LIS302DL not working

Discussion in 'The Projects Forum' started by alexpanrui, Feb 2, 2009.

  1. alexpanrui

    Thread Starter Active Member

    Feb 25, 2008
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    It was working few days a ago...this evening No matter what configuration I set, the output from any register is 0xFF..what's wrong? Is it defected? help....
     
  2. alexpanrui

    Thread Starter Active Member

    Feb 25, 2008
    32
    0
    anyone?thx..
     
  3. alexpanrui

    Thread Starter Active Member

    Feb 25, 2008
    32
    0
    plz help...anyone,plz!!!!!!!!!!!!!!!!!!!!!11
     
  4. alexpanrui

    Thread Starter Active Member

    Feb 25, 2008
    32
    0
    thanks for your reply...Ive browsed through some threads available over the net. I found that lots of people mentioned about putting pullups at the data lines and SCL/SCK, what does that for? for my case, i am using PIC16f877 to interface to the sensor, and i just directly hook the sensor to the pic...btw SPI is used for my case...the output high signal from pic is about 4.5v. is it too high for the sensor to handle? the sensor is powered at 3v for VDD and VDD_IO. anything wrong with this? thx
     
  5. alexpanrui

    Thread Starter Active Member

    Feb 25, 2008
    32
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    thank you so much. i should've noticed this...sigh.............
     
  6. alexpanrui

    Thread Starter Active Member

    Feb 25, 2008
    32
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    ---^^^^---------- device is this the right connection? thx
    10K |
    > 20K
    >
    |
    GND
     
  7. alexpanrui

    Thread Starter Active Member

    Feb 25, 2008
    32
    0
    sry, the system reformatted my texts... wat i mean is 10k resistor goes to the pic output and then to the device. and the 20k resistor is between 10k and the device.. am i right?
     
  8. alexpanrui

    Thread Starter Active Member

    Feb 25, 2008
    32
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    hi, alberto...now the voltage is stable at 3v...but i monitor the data sent to the pic from the sensor (i monitor it on the pc). its always 0. i checked pic datasheet. i found that pin RC4/SDI/SDA is Schmitt Trigger bufferred, which will recognize voltage approximately above 3.5v as input high. But the output high signal from the sensor is unable to reach that level now. and I think this is the reason I got output 0 from the sensor. how can I solve this problem?
     
    Last edited: Feb 5, 2009
  9. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Did you replace the LIS302DL since it stopped working, and after you used the 10k/20k resistive divider? If not, you need to - it's toasted.

    Are you using a regulated power supply for the LIS302DL and the PIC, or batteries?

    Inputs to the LIS302DL must not be lower than -0.3v, or higher than Vdd+0.3v. This is from page 14 of the datasheet:
    http://www.st.com/stonline/products/literature/ds/12726.pdf

    If you're running on batteries, you would be better off to use the same battery to power both the PIC and the LIS302DL. Make sure you use bypass capacitors on both the PIC and your sensor.
     
  10. alexpanrui

    Thread Starter Active Member

    Feb 25, 2008
    32
    0
    i forgot to mention i have 3 sensors. so ive already replaced the faulty sensor.sry abt that.i start this post is in case i dont burn the other two
     
  11. alexpanrui

    Thread Starter Active Member

    Feb 25, 2008
    32
    0
    problem solved...thank u alberto... the resistor value is too big...im using 330 ohm now
     
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