ICANON Enable canonical mode. print all current settings in human-readable form. One common reason to modify termios settings is to read a password without echoing characters. ) Specify an initial speed instead of the hardware default. You can find the rest described in the. kernel. This sort of thing is managed by the readline library whose behavior can be controlled via ~/. clocal (-clocal)The default settings for the UART interface are 57600 bps, 8 bits, no parity, 1 Stop bit, no flow control. You will need to set up the overall /etc/ppp/options with the common options for all dial up ports. CRTSCTS (not in POSIX) Enable RTS/CTS (hardware) flow control. DTR - Data Terminal Ready. Print or change terminal characteristics. c_lflag 的. Each section has a given name which will be used when using the configuration FIFO (normaly /var/run/l2tp-control). uart 通信のテストをする c のプログラムです。. The termio structure in the termio. When using the 2020. When any of the. xonxoff: A Boolean indicating whether to use software flow control (XON/XOFF signals). Currently, I'm testing flow control between 2 RS485 UART Port (Just connect Rx and RX, Tx and Tx, DTS/CTS is not connected). After that, CTS/RTS became effective. Disable console output on UART1 (ttyFIQ0) I have a Teensy microcontroller wired to UART1, so I want to disable console output on /dev/ttyFIQ0. Configured minicom to use hardware flow control (Ctl A-O to open minicom serial port setup menu, and F to enable hardware flow control). From info uucp, hardware flow control is on by default. – user2430607. PARENB can be used in the following way:The program output is as follows. Today that sort of installation is less common, which is good news for many people interested in operating this way. 2、 Uart 設定為 RTSCTS 下. PPP uses a number of files to connect and set up a PPP connection. Some did solve it by using the command "stty --file=/dev/ttyUSB0 crtscts -hupcl", and are pretending they have to send the command from the python script, in order to have the serial port working. h and in asm/termbits. Echo command hangs when writing to serial device. 1. In this case, using XON/XOFF flow control is aCRTSCTS on, CRTSXOFF on. Whenever the UART finds a 0x0A in the datastream it adds 0x0D with it and transmitting. hi, i’m new to QNX-rtp so bear with me for second. Read more about it here. i have some test code that runs on solaris and talks back and forth with an external controller via the serial port. 0. Saved searches Use saved searches to filter your results more quickly This assumes that sizeof (int) == 4 is true, adjust for other sizes as needed, the problem remains. From: Pavel Krasavin <pkrasavin@imaqliq. A "modem disconnect" apparently involves toggling the RTS line, because once that flag is disabled, the behavior goes away regardless of the CRTSCTS flag setting. 6. You have sent him a patch that has triggered this response. #4193. I use Terminator, but have also tried this in Terminal and get the same issue. It just hangs there. Print the PID when detaching. 05727363 VAT No. 0. > > > Replaced magic numbers used in the CRTSCTS flag code with symbolic > > names > > > from the chip specification. There are multiple ways of doing things because there were never any protocols built into the standards. on Dec 1, 2018. shkolnyy@xxxxxxxxx> > > > > This patch does not even compile. RTS is an output from the UART IP block so it must be routed to a CTS pin. Re: How to enable CTS RTS for Raspberry Pi 3 b+ UART. c_cflag &= ~(CSIZE | CSTOPB | PARENB | CRTSCTS. But I have found, that: * even if flow control is switched off, serial_core. May 21, 2015 at 15:21. Let's assume that I run a program which reads/writes to a serial port (/dev/ttyS0). tty. microcom -s 115200 /dev/ttyPS1. LANG=en_US. Some serial ports (such as Macintosh serial. After that, CTS/RTS became effective. -a, --all. PARODD is defined in header termios. `ixon' Enable XON/XOFF flow control (that is, `CTRL-S'/`CTRL-Q'). 14 (but can move to 4. > CRTSCTS constant will be defined. Sign up for free to join this conversation on GitHub . The output of this command, shown in Example 4. Teams. The embedded system will be 10. */ Baud: 9600, Char Bits: 8, Parity: NONE, Stop Bits: 2, RTS: ON, Flow Control: ON. microcom -s 115200 /dev/ttyPS1. • HW flow control enable with the crtscts option • The scripts for connect and disconnect • Other options depending on usage . The xl2tpd. -F, --file = DEVICE. However most of them have an infra-red interface and this tutorial describes how you can read it using a. Serial-HOWTO 의 7 장을 참조할 것. org, neil. 不會出現任何kernel panic，但是無法作loopback. > > > > > > Signed-off-by: Konstantin Shkolnyy <konstantin. One can use the TIOCMGET ioctl () to check the pin state, but then we need to send one byte at a time, which makes it. So Linux should be adapted to the standard, since we cannot adapt the standard to Linux. org Cc: <stable@vger. Then, CTS/RTS was not effective, and I have been worried for a long time. -g, --save. When you try to write to the UART output buffer it, probably, is full and application temporarily stops running and waits until some buffer space becomes available. ( Prolific PL-2303 HXD USB to RS-232 Serial Adaptor. Maybe it is time to update it? The text was updated successfully, but these errors were encountered:Hello Pavel, On Thu, Oct 12, 2023 at 10:23:30AM +0000, [email protected]. 0. i test with 2 method. # stty -a speed 38400 baud; rows 59; columns 208; line = 0; intr = ^C;QNX Momentics IDE User's Guide. txt 5 sudo shutdown -r now 6 sudo vim ~/boot/cmdline. Example 2: UART1 in DCE mode. 7 of Serial-HOWTO) CS8 : 8n1 (8bit,no parity,1 stopbit) CLOCAL : local connection, no modem contol CREAD : enable receiving characters */ newtio. RTS and CTS are not necessary. 1 Answer. 209 compatible = "xlnx,ps7-uart-1. Program Examples. $ stty 19200 cs8 -parenb crtscts -echo -F /dev/ttyS0. Many devices from personal computers to mobile devices make use of. com> Signed-off-by: Johan Hovold <[email protected] : output hardware flow control (only used if the cable has all necessary lines. 1 1 asked May 4, 2015 at 16:17 eliba 140 10 Add a comment 1 Answer Sorted by: 3 The problem was the -D_XOPEN_SOURCE=600 part of the gcc command. 2. 855641] ttyTHS ttyTHS0: 1 input overrun(s)crtscts: A Boolean indicating whether to use hardware flow control (RTS/CTS signals). Linux 序列埠程式設計. -g, --save. We can acquire some information by "stty -F /dev/ttyS0 -a ". this works fine. py:368it works good, good version of the controller, good FBuffer Length, When i read the buffer, the file begin by the correct magic word (0xFF 0xD8) but doesn't end with the correct one (0xFF 0xD9) which is strange because the file size it coherent with the annouced FBuffer size. Hi, I would like to use modem control signals (RTS/CTS) in my ZYNQ MIO peripherals, but I'm not sure about how to enable these features in my embedded design. 0. log proxyarp connect-delay 5000 refuse-pap refuse-chap refuse-mschap require-mschap-v2 #Windows连接必须设置. Read or write serial ports. xl2tpd of this project. el7 How reproducible: Connect to the server using L2TP. c","contentType":"file. Add a crtscts flag to keep track of the hardware flow-control setting and use it to suppress any request to change RTS when auto-RTS is enabled. sudo raspi-config. 4. sudo cat /dev/ttyUSBPort1. CRTSCTS : 하드웨어 흐름 제어. -F, -. Note that RTS+CTS almost spells: crtscts and. Hi, I'm trying to use RTS/CTS flow control with CP2102N / CP2104 devices on Mac OS. PDF version of Guide #3 - Claim for proceedings previously initiated before CRT. 要修改数据位可以通过修改termios结构体. It is only available for those Unix versions that support POSIX termios style tty I/O control configured during installation. org Cc: Greg Kroah-Hartman <gregkh@linuxfoundation. We are using GPIO 8/9/10/11 for UART4 incl. armstrong; +Cc: stable The patch below does not apply to the 5. 128 as the client) to the main server (192. The microcontroller responds to commands sent from the linux machine. When you try to write to the UART output buffer it, probably, is full and application temporarily stops running and waits until some buffer space becomes available. PARENB is defined in header termios. com>, Neil Armstrong <neil. Those boards are based on chips FT232RL CH340G CP2102 and others. display this help and exit. 460800 bps) or write into UART1 with higher baud-rate, read() from UART2 with lower baud-rate, FIFO (currently is 64byte) will be overflow as same as kernel send some notification. But /dev/ttyS* ports are full-duplex, with CRTSCTS or without, > so they don't use such handshaking. Then, CTS/RTS was not effective, and I have been worried for a long time. Serial Devices and the login: Prompt. From: <[email protected]. h The question >> is what is the correct state of affairs? >> 1) the manpage should say bits/termios. Passwords. sample. If this was allowed, your foreground shell and background task would race to read whatever you are typing, with each getting ~50% of the typed characters. RTS will be asserted except when the kernel input buffer is full. 4. HARDWARE The uart driver supports the following classes of UARTs: o NS8250: standard hardware based on the 8250, 16450, 16550, 16650, 16750 or the. After googleing a while, I found other people having the same issue. The UART operations are controlled by the configuration and mode registers. ICANON Enable canonical mode. 1. 2. o. 0. It's possible to setup a serial port communication using hardware flow control with the RTS/CTS pins (CRTSCTS flag for tcsetattr), but there is no way to use the DTR/DSR pins for flow control in a reliable and efficient way. This option is not implemented on Windows. Enter another number: Status: -1. 0. This option is not implemented on Windows. 147 win 10 64bit Build Tool: Vite Reproduction Related Component All Reproduction Link Link Steps to reproduce 不知道是volar的问题还. For example (the usual): to highlight a word/sentence: Shift + arrow key. 0037688F-00258A46. Sometime delete works as backspace. armstrong; +Cc: stable The patch below does not apply to the 4. -a, --all. The device. -F, --file = DEVICE. If the CNEW_RTSCTS or CRTSCTS. This enables the special characters EOF, EOL, EOL2, ERASE, KILL, LNEXT, REPRINT, STATUS, and WERASE, and buffers by lines. microcom -s 115200 /dev/ttyPS1. 모뎀 제어를 하지 않는다. before i get into the details (and show you the code) i have to advise you that i’m a mechanical engineer and thus. h instead of termios. Then without exiting the communications program (such. tty. Yesterday, after enabling the FCM of 0xFF000024 directly with the devmem command, stty -F /dev/ttyPS1 crtscts. The termios structure Many of the functions described here have a termios_p argument that is a pointer to a termios structure. Example of this issue when I attempt to output command history: albert@t450:/$ history 1 sudo rasp-config 2 sudo raspi-config 3 sudo nano /boot/cmdline. One common reason to modify termios settings is to read a password without echoing characters. 1) Does the qemu init all pci-serial port crtscts or raw? For example, I make the qemu configure with 4 pci-serial port. The machine has a small input buffer and uses hardware flow control to signal when it has completed a command and can receive a new one. 4. I have tried to set the correct serial settings using. The stty command has a crtscts flag that enables hardware handshaking on a device; you'll need to use this. I am using UART1 to transmit file. h> ). We'll cover the most important of these in a moment. 3. If a calling program is identified as requiring POSIX compatibility, the termios structure. The modem control lines TIOCM_CAR, TIOCM_CTS, TIOCM_RTS, TIOCM_DSR and TIOCM_DTR are provided for the serial ports, although the TIOCMGET ioctl() call will not return the state of the TIOCM_RTS or. 29%” and some “RxData DMA copy to tty layer failed”. 之後的部分，如讀寫則與一般網路. CRTSCTS is a 10 bits all 0 bit mask to turn off flo w control. CREAD : 문자 수신을 가능하게 한다. When i try to send any data through it with echo 'hello' > /dev/ttyS0, following happens: No data is recieved by the other side; oscilloscope shows no data is being sent. Based on the transmission modes, the serial communication can be classified as below: 1. 0. Ie, chat is not getting OK. The low level driver is also responsible for handling interrupts for the port, and providing any console support. Enabling this when it should be disabled can result in your serial port receiving no data, as the sender will buffer it indefinitely, waiting for you to be “ready”. 2 Crux. x release version of PetaLinux, the Linux AXI UART Lite driver kernel panics with loopback mode. This is basically 8N1, byte-at-a-time, with the TTY doing the minimal amount of futzing about with the data. hup -hup; speed nnnnSaved searches Use saved searches to filter your results more quickly>> CRTSCTS constant will be defined. stty -F /dev/ttyPS1 crtscts. Otherwise your code seems to function as expected on an ordinary serial port. Leaving CTS unconnected with flow control enabled, means DTE (AKA PC) cannot send data to DCE (slave device). first with “ GitHub - cbrake/linux-serial-test: Linux Serial Test Application ” enable rtscts control uart can transmit but no voltage change on rts and cts pin. ; The Pi shares the serial port with bluetooth. 1:192. 使用硬件流量控制（即 RTS/CTS）来控制串行端口上的数据流。如果未提供 crtscts、nocrtscts、cdtrcts 或 nocdtrcts 选项，则串行端口的硬件流量控制设置将保留不变。某些串行端口缺少真正的 RTS 输出，因此使用此模式来实施单向流量控制。 I have not been able to dig deep enough into this problem but I got around the issue by disabling crtscts in the patching tool and forcing auto rts/cts to be enabled for line 0. It's definition (from linux/termios. But then we are back to my original problem, how to autorun this without knowing if my device (/dev/ttyMarantz) exists or not? As before, it would be nice if socat were run by the udev rule, when the port is set up, but. The only thing I can think is. However, as you have pointed out, when the screen command is executed, the echo attribute of the selected serial port (in this case /dev/ttyS0) reverts to. Already have an account? Sign in to comment. You should very probably make the buffer unsigned char instead. Print or change terminal characteristics. all: uart_test. sudo stty -F /dev/ttyS0 -a. The termios structure Many of the functions. for input: when a input is recieved over the serial , the signal_handler_IO is called, which in turn sets the wait_flag to FALSE , so that the main loop reads the input from serial . ^M for enter): Shell working. Even serial ports/buses may be clocked considerably at quicker rate than the parallel ports/buses and can accomplish a higher. 今回は、ioctl()の第2,第3引数の正体とioctlの使い方について説明します。 まずはioctl()の引数について。crtscts (不属于 posix) 启用 rts/cts (硬件) 流控制。 c_lflag 标志常量： isig 当接受到字符 intr, quit, susp, 或 dsusp 时，产生相应的信号。 icanon 启用标准模式 (canonical mode)。允许使用特殊字符 eof, eol, eol2, erase, kill, lnext, reprint, status, 和 werase，以及按. Raspberry Pi で、TxD と RxD を短絡させてテストしました。. The UART may not be configured to use them. Uses the state of CTS signal to do outbound flow control and RTS signal to do inbound flow control. print all current settings in a stty-readable form. CTS - Clear To Send. it is used and works * add missing flow control pin configurations * change definition of MDMBUF to show it is an alias of CCAR_OFLOW * remove MDMBUF text in line with other flow control pinsSep 2 09:01:49 centos pppd[18018]: In file /etc/ppp/options. (시리얼 케이블이 모든 핀에 연결되어 있는 경우만 사용하도록 한다. 4 tty CRTSCTS option failure. Dmitry edited projects, added VyOS 1. 5, gives you the status of all flags for that device; a flag shown with a preceding minus, as in -crtscts, means that the flag has been turned off. (시리얼 케이블이 모든 핀에 연결되어 있는 경우만 사용하도록 한다. PC ( usually, DTE device): PC_UART_CTS ----INPUT; PC_UART_RTS---OUTPUT. I have tried to do echo /dev/ttyS0 but no output comes out. Linux The following serial port programming and those components 1. Examples. $ vi / etc / ppp / options _____ auth crtscts lock hide-password modem mru 296 mtu 296 lcp-echo-interval 30 lcp-echo-failure 4 noipx persist asyncmap 0xa0000 mru 1500 refuse-chap ipcp-max-failure 30 logfile / home / root / ppp In my case we use the PAP authentication file (may vary depending on Network Provider). xl2tpd (前略) #crtscts (中略) #lock (中略 末尾に追加) name xl2tpd refuse-pap refuse-chap refuse-mschap require-mschap-v2 persist logfile /var/log. Advantages of Serial Communication over Parallel Communication. There is a misconception that the serial ports/buses are slower than parallel ports/buses as the transmission of data is only a bit per unit of time. 3 in your dmesg output, it's probably the Intel AMT/MEI serial-over-LAN management. gitignore","path. o cc -o uart_test uart_test. c_cflag &= ~(CSIZE | CSTOPB | PARENB | CRTSCTS Previous Next. Get to know Eclipse; What's new in the IDE? Starting the IDE; Preparing your target; Creating a target connection crtscts -crtscts: Enable (disable RTS/CTS flow control. How are these two escape sequences usually handled in C?1. When sending commands, I can see that the device is responding with "invalid_parameter" by monitoring the port with. Output of stty -a Command. 이는 이 포트에 현재 rts/cts 플로우컨트롤이 사용된다는 뜻이다. The Arduino board is a prototyping and development platform. 2 Apr 22 2021 - 23:19:25. Question 1. 1、getopt_long 函数解析命令行参数，argc、argv是调用main函数时传入的参数。. I did not know how it happened and also how to fix the problem. I can't get this working out of the box. I've looked through the Arduino's Serial software websites, but none of them seemed to have a clear explanation or just no explanation at all how to program the serial communication. console to ttyAMA3, but I still get console output on UART1 during the boot sequence, and also all dmesg output still goes there. 1) Does the qemu init all pci-serial port crtscts or raw? For example, I make the qemu configure with 4 pci-serial port. From the command line, you'd use the (horribly confusing) stty command: Code: Select all. 2. A break condition can be sent on the serial link by using the TCSBRK. To do this, you want to turn off local echo while reading the password. This tutorial shows you how to use HUPCL. My goal is to analyze / modify the project completed by the staff. 説明. 2. For theoretical information on L2TP you can visit its Wiki. Some ISPs use L2TP to tunnel user sessions from dial-in servers (modem banks, ADSL DSLAMs) to back-end PPP servers. PC ( usually, DTE device): PC_UART_CTS ----INPUT; PC_UART_RTS---OUTPUT. Slow PPP link (tried asyncmap 0 and crtscts) 3. c_lflag flag constants: ISIG When any of the characters INTR, QUIT, SUSP, or DSUSP are received, generate the corresponding signal. We can acquire some information by "stty -F /dev/ttyS0 -a ". 11 2. Q&A for work. txt 7 cd /. Would anyone be able to help me with this?+1. Some versions of UNIX support hardware flow control using the CTS (Clear To Send) and RTS (Request To Send) signal lines. 1. As root, aptitude works correctly. All in Ubuntu Server 18, CC2531 works well in that environment. Check the specific port driver manual page to see if hardware flow control is supported on the port you are using. crtscts. 04. Configuration -> Windows -> Translation -> Remote character set : UTF-8. This patch was tested with success with a serial printer configured with a small buffer. From: <[email protected] tree Date: Wed, 22 Nov 2023. Passwords. Those pins are now connected, and communication is still unreliable at 4Mbaud, and still crashes above that speed. 28. or this: sudo screen /dev/ttyS0 115200,cs8,-parenb,-cstopb,inlcr,onlret,echo. CRTSCTS (not in POSIX) Enable RTS/CTS (hardware) flow control. 8. Here is some environment information: $ gcc --version $ gcc (Ubuntu 4. Gernerally speaking, before you connect one device to the other, you only need to confirm CTS & RTS directions of UART for 2 devices. stty -F /dev/ttySX crtscts (modify the /dev/ttySX to match your device). Facing similar issue. CRTS. 1113536 Company No. 16. Input modes. 1) Does the qemu init all pci-serial port crtscts or raw? For example, I make the qemu configure with 4 pci-serial port. The persist option will keep pppd alive in case of a disconnect or when it can't connect in the first place. Without this definition in the syscall package. Avoid repeating the same code for rs485 twice. 接著透過 file descriptor（檔案描述子）設定序列埠。. Your code should look like this: struct termios ts, ots; One structure keeps the original termios settings so that you can restore them. stty -f /dev/ttyu0. h. 4. CRTSCTS return termios. The microcontroller responds to commands sent from the linux machine. 2. CRTSCTS : 하드웨어 흐름 제어. c:38: error: `CRTSCTS' undeclared (first use in this function) > > CRTSCTS is defined in bits/termios. but result same as method one. The -bg /dev/ttyS* argument in the last command will print a neatly formatted summary of the hardware configuration of all active serial devices. stty -F /dev/ttyPS1 crtscts. stty sane. Which is a XY question and most probably is not what [he] really wants - to implement reading from the file descriptor in a separate thread with buffering (i. The state of the FIFOs, modem signals, and other controller functions are read using the status, interrupt Linux C 配置串口. UART adding 0x0d with 0x0a in the datastream. 我们操作串口跟操作文件一样，也是调用 open () 函数来打开串口，. (CRTs are fast enough to not need flow control). If neither the crtscts, the nocrtscts, the cdtrcts nor the nocdtrcts option is given, the hardware flow control setting for the serial port is left unchanged. 端末設定の表示、または変更を行います。. 4-stable tree Date: Wed, 22 Nov 2023. [requires _BSD_SOURCE or _SVID_SOURCE] c_lflag flag constants: ISIG When any of the characters INTR, QUIT, SUSP, or DSUSP are received, generate the corresponding signal. Mandatory arguments to long options are mandatory for short options too. hupcl -hupcl, Stop asserting modem control (do not stop) asserting modem control on last close. Re: enable/disable RS232 flow control. If you enable hardware flow control (CRTSCTS in "man termios", or "stty crtscts -F /dev/ttyAMA0", or pySerial rtscts=True), then sending will take place only when CTS is asserted. UNIX에서 시리얼 장치를 다루는 것은 시리얼 터미널의 전통적 방법에 크게 의존하고 있다. 0. This enables RTS/CTS hardware flow control in the Linux device driver. cu command modify "crtscts" option and the only way to push it forward is to run "stty -F /dev/ttyS0 -crtscts". 5 252/491] tty: serial:. First of all, choose one of the machines as a 'server', setting up a getty on the serial port so you can test that you do have connectivity using minicom to access the serial port on the 'client'. It is good practice to call sudo stty -F /dev/ttyAMA0 9600 crtscts to reconfigure the port for hardware flow control before each plot( adjust baud to match your machine). I've added the 1 stop bit flag and disable hardware flow control, but it program still waits on the read function. When I try to use man, I have this message: WARNING: terminal is not fully functional - (press RETURN) and limited control on navigation. たとえば、 RTS/CTS によるフロー制御を行うモデムが接続されている場合の crtscts などのパラメータの初期化が行われます。 ロッキングデバイスは、ポートの設定をロックし、 他のユーザやプログラムにこれらを変更されることのないようにするために利用. This is probably just what you expect. Introduction 华为me909s是基于海思芯片方案的物联网无线通信模块，ME909s系列4G模块集成华为海思芯片平台，继承华为领先的LTE技术，集成DDR降低成本，采用车规级质量管控。同时作为全球首款Cat4 LTE工业模块，同步开放FOTA易升级、降低维护成本。 ME909s系列是车载、跟踪、工业路由器、安防监控mossheim added this to the 3. Part Number: CC2652R Tool/software: Linux Hi, i tried to follow this guide . Share. igrr closed this as completed on Feb 10, 2015. c_cflag |= CREAD | CS8 | HUPCL | CLOCAL | CRTSCTS; The full source code is listed as follows:17. Remember that communication programs change these settings so you may want to check them after you have started. Here is output (nothing about parity bit and baud rate): Description. Linux offers various tools and commands to access serial ports. 168. Then if cat /dev/ttyUSB0 has been listening, I get the following output: -2. The Pi does not remember port configuration very well. 0. It's possible to setup a serial port communication using hardware flow control with the RTS/CTS pins (CRTSCTS flag for tcsetattr), but there is no way to use the DTR/DSR pins for flow control in a reliable and efficient way. If I change the irq of ttyS0 to 0 and then echo some string to ttyS0, the stats are changing according to the length of the string. vim works fine on the first invocation on a remote Windows host, but further use leads to my terminal getting messed up. So output is delivered in a way that would make sense in an interactive terminal. Answer: Example 1: UART1 in DTE mode. FT232RL is FTDI and has good support for windows drivers. com, gregkh@linuxfoundation. 0. Also I'm tryed baudrate: 115200 & rtscts: false in advanced configuration. Xresources, I set XTerm*ptyInitialErase: true . The CRTSCTS is (not in POSIX) Enable RTS/CTS (hardware) flow control. lecture materialsLinuxのC言語でシリアル通信に使うtermios構造体のc_cflag変数についてメモ。 数値はもしかしたら環境依存です。後に示すプログラムを実行して確認しました。 名前 値 説明 CBAUD 0x0000100F ボーレートのマスク。値は※1 CSIZE 0x00000030 データ長のマスク。値は※2 CSTO…patch to fix this. PC ( usually, DTE device): PC_UART_CTS ----INPUT; PC_UART_RTS---OUTPUT. 对串口实现控制的时候同样要用到termio结构体。. If the CRTSCTS flag is clear, the state of CTS has no effect. Perhaps even more so than setserial, the stty command provides a bewildering number of characteristics you can configure. The system usually recognizes the Ctrl-J key sequence when the parameters that control Enter key processing are messed up. h file.