UART vs software RS232


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  1. #1

    Default UART vs software RS232

    I must be missing something but isn't RS232....RS232?

    If it's an RS232 data stream, 5v logic 1 and 0v logic 0, there wouldn't be any difference between a UART and software RS232?

    I have 2 PICS that work fine together with software RS232, one transmits...the other is a receiver.

    But, no matter what I try I can't get a wireless link to work.....modules I know are configured right. (xstream modules).

    Only thing in the maxstream documentation is that the serial data interface required is listed as CMOS UART.

    Maybe I need to pullup both PIC pins or something? (I think I tried that though).

    THANKS.

  2. #2
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    If the system works with a wire between the two microprocessors then you can say the folowing:
    The transmitter does not transmit.
    The receiver does not recieve.
    Both don't work.
    The transmitter or the receiver or both units change the pulse into something else or even invert it.
    I should say: Take an oscilloscope and do some measurements.
    This is the quickest way to see and solve you problem.

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    So if the modules are asking for CMOS UART in the data sheet, then you don't see a problem with a direct connection from the PIC pins using software RS232?

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    The difference may be if signals are inverted or not.
    If using SEROUT try HSEROUT.

    Norm

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    I'll try inverting -- that option may be on the module in configuration -- like I say the hardwired connection is fine.

    Pardon my lack of knowledge on the matter but what exactly is the difference between
    software serin and serout, hserin etc and the UART?

    I know the good thing about the UART is that it can run in the background but other than that, what are the differences?

    Thanks kindly.

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    The USART is hardware, is faster (115.2k baud), has a buffer but is not capable of inverting to eliminate an RS232 driver.

    If using SEROUT try inverting or non inverting as per the table in PBP help.

    Which command for RS232 are you using?

    Norm

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