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VKoga.1
Associate II
September 11, 2021
Solved

Use of DRDY_M & DEN_A/G in LSM9DS1?

  • September 11, 2021
  • 6 replies
  • 2371 views

I am trying to build custom boards using LSM9DS1, I shot through the data sheet, but the information on these two pins is not clear enough? What is the purpose of these pins(DRDY_M & DEN_A/G)?

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Best answer by Eleon BORLINI

Hi @VKoga.1​ ,

  • the DEN_A/G pin can be used as data ready output for the accelerometer/gyro part of the module: its purpose is to synchronize the measurement with external signal, and if you don't need this functionality you can keep it unconnected. To enable this functionality you have to configure it in the proper registers, but you can use as well the INT1 and INT2 pins.
  • the DRDY_M is the magnetometer "sub-chip" data ready output (that goes up when the magnetometer data is available, if properly configured), and has the same functionality as the DEN_A/G of the accelerometer/gyro but for the magnetic sensor.

These pins can appear quite not useful, but are used for debug and test mode purposes.

If my reply answered your question, please click on Select as Best at the bottom of this post. This will help other users with the same issue to find the answer faster. 

-Eleon

6 replies

Eleon BORLINI
Eleon BORLINIBest answer
ST Employee
September 14, 2021

Hi @VKoga.1​ ,

  • the DEN_A/G pin can be used as data ready output for the accelerometer/gyro part of the module: its purpose is to synchronize the measurement with external signal, and if you don't need this functionality you can keep it unconnected. To enable this functionality you have to configure it in the proper registers, but you can use as well the INT1 and INT2 pins.
  • the DRDY_M is the magnetometer "sub-chip" data ready output (that goes up when the magnetometer data is available, if properly configured), and has the same functionality as the DEN_A/G of the accelerometer/gyro but for the magnetic sensor.

These pins can appear quite not useful, but are used for debug and test mode purposes.

If my reply answered your question, please click on Select as Best at the bottom of this post. This will help other users with the same issue to find the answer faster. 

-Eleon

VKoga.1
VKoga.1Author
Associate II
September 14, 2021

@Eleon BORLINI​ Okay, so leave both the pins floating if you want to use interrupt pins.

VKoga.1
VKoga.1Author
Associate II
September 14, 2021

@Eleon BORLINI​ How are they used for debug & testing purpose? is it not more efficient to just probe the INTx M(or)A/G pins using a oscilloscope?

Eleon BORLINI
ST Employee
September 15, 2021

Hi @VKoga.1​ ,

This use is internal to ST only, not accessible to the customer.

-Eleon

VKoga.1
VKoga.1Author
Associate II
September 15, 2021

@Eleon BORLINI​ should I just leave them float/ no connect??

Eleon BORLINI
ST Employee
September 15, 2021

Hi @VKoga.1​ ,

if you are sure you don't need them, you can leave unconnected. Usually however they are connected to the application processor in case of future needs.

-Eleon