1000 lugares que ver antes de morir pdf descargar gratis para. I have a project where I need to send commands to a device and receive fixed length data back from it. This needs to be done through a serial port (till the device is updated). There is also a Kermit send to the device as well. I have seen some information on doing text through a serial port, mostly where arbitrary length data is returned at undetermined times. Does anyone know the best way to do command/response type communication through a serial port? Can the serial port class be used without events when this type of communication is needed, or am I going to be stuck with figuring out how to work with the threading, waiting for data, etc.? Well, since no one has replied to your post, I'll give it a try. We work with instrumentation here, communicating with the devices over actual or virtual serial ports, or over a USB connection to embedded FTDI chips. Now I should caution you that our experience is limited to passing strings back and forth. My guess is that working with binary data across a serial port might pose a problem that I've never encountered, but I can tell you that Microsoft's SerialPort Class works exceptionally well when the data passed back and forth are printable strings, for instance. Determinism and possibilism in geography pdf notes online free. Possibilism he concept that the physical. Notes Quantitative Geography. Determinism and Possibilism. Determinism is the doctrine which stubbornly. In the past the study of foreign lands has been classified as regional geography. The nature of cultural geography.pdf - Possibilism. Environmental Determinism vs. Possibilism Environmental. Microsoft does all the heavy lifting. Users need only instantiate the SerialPort class, open a serial port, and attach their data-receive function to the event (i.e. Subscribe to the event). Heck, even I can do THAT. You mention threading as a concern. Well there IS some threading going on but it's largely invisible to you. Your data-receive function will be operating on a different thread, but that's not much of a problem unless your data-receive function attempts to display the data on a form or interacts with an object subject to access by other threads (in which case, you might consider locks or other exclusionary measures). In summary, it has been my (our) experience that the SerialPort class is simple to use and very reliable (but in your particular case, I should restate: working with binary data may introduce complications I've never encountered, and thus cannot address). You'll like it! The data will be extracted from the received stream into a structure. The data in the structure will then be displayed on a form. All of this occurs sequentially. The send/response is initiated by a button or tab click, the external device is queried, the data interpreted, then presented on the form, then everything stops till another click. There is only one exception and that is a trigger by a timer that basically does the same as the button click on the form. It calls the same routines. However all serial communication takes place as a series of bytes, and the order of the two bytes in an int matters. The Arduino uses the little-endian system. A simple way to send values as binary data is to use a struct and an union. A struct can create a data element with several variables, each with a different type if necessary. Hindi writing in ms word. What Is Multilevel List In Ms Word In Hindi? How Do I Use A Multilevel List In Ms Word In Hindi? How Can I Create A Multi Level Bulleted List In Ms Word In Hindi? Learn All Types of List Designing in MS Word in Hindi. Step by Step Tutorial Helpful in all Types of computer courses such as rscit, ccc, o level, pgdca etc. This is a Useful Task for Office. This thing was originally written in C++ with QT Creator for the GUI. I am trying to get away from the multiple product issues and stick with straight C#/Forms. Andy, I just copied your code to a project here and (after a coupla changes of the sort 'internal' to 'public' granting myself access to your functions) it works just fine. I'm seeing and responding to 'DataReceived' calls. When you applied the null modem, did you have it loop back? You didn't leave it 'open-ended' did you? Anyway, your code's workin' just fine here. Re the polling vs responding to DataReceived. Polling is a perfectly fine way to proceed. Here, however, where the delay can be measured in seconds ( especially if motion is involved!) that's a potentially long time to poll; time which might be more profitably spent addressing other issues. On the other hand, if the response is immediate or reasonably so, then either way is fine. Best o' luck. Well, OK, maybe I spoke too soon. (I spoke as soon as the breakpoint was hit in Data received). There might be a problem in that first statement (SerialPort1.BytesToRead!= BytesToRead ). At that point, 'BytesToRead' is zero. I just resolved that issue by setting 'BytesToRead' as follows. SerialPort1.Write(Buffer, 0, (BytesToRead = Len)); in function 'PutData'. Incidentally, it's not clear to me that it will always be the case that datareceived is called ONLY after all bytes to be read have been read. That is, you might have to capture data on an accrual basis. Just a thought.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |