Error Reading From The Serial Port
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Reading Serial Port C#
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Reading Serial Port Linux
Device After Unplugging and Replugging Connector up vote 3 down vote favorite I'm have a Linux application that is supposed to read from serial device /dev/ttyS0. The serial device is opened in the following manner: // Open the serial port if((serial_device = open("/dev/ttyS0", O_RDWR | O_NOCTTY)) < 0){ fprintf(stderr, "ERROR: Open\n"); exit(EXIT_FAILURE); } // Get serial device attributes if(tcgetattr(serial_device,&options)){ fprintf(stderr, "ERROR: Terminal Get Attributes\n"); exit(EXIT_FAILURE); reading serial port in java } cfsetspeed(&options,speed); // Set I/O baud rates cfmakeraw(&options); // Set options to transceive raw data options.c_cflag |= (CLOCAL | CREAD); // Enable the receiver and set local mode options.c_cflag &= ~CSTOPB; // 1 stop bit options.c_cflag &= ~CRTSCTS; // Disable hardware flow control options.c_cc[VMIN] = 1; // Minimum number of characters to read options.c_cc[VTIME] = 10; // One second timeout // Set the new serial device attributes if(tcsetattr(serial_device, TCSANOW, &options)){ fprintf(stderr, "ERROR: Terminal Set Attributes\n"); exit(EXIT_FAILURE); } I then use the select function to try and read from the serial device: // Flush I/O Bffer if(tcflush(serial_device,TCIOFLUSH)){ fprintf(stderr, "ERROR: I/O Flush\n"); exit(EXIT_FAILURE); } // Write message to board if(write(serial_device,msg, strlen(msg)) != (int)strlen(msg)){ fprintf(stderr, "ERROR: Write\n"); exit(EXIT_FAILURE); } switch(select(serial_device+1, &set, NULL, NULL, &timeout)){ // Error case -1: fprintf(stderr, "ERROR: Select\n"); exit(EXIT_FAILURE); // Timeout case 0: success = false; break; // Input ready default: // Try to read a character switch(read(serial_device, &c, 1)){ // Error (miss) case -1: success = false; break; // Got a character default: msg[i++] = c; break; } break; } // Set 200ms timeout this->timeout.tv_sec = 0; this->timeout.tv_usec = 200000; } I've tried reopening the port by determining if the read was not suc
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Reading Serial Port Visual Basic
Discuss the workings and policies of this site About Us Learn matlab reading serial port more about Stack Overflow the company Business Learn more about hiring developers or posting ads with us writing serial port Stack Overflow Questions Jobs Documentation Tags Users Badges Ask Question x Dismiss Join the Stack Overflow Community Stack Overflow is a community of 4.7 million programmers, just like http://stackoverflow.com/questions/17279957/unable-to-read-from-serial-device-after-unplugging-and-replugging-connector you, helping each other. Join them; it only takes a minute: Sign up Linux - serial port read returning EAGAIN up vote 8 down vote favorite 2 I am having some trouble reading some data from a serial port I opened the following way. I've used this instance of code plenty of times and all worked fine, http://stackoverflow.com/questions/1613916/linux-serial-port-read-returning-eagain but now, for some reason that I cant figure out, I am completely unable to read anything from the serial port. I am able to write and all is correctly received on the other end, but the replies (which are correctly sent) are never received (No, the cables are all ok ;) ) The code I used to open the serial port is the following: fd = open("/dev/ttyUSB0", O_RDWR | O_NONBLOCK | O_NOCTTY); if (fd == -1) { Aviso("Unable to open port"); return (fd); } else { //Get the current options for the port... bzero(&options, sizeof(options)); /* clear struct for new port settings */ tcgetattr(fd, &options); /*-- Set baud rate -------------------------------------------------------*/ if (cfsetispeed(&options, SerialBaudInterp(BaudRate))==-1) perror("On cfsetispeed:"); if (cfsetospeed(&options, SerialBaudInterp(BaudRate))==-1) perror("On cfsetospeed:"); //Enable the receiver and set local mode... options.c_cflag |= (CLOCAL | CREAD); options.c_cflag &= ~PARENB; /* Parity disabled */ options.c_cflag &= ~CSTOPB; options.c_cflag &= ~CSIZE; /* Mask the character size bits */ options.c_cflag |= SerialDataBitsInterp(8); /* CS8 - Selects 8 data bits */ options.c_cflag &= ~CRTSCTS; // di
Categories 94.4KAnnouncements 739 Microcontrollers 62.1K Propeller 1 25.9K Propeller 2 775 BASIC Stamp 18.4K Learn 1.8K Robotics 7.5K Accessories 3.1K General Discussion 19.3K Error reading from the serial port (timeout) wandrson Posts: 5 April 2007 edited July 2007 in Microcontrollers Vote Up0Vote Down I http://forums.parallax.com/discussion/93736/error-reading-from-the-serial-port-timeout have a Javalin Stamp on a USB BOE. After programing it with a small test program https://www.mathworks.com/help/matlab/ref/serial.fscanf.html I tried a quick change and to reprogram it. I get the following error: "Error reading from the serial port (timeout)" The IDE successfully finds the Javalin but programming doesn't work. I have a LCD AppMod installed and it appears the IDE is successfully reseting the Javalin. The LCD display goes blank when the IDE says reseting. It doesn't display anything serial port else until I hit the reset button and it displays the text from the last program I successfully downloaded. Any suggestions? Tagged: javelin Comments 8 Comments sorted by Date Added Votes Peter Verkaik Posts: 3,956 April 2007 edited April 2007 Vote Up0Vote Down See this thread http://forums.parallax.com/showthread.php?p=585022 Hit the program button as soon as possible after recycling power to the javelin, to prevent the javelin from executing the current program. regards peter wandrson Posts: 5 April 2007 edited reading serial port April 2007 Vote Up0Vote Down I just tried this several times, including not powering the BOE until after starting the batch file and I get the same error. Robot Freak Posts: 168 April 2007 edited April 2007 Vote Up0Vote Down Chris Savage said... Hello, I attempted to cover this issue early on but was assured there were hardware issues. The USB BOE exhibits a known issue on some (rare) computer when a very small program is downloaded into the Javelin. This causes a timeout to occur. The problem doesn't appear to happen when using a Serial BOE with our USB to 232 adapter or when using a straight serial port. It seems to be timing related but what you will need to do is get access to a serial BOE or other development board and connect to a PC which has an on-board RS-232 Serial Port (preferably not a laptop). Try again, and if it doesn't work try the attached Prime Javelin program. Again, this really should be done from a direct serial port on a desktop. In the future avoid downloading very small programs onto the Javelin when using the USB BOE. I hope this helps. Take care. Chris Savage Parallax Technical Support wandrson Posts: 5 April 2007 edited April 2007 Vote Up0Vote Down Thanks for the response. I thought that the Javalin was supposed to be compatible wi
Search All Support Resources Support Documentation MathWorks Search MathWorks.com MathWorks Documentation Support Documentation Toggle navigation Trial Software Product Updates Documentation Home MATLAB Examples Functions Release Notes PDF Documentation Data Import and Analysis Data Import and Export Serial Port Devices MATLAB Functions fscanf (serial) On this page Syntax Description Examples More About Tips Rules for Completing a Read Operation with fscanf See Also This is machine translation Translated by Mouse over text to see original. Click the button below to return to the English verison of the page. Back to English × Translate This Page Select Language Bulgarian Catalan Chinese Simplified Chinese Traditional Czech Danish Dutch English Estonian Finnish French German Greek Haitian Creole Hindi Hmong Daw Hungarian Indonesian Italian Japanese Korean Latvian Lithuanian Malay Maltese Norwegian Polish Portuguese Romanian Russian Slovak Slovenian Spanish Swedish Thai Turkish Ukrainian Vietnamese Welsh MathWorks Machine Translation The automated translation of this page is provided by a general purpose third party translator tool. MathWorks does not warrant, and disclaims all liability for, the accuracy, suitability, or fitness for purpose of the translation. Translate fscanf (serial)Read ASCII data from device, and format as text SyntaxA = fscanf(obj)
A = fscanf(obj,'format
')A = fscanf(obj,'format',size)[A,count] = fscanf(...)[A,count,msg] = fscanf(...)DescriptionA = fscanf(obj) reads ASCII data from the device connected to the serial port object, obj, and returns it to A. The data is converted to text using the %c format. For binary data, use fread.A = fscanf(obj,'format
') reads data and converts it according to format. format is a C language conversion specification. Conversion specifications involve the % character and the conversion characters d, i, o, u, x, X, f, e, E, g, G, c, an