LSM6DS3 EVB "STEVAL-MKI160V1" communication issue using SPI 4 wire

[SChin.2]

Hello ST

here am using STEVAL-MKI160V1 in which LSM6DS3 is placed and an trying communicate with it over SPI.

Physical connections:

• CS- CS
• SCL- CLK
• SDA - SDO of mc
• SDO - SDI of mc
• VDD - 3.3V
• GND - GND

SPI Configuration:

• SPI Freq- 1MHZ
• Slave Select - Active low
• Clock Phase - Read on ODD edge
• clock polarity - Active High
• bit order - MSB first

Am sending command "0x8F00"(WHO AM I-0F) over MOSI line and am not able to see response "0x0069" instead am seeing 0x0B00/0x0F00/0x0000 etc.. which is not consistent, I believe all the responses are wrong. Do I missing something in Physical connections or doing something wrong in SPI config ?. please help me

Seen VDDIO voltage level is 5V with out having any connection on it , but still VDDIO max is 3.7 as per data sheet , is that the issue ?

Do I need to make any additional connections or circuit on OCS/SCx/SDx/OSDO ??

Please do the needfull.

[SChin.2]

Hello @Eleon BORLINI​ 

Sorry for delay in giving the response !

Yes, without knowing my SPI line logic level's are 5V. Now I have corrected the logic levels & on sending 0x8F00(WHO AM I) am seeing not valid data , the received data is random.

Is their any way to test or check the part health ?. But still in previous case as we see the voltage levels on pins are at 4.2V, data sheet says it should not exceed 4.8V.

[Eleon BORLINI]

Hi @SChin.2​ ,

First time -above in your first post- you wrote:

>> Seen VDDIO voltage level is 5V with out having any connection on it

This is above the absolute maximum rating...

Are the Vdd and VddIO both below 3.6V now?

A check on the SPI mode you are using:

• Clock Phase - Read on ODD edge
• Clock polarity - Active High

Odd edge is, if I'm not wrong, the falling edge, so you are using SPI mode 2, right? However, as described in the datasheet p. 25, the SPI required for the id the Mode 3, i.e. data are sampled on the rising edge and shifted out on the falling edge. Could you try this Mode or share the digital waveform patterns of your SPI communication?

-Eleon

[SChin.2]

Hi @Eleon BORLINI​ 

We have got the new part since the last one was got damaged because of 5v supply on VDDIO

But still we are seeing same issue in getting the response for WHO AM I,

SPI Configuration:

• SPI Freq- 100KHZ
• Slave Select - Active low
• CPHA- 1
• CPOL - 1
• bit order - MSB first

sent 0x8F00 on MOSI line and seen 0x0040 and it was random some times we are seeing 0x007F as a response.

  

[Eleon BORLINI]

Hi @SChin.2​ ,

So there was also a problem related to 5V Vdd / VddIO voltage...

I saw you (correctly) published a new post on this topic here.

I'll go there for the (tentative) answer.

-Eleon