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  1. #1
    Regular Contributor
    Join Date
    Jul 2007
    Posts
    161

    Reading from comm port

    I need to read data from GPS receiver.
    1) GPS receiver writes data every second. But i don't need such frequent updates. So if I will read it every second, it will shorten battery-life.
    2) I want to choose between two possible ways of reading data in background.
    a) CPeriodic object reads data from GPS receiver every second, and if data string is a complete structure (symbols $ [something] \r\n is there) - parse it and put it into proper class which needs gps location.
    b) CActive (but I am not sure, is it just simple thread?) - run reading process in background, and I should be able to terminate it even if it is waiting data from receiver (if receiver suddenly was turned off).
    3) I can also imagine my application connecting, reading and disconnecting from receiver every time i need data, but such implementation scares me

    Could anyone help me to
    1) choose the way of reading data
    2) to understand how CActive works (tiny example will be great!)
    Thanks
    P.S
    Symbian 6.1 & 8.0a

  2. #2
    Super Contributor
    Join Date
    Oct 2005
    Posts
    739

    Re: Reading from comm port

    Hi,

    I think you are connecting to the gps receiver through bluetooth. So you have established a connection to the gps device. It will write to your blutooth socket in every seconds. Then its up to you to read from that socket or not.

    About second question. You just search on google using "active object symbian" as key word.

    I am here providing you some examples

    http://www.forum.nokia.com/info/sw.n...0b_en.zip.html
    http://newlc.com/Symbian-Active-Object-Framework-A.html
    http://wiki.forum.nokia.com/index.php/Active_object
    http://www.forum.nokia.com/info/sw.n..._v1_1.zip.html

    regards,
    Peter

  3. #3
    Regular Contributor
    Join Date
    Jul 2007
    Posts
    161

    Re: Reading from comm port

    Then its up to you to read from that socket or not.
    And what if system internal buffer overflows? I will get wrong data?
    The other catch is that while moving, gps coordinates from buffer remains old. So this way of reading data is not acceptable.
    About second question.
    Can you explain me what exactly means "active object"? I just can not understand the purpose of it.

    And, which of the following ways of reading data is better?

    Thank you for your answer.

  4. #4
    Super Contributor
    Join Date
    Oct 2005
    Posts
    739

    Re: Reading from comm port

    Hi,

    One thing i can suggest to you is to read from socket on every second and process it on the intervals as you want.

    And on active object this article on newlc will explain to you more cleary than me.
    http://newlc.com/ActiveObjects.html

    And then you can go through the links i have already provided to you or read any books related to symbian.

    I think for reading its better to maintain the connection with gps receiver without breaking it.

    Regards,
    Peter

  5. #5
    Regular Contributor
    Join Date
    Jul 2007
    Posts
    161

    Re: Reading from comm port

    Thank you very much

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