// 1. Open the serial port (Replace /dev/ttyUSB0 with your port) serial_port = open( "/dev/ttyUSB0" , O_RDWR | O_NOCTTY); (serial_port < ) { printf( "Error %i from open: %s\n" , errno, strerror(errno)); // 2. Configure the port using the termios struct termios tty; (tcgetattr(serial_port, &tty) != ) { printf( "Error %i from tcgetattr: %s\n" , errno, strerror(errno)); // Set Baud Rate (9600) cfsetispeed(&tty, B9600); cfsetospeed(&tty, B9600);
if (tcsetattr(fd, TCSANOW, &tty) != 0) perror("tcsetattr"); close(fd); return -1; serial port c example
#include #include int main() GENERIC_WRITE, 0, NULL, OPEN_EXISTING, 0, NULL); if (hSerial == INVALID_HANDLE_VALUE) printf("Error opening port\n"); return 1; // 2. Configure settings DCB dcbSerialParams = 0; dcbSerialParams.DCBlength = sizeof(dcbSerialParams); GetCommState(hSerial, &dcbSerialParams); dcbSerialParams.BaudRate = CBR_9600; dcbSerialParams.ByteSize = 8; dcbSerialParams.StopBits = ONESTOPBIT; dcbSerialParams.Parity = NOPARITY; SetCommState(hSerial, &dcbSerialParams); // 3. Write data char bytes_to_send[] = "Hello Windows"; DWORD bytes_written; WriteFile(hSerial, bytes_to_send, strlen(bytes_to_send), &bytes_written, NULL); CloseHandle(hSerial); return 0; Use code with caution. Copied to clipboard Write data char bytes_to_send[] = "Hello Windows"; DWORD
Treat the serial port as a file (e.g., /dev/ttyUSB0 ). | | c_iflag | Input flags: handling of
| Field | Purpose | |--------------|------------------------------------------------| | c_cflag | Control flags: baud rate, parity, stop bits, CS8/CS7, hardware flow control. | | c_iflag | Input flags: handling of BREAK, parity errors, flow control (software). | | c_oflag | Output flags: output processing (usually set to 0 for raw data). | | c_lflag | Local flags: echoing, signals, canonical mode. | | c_cc[NCCS] | Control characters: VMIN, VTIME for read timeouts. | | c_ispeed | Input baud rate (separate or via cfsetispeed). | | c_ospeed | Output baud rate. |
tty.c_cflag |= (CLOCAL | CREAD); /* ignore modem controls */ tty.c_cflag &= ~CSIZE; tty.c_cflag |= CS8; /* 8-bit characters */ tty.c_cflag &= ~PARENB; /* no parity */ tty.c_cflag &= ~CSTOPB; /* only need 1 stop bit */ tty.c_cflag &= ~CRTSCTS; /* no hardware flowcontrol */