN_G working before I can fully test it.

More to the point-

1) In table 18, there are INT2_CFG_A, SOURCE_A, etc registers, but I see no mention of them in the section 8 description.  Does anyone know how to configure INT2 on the accelerometer.

2) What is the difference between DRDY1 and DRDY2? (See table 26).  In short, how do I make INT1_A fire upon every accel conversion?

3) The text after table 43 ''The content of this register is loaded at boot?''  OK, so if I want to change it do I need to reboot for the changes to take place?  I also do not see in table 18 which registers are actually loaded at boot.

4) If I am doing it properly, rebooting does not appear to wipe out FIFO count.  Is this the correct behavior.

5) What does Figure 20 mean?

Thank you in advance for your help,


#lsm330dlc-drdy-interrupt #lsm330-lsm330dlc
Thiago REIS
Associate II
Posted on January 06, 2014 at 12:23

Hello Shane,

You can use the Accel to trigger an interrupt on a motion with the data ready signal, so this should be ok. However when the DEN_G pin on the gyro will not make the gyro FIFO fill up, you have two ways of using the DEN_G pin, either continuous sampling with the last bit (b0) telling you if the gyro data was coming from DEN = 1 or DEN = 0, so you will have to do a data post processing to find out what happened, and then the other way is DEN on rising edge which sample a single data.

So let me know if you want me to send you an example of motion wakeup.

Here is my recommendation:

  • Set the Accel in motion wakeup with INT1 connected to DEN_G

  • Set the gyro DEN in to have a continuous sampling

Also regarding your question, INT2 can be latched by set bit 1 of REG5_A.

Thank you,

Thiago Reis

Posted on February 04, 2014 at 06:57


Could me some sample code showing how to set up INT1_A to fire for each acclerometer conversion?


Thiago REIS
Associate II
Posted on February 05, 2014 at 13:53

Hello Brian,

Did you have a chance to check the sample codes available for ST´s Accelerometers in the Accelerometers Forum´s section?

Thank you,


Posted on February 06, 2014 at 07:35

Hi Thiago,

I saw some examples in the accelerometer section, but they didn't help me. I can make the FIFO overflow interrupt work, but not the DRDY1 or DRDY2. Do these interrupts require additional register settings? I am not looking for any threshold or duration parameters to be met. I just want an interrupt for each accelerometer sample as it goes into the FIFO.



Posted on April 07, 2014 at 23:24

I have the same question as Brian.

Associate II
Posted on May 22, 2014 at 03:13

Hi Thiago,

Is there some description of what the DEN_G pin does and how to use it for the LSM9DS0 sensor? I would very much like to take advantage of what I think the capability is for the LSM9DS0 sensor but I can find no documentation nor any example of how to configure the device or its registers for use of the DEN_G pin. Please help. Thank you.


A Pantsalot
Posted on October 23, 2017 at 19:21

Hello,  I have some questions about LSM330DLC datasheet:

  1. The INT1_A, INT2_A, INT1_G, INT2_G pins have Disable/Enable bits in their respective registers.  Does setting the Disable/Enable bit tri-state the respective pin?

  2. CTRL_REG3_G has a PP_OD bit.  Which interrupt is that for?  Or is it for all 4 interrupts?

Posted on October 24, 2017 at 16:14

If none of the interrupt is enabled the INT pin is pulled down to ground, so it is not in high impedance state.

PP_OD bit in CTRL_REG3_G register configures both gyroscope interrupt pins (INT1_G,DRDY_G\INT2_G) .