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RE: [Electronics_101] Re: DS1307 with an 8515/ Crystal problems

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  • Vijay Raju
    I have a bank of LEDs which count the seconds connected to the 8515. As long as the probe is there the LEDs count up and once the probe is removed the LEDs
    Message 1 of 7 , Jul 31, 2003
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      I have a bank of LEDs which count the seconds connected to the 8515. As long as the probe is there the LEDs count up and once the probe is removed the LEDs freeze, put the probe back and it starts again.

       

                           ,,,

                          (@-@)

              +==---o00----(_)----00o-----==+

              {                             |

              {        Thoughts from        |

              {         Vijay  Raju         |

              {                             |

              +==-------------------------==+

                         |__|__|

                          || ||

                         ooO Ooo

       

      -----Original Message-----
      From: manifold [mailto:manifold_1@...]
      Sent: Friday, August 01, 2003 4:32 AM
      To: Electronics_101@yahoogroups.com
      Subject: [Electronics_101] Re: DS1307 with an 8515/ Crystal problems

       

      Make sure it is the right kind of xtal. Though I am not sure if they
      have different cuts for the 32k watch xtal. These take forever to
      stabilize so make sure you are giving it enough time after power up.
      Check the data sheets again and see if there are any special
      requirements for the oscillator to work right. Check all the power
      requirements including if it must have a battery backup or not.  From
      the behavior you described, it sounds like you have the wrong XTAL in
      the circuit or stray capacitance.

      Make sure your layout is according to the data sheet. If the leads
      are too long it will not work.

      BTW, how can you tell that it stops oscillating when you remove your
      probe?


      --- In Electronics_101@yahoogroups.com, "Vijay Raju"
      <vijayxraju@s...> wrote:
      > Hi,

      > I have a DS1307 hooked up to an 8515 on pins PD4 (SDA) and PD5
      (SCL). I
      > am using the I2C code library in GCC written by Peter Fleury which I
      > found at http://jump.to/fleury. The I2C communication seems to work
      fine
      > I am able to write to the chip and read back from it reliably. But
      the
      > oscillator is not functioning. I have connected a 32.768 KHz
      crystal as
      > recommended in the data sheet to pins 1 and 2 of the DS1307. As
      long as
      > I have a DMM or a CRO hooked to pin 1, the oscillator works. The
      minute
      > I remove the CRO the oscillator stops. I tried putting a 22pF
      capacitor
      > across pin1 and ground but this didn't help. I have also tried
      changing
      > the crystal this doesn't help either. What could be causing this
      > problem?

      > Regards,

      >                      ,,,
      >                     (@-@)
      >         +==---o00----(_)----00o-----==+
      >         {                             |
      >         {        Thoughts from        |
      >         {         Vijay <mailto:vijayxraju@s...>   Raju
      > |
      >         {                             |
      >         +==-------------------------==+
      >                    |__|__|
      >                     || ||
      >                    ooO Ooo



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    • ghidera2000
      Two silly questions: 1) Do you have pullups on SDA and SCL? Not sure how a DMM could make up for a lack of pullups but hey, you never know. 2) Could it be you
      Message 2 of 7 , Aug 6 10:04 PM
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        Two silly questions:

        1) Do you have pullups on SDA and SCL? Not sure how a DMM could make
        up for a lack of pullups but hey, you never know.

        2) Could it be you simply have a bad power connection? Can you read
        the time from the DS1307? If it is actually powering down, it'll
        reset to 01/01/2000. Set the date, do your DMM trick, then check the
        date again. If the date has reset, check your power connections.

        --- In Electronics_101@yahoogroups.com, "Vijay Raju"
        <vijayxraju@s...> wrote:
        > I have a bank of LEDs which count the seconds connected to the
        8515. As
        > long as the probe is there the LEDs count up and once the probe is
        > removed the LEDs freeze, put the probe back and it starts again.
      • sanjay yadav
        Hi All, I wish to present a paper on subject digital protection of power systems in college. Please suggest me some websites where I can get relevant data.
        Message 3 of 7 , Aug 6 10:35 PM
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          Hi All,

          I wish to present a paper on subject "digital
          protection of power systems" in college.
          Please suggest me some websites where I can
          get relevant data.

          thanx in advance,
          Sanjay

          ________________________________________________________________________
          Send free SMS using the Yahoo! Messenger. Go to http://in.mobile.yahoo.com/new/pc/
        • Charles Douvier
          What are you trying to protect in the power supply? Ddo you have any outline? Like thermally? Compenating for component failure? Self-Shutdown? ... From:
          Message 4 of 7 , Aug 7 6:50 AM
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            What are you trying to protect in the power supply? Ddo you have any outline? Like thermally? Compenating for component failure? Self-Shutdown?
            -----Original Message-----
            From: sanjay yadav [mailto:sanjay_iddc@...]
            Sent: Wednesday, August 06, 2003 11:36 PM
            To: Electronics_101@yahoogroups.com
            Subject: [Electronics_101] Please suggest some good sites

            Hi All,

            I wish to present a paper on subject "digital
            protection of power systems" in college.
            Please suggest me some websites where I can
            get relevant data.

            thanx in advance,
            Sanjay

            ________________________________________________________________________
            Send free SMS using the Yahoo! Messenger. Go to http://in.mobile.yahoo.com/new/pc/


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          • manifold
            Do you know about google? http://www.iee.org/Publish/Books/Power/Po015zc.cfm ... ______________________________________________________________________ __ ...
            Message 5 of 7 , Aug 7 8:53 PM
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              Do you know about google?
              http://www.iee.org/Publish/Books/Power/Po015zc.cfm

              --- In Electronics_101@yahoogroups.com, sanjay yadav
              <sanjay_iddc@y...> wrote:
              > Hi All,
              >
              > I wish to present a paper on subject "digital
              > protection of power systems" in college.
              > Please suggest me some websites where I can
              > get relevant data.
              >
              > thanx in advance,
              > Sanjay
              >
              >
              ______________________________________________________________________
              __
              > Send free SMS using the Yahoo! Messenger. Go to
              http://in.mobile.yahoo.com/new/pc/
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