Configuring LIS3DH

[yohai]

Posted on February 20, 2014 at 08:31

I connected LIS3DH in the following way , but the device does'nt give the correct reading. 

        What is wrong with this configuration? Vin = 3.3V, SPI 4 wires. I configured the registers with the following string  at SPI: 0x60,0x77,0,0x10,0xC8,0,0 (command 0x60 , Reg1 0x77, Reg2 0, reg3 0x10, reg 4 0xC8, reg 5 & 6 0.) I can read this conficuration back and it's stored OK at the device. I read data by command 0xE8+6 bytes of zero But the OUT_XY&Z give me wrong values .  Eg 0xFE,0xA0,0x01,0xA0,0xFD,0x70 0r 0xFE,0x90,0x01,0x90,0xFD,0x40

[avieira]

Posted on February 20, 2014 at 13:19

Hello

Try to put CTRL_REG1 with 0x67 in order to enable the X-Y-Z Axis.

[yohai]

Posted on February 23, 2014 at 12:16

Thank you very much! Your advice helped.

Now the device is measuring. I have read the spec' again and as I understand the difference between ControlReg1 == 0x77 and ControlReg1 == 0x67 is ODR0 == 1 or 0. according to Table 26 it sets freq' to 400Hz or 200Hz. It looks that I am missing something in the spec'  (

Doc ID 17530 Rev 1 May 2010

)

or is there another register definition? Thanks again yohai.

[avieira]

Posted on February 24, 2014 at 10:49

Hi

Yes, the difference between CTRL_REG_1 as 0x67 or 0x77 is the ODR rate, 200Hz or 400Hz.Depending how the I2C is configured and implemented (assuming you are using I2C) it could be complicated to read the output values at a frequency of 400Hz.At this rates, it may be advisable to have the BDU bit (CTRL_REG_4) activated.