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LSM9DS1 SPI not working

Question asked by Scianni.Vincenzo on Feb 26, 2017
Latest reply on Mar 2, 2017 by Scianni.Vincenzo

Hello.

I´m having problems on SPI reading WHO_AM_I register of a LSM9DS1 mounted on STEVAL-MKI159V1 : the correct answer is 0x68 but very often I got 0x28. The suspect that the level of bit 6 was not correctly set is confirmed by some traces of the oscilloscope but I need to say that:

 

1) Attaching probes fixes the problem : for some reasons the loads of probes solve the problem.

 

2) I got the two attached pictures during the initialization of the board or shaking a little bit cables of a second circuit on a breadboard.

 

  Summarizing the situation : in normal condition I got very often the incorrect value 0x28 but when I connect probes the problem disappears and I have always the correct value 0x68. Only in some conditions - initialization phase in the first 10 seconds or shaking a little bit some connection cables of a breadboard - I got the two attached pictures. I read a post of an user with a similar problem but the conclusion of the story was a suspected damage of the component during the soldering : in my case I bought two STEVAL-MKI159V1 and both have the same problem ...

Let me close adding that I connected STEVAL to a Pic18F25K80 with a SPI clock at 4 MHz.

 

Thank you and best regards,

Scianni Vincenzo

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