16F877A and Sensirion SHT21


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  1. #1
    Join Date
    Jan 2014
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    Default 16F877A and Sensirion SHT21

    Hi,

    does anyone here have a picbasic code for reading the SHT21 using 16F877A.

    i tried I2CREAD and I2CWRITE commands and it does not work.

  2. #2
    katelara's Avatar
    katelara Guest

    Default Re: 16F877A and Sensirion SHT21

    The first issue, obviously, is memory. There's no 16F or 18F PIC available with >256kB memory, I think the most memory you can get in the 8bit ones is 128kB - so you're going to need an external memory of some sort.

  3. #3
    Join Date
    Feb 2013
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    793

    Default Re: 16F877A and Sensirion SHT21

    I also want to use this sensor, but how it is related to available memory?

  4. #4
    Join Date
    Jan 2014
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    Default Re: 16F877A and Sensirion SHT21

    it worked fine now. My mistake was to use SHT21 in hold master mode.

    the built in I2CREAD and I2CWRITE on Picbasic works perfectly on SHT21 but in No-Hold Master Master mode only . It took me several days to make it work.

  5. #5
    Join Date
    Feb 2013
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    793

    Default Re: 16F877A and Sensirion SHT21

    Can you please share the code how to work with SHT21 ?

  6. #6
    Join Date
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    FLA
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    Default Re: 16F877A and Sensirion SHT21

    Maybe if we ask nicely? Please ....or at least point us in the right direction....

    Hold Master mode or No Hold Master
    mode. In the first case the SCL line is blocked (controlled
    by sensor) during measurement process while in the latter
    case the SCL line remains open for other communication
    while the sensor is processing the measurement.

    Quote Originally Posted by CuriousOne View Post
    Can you please share the code how to work with SHT21 ?

  7. #7
    Join Date
    Jun 2008
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    Varese , Italy
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    Default Re: 16F877A and Sensirion SHT21

    Could anyone share the code for reading the sht21 or the si7021 please ?
    Thanks
    Ambro

  8. #8
    Join Date
    Oct 2009
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    582

    Default Re: 16F877A and Sensirion SHT21

    If you don't need the precision of the SHT21, then use any of the DHT11, DHT21, DHT22, AM2302 sensors and the library file here http://www.picbasic.co.uk/forum/showthread.php?t=19975

  9. #9
    Join Date
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    Varese , Italy
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    Default Re: 16F877A and Sensirion SHT21

    thanks ,
    I do really need the si7021 .
    Ambro

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