Maximilian Ogris

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5 years, 6 months ago.

I have SPI connection Problems with the LSM6DS3

Hey, I bought a LSM6DS3 Board at sparkfun.

Here is the datasheet to the board: More about SPI https://www.st.com/resource/en/datasheet/lsm6ds3.pdf

Connection: 3V3 - 3V3 GND - GND SCL-p13 SDA(SDI)-p11 CS-p14 SA0-p12

My Programm returns everytime 0x7F

Here is my Code:

its not working :(

#include "mbed.h"

Serial pc(USBTX,USBRX);
SPI spi(p11, p12, p13); // mosi, miso, sclk
DigitalOut cs(p14);


int main() {
    pc.baud(115200);
    pc.printf("Start");
    spi.format(8,3);
    spi.frequency(100000); 
    // Select the device by seting chip select low
    cs = 1;
    wait(1); 
    uint8_t result;       
    while(1){
        //Select chip
        cs = 0;
        //Read (0x80||Address)
        //Write (0x00||Address)
        spi.write(0x8F);
        // send a dummyvalue of 0 to read the first byte returned:
        result = spi.write(0x00);
        //deselect chip
        cs = 1;
        // Send 0x8f, the command to read the WHOAMI register
        printf("WHOAMI register = 0x%X  \n ", result);
         wait_ms(1);
        // Deselect the device
    }
}

1 Answer

Jan Kamidra
5 years, 6 months ago.

Hi there,

you can try to find a library or a Demo here on the Mbed web. For example...

Import libraryLSM6DS3

LSM6DS3 Library

Last commit 21 Jun 2016 by Sherry Yang

Import programLSM6DS3_Demo

Demo for LSM6DS3

Last commit 20 Jun 2016 by Sherry Yang

However, I can not test it because I do not have this Sparfun board but when I check your spi.write

Spi.write

 spi.write(0x8F);

are you sure with 0x8F?

Best regards

J.

1) I already tried the Libary. But it is only for I2C. I2C is working well but i want to use SPI. 2) The Spi Write command should be sperated to 0x80 for reading and 0x0F for WHO_AM_i register. So you get, if you want to read the WHO_AM_I register, 0x8F.

posted by Maximilian Ogris 28 May 2019

Ah sorry, my mistake, but still exist another one with both interfaces https://os.mbed.com/teams/adamchuang/code/LSM6DS3/file/c19d384b2896/LSM6DS3.h/

posted by Jan Kamidra 29 May 2019