Allen Denver Microsoft Windows Developer Support December 11, 1995 Summary: Learn about serial communications in Microsoft Windows. Report Builder Keygen Crack. The Multithreaded TTY (MTTTY) sample is included with this article.

The most popular are Code Designer from CSMicro Systems and Microcode Studio from Mecanique. Mecanique MCSX SerialCom Details file info: Serial Communicator. Common Pitfalls. That’s about all there is to serial communication. I’d like to leave you with a few common mistakes that are easy for an engineer of any.

(35 printed pages) for this technical article. Contents Overview This article provides a foundation for learning about serial communications in Windows. This article assumes you are familiar with the fundamentals of multiple threading and synchronization in Windows. In addition, a basic familiarity of the heap functions is useful to fully comprehend the memory management methods used by the sample, MTTTY, included with this article.

Application programming interfaces (APIs) that control user interface features of windows and dialog boxes, though not discussed here, are useful to know in order to fully comprehend the sample provided with this article. Readers unfamiliar with general Windows programming practices should learn some of the fundamentals of general Windows programming before taking on serial communications. In other words, get your feet wet before diving in head first. (36 printed pages) Introduction This article does not discuss TAPI.

TAPI does deserve mention, however, in that it very nicely implements modem interfacing and call controlling. A production application that works with modems and makes telephone calls should implement these features using the TAPI interface. This will allow seamless integration with the other TAPI-enabled applications that a user may have. Furthermore, this article does not discuss some of the configuration functions, such as GetCommProperties. The sample included with this article, MTTTY: Multithreaded TTY (4918.exe), implements many of the features discussed here. It uses three threads in its implementation: a user interface thread that does memory management, a writer thread that controls all writing, and a reader/status thread that reads data and handles status changes on the port. The sample employs a few different data heaps for memory management.

It also makes extensive use of synchronization methods to facilitate communication between threads. Opening a Port The CreateFile function opens a communications port. There are two ways to call CreateFile to open the communications port: overlapped and nonoverlapped. The following is the proper way to open a communications resource for overlapped operation. HANDLE hComm; hComm = CreateFile( gszPort, GENERIC_READ GENERIC_WRITE, 0, 0, OPEN_EXISTING, FILE_FLAG_OVERLAPPED, 0); if (hComm == INVALID_HANDLE_VALUE) // error opening port; abort Removal of the FILE_FLAG_OVERLAPPED flag from the call to CreateFile specifies nonoverlapped operation. The next section discusses overlapped and nonoverlapped operations.

The Platform SDK documentation states that when opening a communications port, the call to CreateFile has the following requirements: • fdwShareMode must be zero. Communications ports cannot be shared in the same manner that files are shared.

Applications using TAPI can use the TAPI functions to facilitate sharing resources between applications. For applications not using TAPI, handle inheritance or duplication is necessary to share the communications port. Handle duplication is beyond the scope of this article; please refer to the Platform SDK documentation for more information. • fdwCreate must specify the OPEN_EXISTING flag. • hTemplateFile parameter must be NULL. One thing to note about port names is that traditionally they have been COM1, COM2, COM3, or COM4.

The Windows API does not provide any mechanism for determining what ports exist on a system. Some systems even have more ports than the traditional maximum of four. Fantacalcio Manager - Top Edition 2006-2007. Hardware vendors and serial-device-driver writers are free to name the ports anything they like. For this reason, it is best that users have the ability to specify the port name they want to use. If a port does not exist, an error will occur (ERROR_FILE_NOT_FOUND) after attempting to open the port, and the user should be notified that the port isn't available.

Reading and Writing Reading from and writing to communications ports in Windows is very similar to file input/output (I/O) in Windows. In fact, the functions that accomplish file I/O are the same functions used for serial I/O. I/O can be done either of two ways: overlapped or nonoverlapped. The Platform SDK documentation uses the terms asynchronous and synchronous to connote these types of I/O operations. This article, however, uses the terms overlapped and nonoverlapped.