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49 lines
1.9 KiB
49 lines
1.9 KiB
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(1)
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int open_serial(const char *dev_name)
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This function opens a seirial device.It returns a descripter that you can use to access the COM port,for instance,"/dev/ttyAMA0".
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Parameters
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dev_name Pointer to a null-terminated string that specifies the name of the COM port to open.
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(2)
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int set_speed(int fd)
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This function sets the input and output baudrate of a COM port to 115200,and flushes both data received but not read, and data written but not transmitted.
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It returns success if any of the requested changes counld be successfully carried out.
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return value 0 indicates success.
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return value -1 indicates failure.
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Parameters
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fd Descripter of the COM port the property of which would be changed.
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(3)
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int set_serial_rowmode(int fd)
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This function sets the data bits of a COM port to 8,disables parity generation on output and parity checking for input ,and sets one stop bit.
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It sets timeout in deciseconds for non-canonical read to 128 and minimum number of characters for non-canonical read to 1,and echos input characters.
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return value 0 indicates success.
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return value -1 indicates failure.
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Parameters
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fd Descripter of the COM port the property of which would be changed.
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===============================================================
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Example Code
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The following example demonstrates the use of the read function.
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char buff[10];//Buffer for the data to read.
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int length = 1;//Length of the data to read.
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int ret = read(fd, buf,length);
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//the ret value indiates the count of data read.
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if(ret == length)
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{
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//It indicates that the the read operation is successfully carried out.
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}
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--------------------------------------------------------------
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The following example demonstrates the use of the write function.
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char buf[10] = "123456789";// Buffer containing the data to be transmitted to the COM port.
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write(fd,buf,10);//It sends 10 bytes to the the COM port.
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