RE: About energy-saving point of view, and the most optimal way to proceed in

trdop — Fri, 05 May 2017 08:34:26 GMT

Hi all,

Indeed from what it emerges, thank you for your good preconization ! I will do that.

Thanks David and Alex for your sample extract of code regarding your configuration of LIS2DH.

I tried to apply it strictly, but in order to really have a relevant result with regard to a shake (for example a flick in the desk).

I have to mix with a post example that I find on the forums of ST: community.st.com/.../37167-lis2dh-accelerometer-interrupts

To be concise here is the result of what I program on my LIS2:

extern LIS2DH12_Ret LIS2DH12_setToGeneratedSignalOnINT1asSoonAsShakeEventRecognisedMode() {

    LIS2DH12_Ret retVal = LIS2DH12_RET_OK;

    retVal |= writeRegister(LIS2DH_CTRL_REG1,       0x4F    /*_0x7F*/     );      // 79
    retVal |= writeRegister(LIS2DH_CTRL_REG2,       0x01    /*_0x00*/     );      // 1
    retVal |= writeRegister(LIS2DH_CTRL_REG3,       0x40    /*0x40*/      );      // 64
    retVal |= writeRegister(LIS2DH_CTRL_REG4,       0x00    /*_0x80*/     );      // 0
    retVal |= writeRegister(LIS2DH_CTRL_REG5,       0x00    /*_0x00*/     );      // 10
    retVal |= writeRegister(LIS2DH_CTRL_REG6,       0x00    /*_0x00*/     );      // 32

    retVal |= writeRegister(LIS2DH_INT1_CFG,        0xAA    /*_0x04*/     );      // 170
    retVal |= writeRegister(LIS2DH_INT1_THS,        0x02    /*_0x0F*/     );      // 2
    retVal |= writeRegister(LIS2DH_INT1_DURATION,   0x01    /*0x01*/      );      // 1

    return retVal;
}

RE: About energy-saving point of view, and the most optimal way to proceed in

Alex — Thu, 20 Apr 2017 08:31:56 GMT

As you suggested, the best way is to connect INT1 output of LIS2DH12 to nRF52 input. Program LIS2DH12 so that signal will be generated on INT1 as soon as shake event recognised by LIS2DH12. Program nRF52 input to wake CPU from deep sleep on level change on that input. We did the same on our product. Works fine. To save you time here is data we program to LIS2DH12 addr<-value: 0x20<-0x4F,0x21<-0x01,0x22<-0x40,0x23<-0x00,0x24<-0x0A,0x25<-0x20,0x30<-0xAA,0x32<-0x02,0x33<-0x01