142 lines
4.0 KiB
C
142 lines
4.0 KiB
C
/****************************************************************************
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* apps/examples/termios/termios_main.c
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <stdio.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include <termios.h>
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* main
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****************************************************************************/
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int main(int argc, FAR char *argv[])
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{
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int fd;
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int ret;
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int error = OK;
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struct termios tio;
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printf("Termios example\n");
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fd = open("/dev/ttyS0", O_RDONLY);
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if (fd < 0)
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{
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error = errno;
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printf("Error opening serial: %d\n", error);
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}
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/* Fill the termios struct with the current values. */
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ret = tcgetattr(fd, &tio);
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if (ret < 0)
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{
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error = errno;
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printf("Error getting attributes: %d\n", error);
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}
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/* Configure a baud rate.
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* NuttX doesn't support different baud rates for RX and TX.
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* So, both cfisetospeed() and cfisetispeed() are overwritten
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* by cfsetspeed.
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*/
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ret = cfsetspeed(&tio, B57600);
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if (ret < 0)
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{
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error = errno;
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printf("Error setting baud rate: %d\n", error);
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}
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/* Configure 2 stop bits. */
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tio.c_cflag |= CSTOPB;
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/* Enable parity and configure odd parity. */
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tio.c_cflag |= PARENB | PARODD;
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/* Change the data size to 7 bits */
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tio.c_cflag &= ~CSIZE; /* Clean the bits */
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tio.c_cflag |= CS7; /* 7 bits */
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#ifdef CONFIG_EXAMPLES_TERMIOS_DIS_HW_FC
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/* Disable the HW flow control */
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tio.c_cflag &= ~CCTS_OFLOW; /* Output flow control */
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tio.c_cflag &= ~CRTS_IFLOW; /* Input flow control */
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printf("Disabled HW Flow Control\n");
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#endif
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printf("Please, reopen the terminal with the new attributes,"
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" otherwise you will have garbage or a stuck terminal.\n"
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"If you disabled HW flow control, try disconnecting RTS and CTS.\n"
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"You may try: picocom /dev/ttyUSB0 --baud 57600"
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" --parity o --databits 7 --stopbits 2\n\n");
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fflush(stdout); /* Clean stdout buffer */
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/* Wait to empty the hardware buffer, otherwise the above message
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* will not be seen because the following command will take effect
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* before the hardware buffer gets empty. A small delay is enough.
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*/
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sleep(1);
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/* Change the attributes now. */
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ret = tcsetattr(fd, TCSANOW, &tio);
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if (ret < 0)
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{
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error = errno;
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/* Print the error code in the loop because at this
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* moment the serial attributes already changed
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*/
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}
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close(fd);
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/* Now, we should reopen the terminal with the new
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* attributes to see if they took effect;
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*/
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while (1)
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{
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printf("If you can read this message, the changes took effect.\n"
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"Expected error code: 0. Current code: %d\n", error);
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sleep(1);
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}
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return 0;
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}
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