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Options.c_cc = 1 /* Read a character and wait for 1*(1/10)s*/ Set waiting time and minimum receive character Modify the output mode to output raw data Options.c_cflag &=~CSIZE //Shield other flagsįprintf(stderr,"Unsupported data size/n") įprintf(stderr,"Unsupported stop bits/n")
SERIAL TERMINAL PROGRAM LINUX SERIAL
Modify the control mode so that input data can be read from serial port Modify the control mode to ensure that the program does not occupy the serial port Setting Serial Port Input and Output Baud Ratesįor ( i= 0 i < sizeof(speed_arr) / sizeof(int) i++) If the call is successful, the return value of the function is 0, and if the call fails, the return value of the function is 1. This function can also test whether the configuration is correct, whether the serial port is available, etc. * tcgetattr (fd, & options) obtains the parameters related to the FD pointing object and saves them in options. Int UART0_Set(int fd,int speed,int flow_ctrl,int databits,int stopbits,int parity) * Stop bits Stop bits Stop bits Stop bits Stop bits Stop bits Stop bits Stop bits Stop bits Stop bits Stop bits Stop bits Stop bits Stop bits Stop bits Stop bits Stop bits * Entry parameters: fd Serial Port File Descriptor * Function: Set up serial data bits, stop bits and validation bits When setting data bits, CSIZE must be used as bit shielding.Ĥ > What methods are used to mark the beginning and end of data transmission in data flow control?ĥ > After setting baud rate, data flow control, data bits, check bits, stop bits, stop bits, minimum waiting time and minimum receiving characters are set.Ħ > After the configuration is completed, the configuration is activated through the tcsetattr() function. CS5, CS6, CS7 and CS8 correspond to 5, 6, 7 and 8 data bits. In general, the input and output baud rates are equal.ģ > Setting data bits can be achieved by modifying c_flag in termios mechanism. Tcgettattr (fd, & options) obtains the pointer of serial port to termios structure.Ģ > The input/output baud rate of serial port is set by cfsetispeed function and cfsetospeed function. number of data bits, stop bits, check bits)ġ > termios structure is used when setting serial port parameters, so the function must be used first. The serial initialization module consists of those parts:Ģ > Format the frame (i.e. number of data bits, stop bits, check bits, data flow control) need to be set.Ģ. Serial port baud rate, data flow control, frame format (i.e. Serial port initialization in linux is the same as the previous serial port initialization. Determine whether the state of the serial port is blocked or not.ġ. * Export parameter: * Correct return to 1, error return to 0
SERIAL TERMINAL PROGRAM LINUX PASSWORD
* Entry parameter: fd File descriptor port: serial password (ttyS0,ttyS1,ttyS2) * Function: Open the serial port and return the description of the serial device file Opening the serial module has that and some components.ġ > Call the open() function to open the serial port and get the device file descriptor of the serial portĢ > Obtain the state of serial port and judge whether it is blocked or notģ> test Is the open file descriptor a terminal device? O_NDELAY: Indicates that you do not care about the state of the DCD signa l line (whether the other end of the port is activated or stopped).ģ. If this flag is not used, a task input (eg: keyboard stop signal, etc.) will affect the process. O_NOCTTY: This means that a terminal device is opened and the program will not become the control terminal of the port. For the open operation of the serial port, the O_NOCTTY parameter must be used. Call the open() function to replace the serial device.
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In Linxu, serial devices are accessed through serial terminal device files, that is, by accessing / dev/ttyS0,/dev/ttyS1,/dev/ttyS2.Ģ. Since the serial port is in the linux It is regarded as a file, so it should be opened before it is operated.ġ. Linux The following serial port programming and those components