LPS33HW I2C mode with STEVAL-MKI109V3

[Jacek Pieczaba]

Hello,

I would like to ask you a question. I would like to use the LPS33HW in my application with I2C bus, before I move with the software development I would like to check if the sensor works with given ambient conditions. I thought that it will be great if I can reuse the STEVAL-MKI109V3 board and the GUI to read the data. Unfortunately I cannot connect with the sensor if I am do it like on schematic ( see attach ). Could you be so kind and help me to understand what I should do in order to verify if the sensor sense 🙂

Thank you in advance

Jacek Pieczaba

[AvaTar]

> Unfortunately I cannot connect with the sensor if I am do it like on schematic ( see attach ).

What exactly is the problem ?

You will need pull-up resistors for I2C to work. There are none in the schematics.

[Miroslav BATEK]

@Community member​  the pull-up resistors are on the STEVAL-MKI109V3

@Jacek Pieczaba What is the error message you get from Unico? Do you have the latest version of the firmware in the ​STEVAL-MKI109V3?

[Jacek Pieczaba]

Hello,

Thank you very much for the suggestions what to check. In the mean time I was working on this problem with application engineer from ST and we figure out what to do in order to make it works. I just wanted to share the solution :

• Connect the GNDs (pin 13 on the MKI109 )
• Lower the VDD on your board to 1.8V ( pin 1 on the MKI109 ) - removed the LDO and connect straight sensor with connector
• SD0 pin I tight to via 10k to 1.8V ( I have disconnect this line from MKI109 and place the pullup resistor on my board )

After this modification external boards with Sensor works very well under the GUI which is exactly what I wanted to obtain.

Thank you very much

Jacek Pieczaba

ps. Miroslav before I get an error ( see attached ) , version of Unico 7.0.0.0