problem with MAX232 output

Discussion in 'Embedded Systems and Microcontrollers' started by perzade, Jun 3, 2012.

  1. perzade

    Thread Starter New Member

    Jan 30, 2011
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    Using any one out of two line drivers of MAX232, I m having incorrect voltage at Rin pin (pin 13 for line driver 1 or pin 8 of line driver2).For input voltage of 5 volt at pins 9 & 10, I get -8.9v at pin 7 but in mv range at pin 8. I rechecked ckt connections & even used other IC but of no use. What could be the problem?
     
  2. t06afre

    AAC Fanatic!

    May 11, 2009
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    If you are sure the output is not shorted to GND. It could be a bad chip. I hvae fried some max 232 in my time
     
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  3. MrChips

    Moderator

    Oct 2, 2009
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    Your pin numbers don't match my MAX232. Can you post the part number and your circuit diagram?
     
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  4. praondevou

    AAC Fanatic!

    Jul 9, 2011
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    Yes, circuit diagram please. Pin 9 is not an input. This is why you don't get anything out of pin 8. Because that's the corresponding input for pin 9.
     
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  5. perzade

    Thread Starter New Member

    Jan 30, 2011
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    ya, actually I m only transmitting from uC AT89C51 to PC & that pair input & output voltages is fine. I thnk I should be able to receive data at PC
     
  6. ErnieM

    AAC Fanatic!

    Apr 24, 2011
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    Yah, post that schematic please. You seem to have some pins swapped.

    Also keep in mind that the TX of your device goes to the RX of your PC, and RX of your device goes to the TX of the PC.

    Seems simple but I swapped em first time I wired an SPI interface. :D
     
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