LCD Hang and garbage value problem interfaced with LPC2387

Discussion in 'Embedded Systems and Microcontrollers' started by udayan1987, Nov 1, 2014.

  1. udayan1987

    Thread Starter New Member

    Oct 7, 2014
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    HI, I am using LPC 2387 controller and interfaced GSM module, Ethernet, 8 relays to switch AC load, smoke detector, vibration sensor and three input switches in this i am facing some problems as i have seen this it shows unexpected values on LCD Display, so i check for noise spikes in power supply so i am getting it over their but after adding Filter and capacitors it still their even we have used transistor to switch relays....... please help me to solve this ........... i have used 16by 2 lcd. some times it shows proper characters on display but after some time it shows any random data. i have checked all the soldering points on PCB and i also have catch diode across relay.
     
  2. udayan1987

    Thread Starter New Member

    Oct 7, 2014
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    0
    hi i have just started to design embedded system based circuits its my first design that i am doing it on LPC 2387 Arm Controller. i want to built my demo board which will have LPC2387, GSM sim900, Ethernet, 8 Relays triggered with transistor, RS 232, I2C, and Display 16by 2 LCD and IO's. so i dont understand how to start. i have designed Clock Circuit and reset circuit. Mainly i have doubt with

    1> Power Section and Filtering
    2> IO section
    3> Different interfacing
     
  3. djsfantasi

    AAC Fanatic!

    Apr 11, 2010
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    Do you have suppression diodes across the relay coils? Like in the following diagram?
    [​IMG]
     
  4. udayan1987

    Thread Starter New Member

    Oct 7, 2014
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    ya we are having diode across relay
     
  5. udayan1987

    Thread Starter New Member

    Oct 7, 2014
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    here i have attach one pic showing how we are connecting relays to switch output or AC. Please any one can tell me is is right way to use it or do i need some changes. one more thing is in my mind that if i am not using any IO pin of LPC 2387 then what should i do Leave it as it is without connecting it neither with the VCC nor with the GND or should i add pull up or pull down resistor on that pin.
     
    Last edited: Nov 1, 2014
  6. ErnieM

    AAC Fanatic!

    Apr 24, 2011
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    How random? Are the bad characters always in the same place? Always the same bad characters? Or is it an occasiona changed character previosly written and just changed for no reason?

    It would probably be best if you publish the entire schematic all at once instead of little pieces.

    Some photos of the build may also help.
     
  7. udayan1987

    Thread Starter New Member

    Oct 7, 2014
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    Thank you all finally we solved our problem problem was in serial connector that was faulty.
     
  8. djsfantasi

    AAC Fanatic!

    Apr 11, 2010
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    Thanks for letting us know the final outcome!
     
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