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Neha Tawale
Neha Tawale
Associate
Jan 10, 2018 9:32 AM UTC
Question

LIS2DH12 is always returning only 0x80,0x40,0xC0 values in receive buffer of spi

Posted on January 10, 2018 at 10:32

I am trying to interface LIS2DH12 with NRF51822 chip using SPI communication no matter in what way i configure my spi, it is always returning fixed values 0x80,0x40,0xc0 in all six registers for x,y,z co-ordinate.

I am not using FIFO but trying directly to read from register is it right way or should i choose FIFO mode.

thanks in advance.

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    6 replies

    Miroslav BATEK
    ST Employee
    Jan 10, 2018 9:48 AM UTC
    Posted on January 10, 2018 at 10:48

    To check your SPI communication first try to read who_am_i (0x0F) register, if it works then try to write a value to a register and read it back.

    If this works, please share you sensor configuration and I can check it.

    Neha Tawale
    Neha TawaleAuthor
    Associate
    Jan 10, 2018 10:00 AM UTC
    Posted on January 10, 2018 at 11:00

    Thanks for your attention and I am able to read value 0x33 from WHO_M_I register as well as able to write and read from any register.

    This are my MEMS configuration function:

    void MCAL_MEMS_Init()

    {

    int i;

    /* MEMS Configuration Register */

    LIS2DH12_Write( LIS2DH12_REG_CTRL_REG1,0x77);

    for(i=0;i<100;i++);

    LIS2DH12_Write( LIS2DH12_REG_CTRL_REG2,0x00);

    for(i=0;i<100;i++);

    LIS2DH12_Write( LIS2DH12_REG_CTRL_REG4,0x00);

    for(i=0;i<100;i++);

    LIS2DH12_Write( LIS2DH12_REG_CTRL_REG5,0x00);

    for(i=0;i<100;i++);

    LIS2DH12_Write( FIFO_CTRL_REG ,0x00);

    for(i=0;i<100;i++);

    LIS2DH12_Write( TEMP_CFG_REG ,0x00);

    for(i=0;i<100;i++);

    LIS2DH12_Write( INT1_CFG ,0x00);

    for(i=0;i<100;i++);

    }

    Please suggest me if i am doing anything wrong in configuring MEMS registers.

    Miroslav BATEK
    ST Employee
    Jan 10, 2018 11:26 AM UTC
    Posted on January 10, 2018 at 11:26

    You configuration is correct, only set the CTRL_REG1 is enough to make the sensor work, other registers are in default value.

    Are you sure you you are reading the correct output registers. You wrote that you read 3 values (0x80, 0x40, 0xC0) in all six registers, it doesn't make much sense. What are the values in all six registers? Are they stable?

    Neha Tawale
    Neha TawaleAuthor
    Associate
    Jan 11, 2018 3:45 AM UTC
    Posted on January 11, 2018 at 04:45

    Thanks for your attention again and for testing purpose if i check only one register suppose OUT_X_L or any other it will return those values(0x80,0x40,0xc0) which is not right i guess, i am suppose to get variable and not fix values in these registers on movement of the sensor.

    What could be the possible reason if u can tell.

    Miroslav BATEK
    ST Employee
    Jan 11, 2018 9:20 AM UTC
    Posted on January 11, 2018 at 09:20

    Unfortunately, your explanation is not clear. I think, the sensors works, you only misinterpret the results.

    Please read all six output registers (during movement or in different sensor position) and share the values, I can then check it.

    olin00
    Visitor II
    Sep 16, 2023 7:06 PM UTC

    I had the same issue using I2C - the XYZ values received by reading 6 bytes in one go were as Neha Tawale described. In my case the solution was to enable automatic incrementation of the address register by adding 0x80 to the address value.

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