Twisted is a “batteries included” networking engine for writing, testing, and deploying event-driven clients and servers in Python. It comes with off-the-shelf support for popular networking protocols like HTTP, IMAP, IRC, SMTP, POP3, IMAP, DNS, FTP, and more. Reliably Reading from the Serial Port in Python. Ask Question Asked 4 years, 11 months ago. I'm working on the very basic stage of this which is simply RPi2 listening to the serial port and printing whatever it recieves. My code is as follows. Browse other questions tagged python serial.
asyncio is a library to write concurrent code usingthe async/await syntax.
asyncio is used as a foundation for multiple Python asynchronousframeworks that provide high-performance network and web-servers,database connection libraries, distributed task queues, etc.
asyncio is often a perfect fit for IO-bound and high-levelstructured network code.
asyncio provides a set of high-level APIs to:
run Python coroutines concurrently andhave full control over their execution;
perform network IO and IPC;
control subprocesses;
distribute tasks via queues;
synchronize concurrent code;
Additionally, there are low-level APIs forlibrary and framework developers to:
create and manage event loops, whichprovide asynchronous APIs for networking,running subprocesses,handling OSsignals, etc;
implement efficient protocols usingtransports;
bridge callback-based libraries and codewith async/await syntax.
Reference
High-level APIs
Low-level APIs
Guides and Tutorials
Note
The source code for asyncio can be found in Lib/asyncio/.
Introduction
To use Python as a graphical interface for an Arduino powered robot, programmatically read the USB with the pySerial library. However, waiting for input from pySerial's Serial object is blocking, which means that it will prevent your GUI from being responsive. The process cannot update buttons or react to input because it is busy waiting for the serial to say something.
The first key is to use the root.after(milliseconds) method to run a non-blocking version of read in the tkinter main loop. Keep in mind that when TkInter gets to the root.mainloop() method, it is running its own while loop. It needs the things in there to run every now and then in order to make the interface respond to interactions. If you are running your own infinite loop anywhere in the code, the GUI will freeze up. Alternatively, you could write your own infinite loop, and call root.update() yourself occasionally. Both methods achieve basically the same goal of updating the GUI.
However, the real issue is making sure that reading from serial is non-blocking. Normally, the Serial.read() and Serial.readline() will hold up the whole program until it has enough information to give. For example, a Serial.readline() won't print anything until there is a whole line to return, which in some cases might be never! Even using the after() and update() methods will still not allow the UI to be updated in this case, since the function never ends. This problem can be avoided with the timeout=0 option when enitializing the Serial object, which will cause it to return nothing unless something is already waiting in the Serial object's buffer.