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MKhur.1211
Visitor II
November 15, 2019
Question

I2C communication issue with H3LIS331DL and/or LSM9DS1TR chips.

  • November 15, 2019
  • 1 reply
  • 636 views

I’m trying to read 6 memory addresses I series. They represent appropriate X, Y, Z Accelerations levels.

At low speed – up to 50kbps all good and working correctly. However if I increase I2C speed – up to 400 kbps, then I see wrong data being sent from Accelerometer chips.

This was verified on multiple prototypes. Communication lines quality is good and signals are clean on Oscilloscope.

See attached picture. It seems like on higher speeds (400 kbps) chip is missing to send very first byte (low byte of X acceleration).

Do you know what can be issue here and how to solve it.0690X00000As41GQAR.png

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    1 reply

    E
    Eleon BORLINI
    ST Employee
    November 19, 2019

    Hi @MKhur.1211​ , It is very strange that a full 8-bit register value is missing just increasing the I2C communication speed... I would have expected a different shaping of the SCL / SDA edges or something like this. We have no evidence of missing samples in continuous mode, regardless the I2C speed... Are you working in continuous or FIFO mode? And, if it is possible for you, can you try to read data in SPI mode (which can go much faster than the I2C)? Regards

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