serial port??

This is a discussion on serial port?? within the Windows Programming forums, part of the Platform Specific Boards category; Hi: If I use COM1(hCom1) write data and COM2(hCom2) to receive data, so: Code: #define input_Buffer 2 //for hCom2 input ...

  1. #1
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    serial port??

    Hi:

    If I use COM1(hCom1) write data and COM2(hCom2) to receive data, so:

    Code:
    #define input_Buffer 2 //for hCom2 input buffer
    //#define output_Buffer 10
    
    char valRead[20]={0};
    
    SetupComm(hCom2, input_Buffer, output_Buffer)
    
    /* hCom2 only can have only 2 bytes receved at time, right??*/
    
    /*assume that there are 100 bytes already in hCom1 and I use one cable to connect COM1 and COM2 with each other*/
    
    /*now I start reading from COM2*/
    
    ReadFile(hCom2, &valRead, 10, &dwRead, NULL);
    the problem now is:

    I think there must be only 2 bytes in buffer valRead cause the maximum input buffer in hCom2 is 2 bytes only. But always there are 10 bytes in valRead, Why??? and it still is not working with

    dcb.ByteSize= 2;

    .
    Thanks for help.
    Don't laugh at me,I am just a SuperNewbie.

  2. #2
    Registered User Codeplug's Avatar
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    4,647
    Don't call SetupComm(). The device driver will use setup appropriate default values for you.

    You don't want to limit the receive buffer for your port. Just read 2 bytes at a time if that's what you're trying to accomplish.

    Use the SFile object I showed you in your other thread, or use is as a reference for Win32 serial communications.

    gg

  3. #3
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