Questions/Basic/16F628A


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  1. #1
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    Default Questions/Basic/16F628A

    I am building firmware for this pic to interface it with a Vector 2VXe compass module. The datasheet states the basic Datagram Structure to be

    Sync Flag
    0xAA
    Frame Type
    0xXX (example 0x01)
    Terminator
    0x00

    If I am using pbp and the shiftin(out) commands, how exatcly do I format the data? Do I send the bit representation of the hex (example: 170 for 0xAA), or could I simply shiftin(out) a variable that contains a string like "0xAA"?

    I have a rough draft that I threw up in a couple of days, and now I am going back to fix the areas that I needed more information on. Could I post my code? Its about 700 lines long.

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    One, more thing....How many bytes are in a word for this particular mcu. Since it's an 8bit mcu, its two bytes right?

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    tap tap tap... is this thing on? One more thing. Does anyone have any experience or code to share on how to convert a floating point number in basic? The output of the Vector compass is in IEEE 754 format, so I assume I have to convert this to a usable format in basic.

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    I've never used it so I can say how it works but there is code on ME Lebs website for performing floating point. I stay away from FP just for headache sake.

    And yes there are 2 bytes to a word.

    Bit is a Bit
    Byte is 8 Bits
    Word if 2 Bytes or 16 Bits

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    Quote Originally Posted by CocaColaKid
    I've never used it so I can say how it works but there is code on ME Lebs website for performing floating point. I stay away from FP just for headache sake.

    And yes there are 2 bytes to a word.

    Bit is a Bit
    Byte is 8 Bits
    Word if 2 Bytes or 16 Bits
    Yep came across that code. I will be picking it apart this evening to see if it can help me. Unfortunately, I cant stay away from floating point because this is what the v2xe outputs.

    Word is 2 bytes? I searched and read forever last night and the only definite conclusion I could reach was that it depends on the archietecture. Since my mcu is 8 bit, does this not mean 8 bit is the highest word the mcu can process?

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    Still working on it but here is what I got so far. I havent finished the menu system, nor have I figured a way to convert the floating point numbers coming from the V2Xe.
    Attached Files Attached Files

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    Quote Originally Posted by BertMan
    One, more thing....How many bytes are in a word for this particular mcu. Since it's an 8bit mcu, its two bytes right?
    Done some research on this and an 8 bit mcu means 8 bits to a word, which is the largest value the mcu can process. So, my next question is, how do I know when to set the variable to type word instead of byte when they both represent the same size - 8 bits?

    Am I posting in the wrong forum? Are my questions too stupid to answer? Am I on the right site? Or perhaps my questions are beyond the scope of the members here? Maybe I just dont have enough patience to wait for a response? Do I need to stfu and rtfm? Maybe someone could enlighten me before I go crazy talking to myself :-)
    Last edited by BertMan; - 21st September 2005 at 19:19.

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