STEVAL-MKI209V1 board question

PDegt.1 · ‎2020-12-06

Hi,

I'm trying to evaluate IIS2ICLX sensor with this board connecting to a 3rd party MCU board, what's the best way to connect it via I2C?

I see on MKI209V1 schematics there are 2 pull up resistors already on SDA/SCL, which supposed to be connected to VDDIO (as per IIS2ICLX docs), but where are the contacts for SDA/SCL to connect to 3rd party MCU board? An example connection would be appreciated.

Thanks.

Peter BENSCH · ‎2020-12-09

As you probably know, I2C always needs pull-up resistors because the participants control the bus via open drain outputs.

You didn't mention the type of the 3rd party board yet, so no one knows if it already offers pull-ups.

Regards

/Peter

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View solution in original post

Peter BENSCH · ‎2020-12-07

You've probably confused the SDx/SCx lines with the SDA/SCL lines.

In mode 2, SDx/SCx belong to the sensor hub, which provides an I2C master for additional external sensors. These are the ones with R1/R2 pull-ups.

The connection to the host is made via SDA/SCL, which are accessible via serial resistors of 33 ohms at J1.4 / J1.6.

Regards

/Peter

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PDegt.1 · ‎2020-12-08

Could you help with a formula for tilt calculation for this sensor? I use arctan(X/Y) and readings I get don't make any sense.

Peter BENSCH · ‎2020-12-08

Please be so kind as to open a new thread with this new question as the original question appears to have been answered.

Uh, and please don't forget to close this one by choosing Select as Best.

/Peter

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PDegt.1 · ‎2020-12-09

Actually my confusion still persists - even though I'm able to read sensor's data directly from SDA/SLC lines without external pull-ups, STM docs clearly states that I have to use the pull-up resistors for I2C, page 14. So may be you could provide further clarification, or update your docs?

Peter BENSCH · ‎2020-12-09

As you probably know, I2C always needs pull-up resistors because the participants control the bus via open drain outputs.

You didn't mention the type of the 3rd party board yet, so no one knows if it already offers pull-ups.

Regards

/Peter

In order to give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.