Usage examples can be found in the examples where two TCP/IP - serial converters are shown, one using threads (the single port server) and an other using select (the multi port server). Note Each new client connection must create a new instance as this object (and the RFC 2217 protocol) has internal state. Project: spi-flash-programmer Author: nfd File: spiflashprogrammerclient.py License: Creative. The first cycle of your while loop seems to go through fine, but your program hangs when it tries ser.readline for the second time. There are a few ways to solve this. My preferred way would be to specify a non-None timeout, perhaps of one second. This would allow ser.readline to return a value even when the device does not send an endline. Python documentation: Read from serial port. Initialize serial device. Data = ser.readline to read the data from serial device while something is.
The
readline
module defines a number of functions to facilitatecompletion and reading/writing of history files from the Python interpreter.This module can be used directly, or via the rlcompleter
module, whichsupports completion of Python identifiers at the interactive prompt. Settingsmade using this module affect the behaviour of both the interpreter’sinteractive prompt and the prompts offered by the built-in input()
function.Python Pyserial Readline Example Java
Readline keybindings may be configured via an initialization file, typically
.inputrc
in your home directory. See Readline Init Filein the GNU Readline manual for information about the format andallowable constructs of that file, and the capabilities of theReadline library in general.Note
![Python Pyserial Readline Example Python Pyserial Readline Example](/uploads/1/1/9/8/119846030/308392104.jpg)
The underlying Readline library API may be implemented bythe
libedit
library instead of GNU readline.On macOS the readline
module detects which library is being usedat run time.The configuration file for
libedit
is different from thatof GNU readline. If you programmatically load configuration stringsyou can check for the text “libedit” in readline.__doc__
to differentiate between GNU readline and libedit.If you use editline/
libedit
readline emulation on macOS, theinitialization file located in your home directory is named.editrc
. For example, the following content in ~/.editrc
willturn ON vi keybindings and TAB completion:Init file¶
The following functions relate to the init file and user configuration:
readline.
parse_and_bind
(string)¶Execute the init line provided in the string argument. This calls
rl_parse_and_bind()
in the underlying library.readline.
read_init_file
([filename])¶Execute a readline initialization file. The default filename is the last filenameused. This calls
rl_read_init_file()
in the underlying library.Line buffer¶
The following functions operate on the line buffer:
readline.
get_line_buffer
()¶Return the current contents of the line buffer (
rl_line_buffer
in the underlying library).readline.
insert_text
(string)¶Insert text into the line buffer at the cursor position. This calls
rl_insert_text()
in the underlying library, but ignoresthe return value.readline.
redisplay
()¶Change what’s displayed on the screen to reflect the current contents of theline buffer. This calls
rl_redisplay()
in the underlying library.History file¶
The following functions operate on a history file:
readline.
read_history_file
([filename])¶Load a readline history file, and append it to the history list.The default filename is
~/.history
. This callsread_history()
in the underlying library.readline.
write_history_file
([filename])¶Save the history list to a readline history file, overwriting anyexisting file. The default filename is
~/.history
. This callswrite_history()
in the underlying library.readline.
append_history_file
(nelements[, filename])¶Append the last nelements items of history to a file. The default filename is
~/.history
. The file must already exist. This callsappend_history()
in the underlying library. This functiononly exists if Python was compiled for a version of the librarythat supports it.readline.
get_history_length
()¶readline.
set_history_length
(length)¶Set or return the desired number of lines to save in the history file.The
write_history_file()
function uses this value to truncatethe history file, by calling history_truncate_file()
inthe underlying library. Negative values implyunlimited history file size.History list¶
The following functions operate on a global history list:
readline.
clear_history
()¶Clear the current history. This calls
clear_history()
in theunderlying library. The Python function only exists if Python wascompiled for a version of the library that supports it.readline.
get_current_history_length
()¶Return the number of items currently in the history. (This is different from
get_history_length()
, which returns the maximum number of lines that willbe written to a history file.)readline.
get_history_item
(index)¶Return the current contents of history item at index. The item indexis one-based. This calls
history_get()
in the underlying library.readline.
remove_history_item
(pos)¶Remove history item specified by its position from the history.The position is zero-based. This calls
remove_history()
inthe underlying library.![Windows Windows](/uploads/1/1/9/8/119846030/467065448.png)
readline.
replace_history_item
(pos, line)¶Replace history item specified by its position with line.The position is zero-based. This calls
replace_history_entry()
in the underlying library.readline.
add_history
(line)¶Append line to the history buffer, as if it was the last line typed.This calls
add_history()
in the underlying library.readline.
set_auto_history
(enabled)¶Enable or disable automatic calls to
add_history()
when readinginput via readline. The enabled argument should be a Boolean valuethat when true, enables auto history, and that when false, disablesauto history.CPython implementation detail: Auto history is enabled by default, and changes to this do not persistacross multiple sessions.
Startup hooks¶
readline.
set_startup_hook
([function])¶Set or remove the function invoked by the
rl_startup_hook
callback of the underlying library. If function is specified, it willbe used as the new hook function; if omitted or None
, any functionalready installed is removed. The hook is called with noarguments just before readline prints the first prompt.readline.
set_pre_input_hook
([function])¶Set or remove the function invoked by the
rl_pre_input_hook
callback of the underlying library. If function is specified, it willbe used as the new hook function; if omitted or None
, anyfunction already installed is removed. The hook is calledwith no arguments after the first prompt has been printed and just beforereadline starts reading input characters. This function only existsif Python was compiled for a version of the library that supports it.Completion¶
The following functions relate to implementing a custom word completionfunction. This is typically operated by the Tab key, and can suggest andautomatically complete a word being typed. By default, Readline is set upto be used by
rlcompleter
to complete Python identifiers forthe interactive interpreter. If the readline
module is to be usedwith a custom completer, a different set of word delimiters should be set.readline.
set_completer
([function])¶Set or remove the completer function. If function is specified, it will beused as the new completer function; if omitted or
None
, any completerfunction already installed is removed. The completer function is called asfunction(text,state)
, for state in 0
, 1
, 2
, …, until itreturns a non-string value. It should return the next possible completionstarting with text.The installed completer function is invoked by the entry_func callbackpassed to
rl_completion_matches()
in the underlying library.The text string comes from the first parameter to therl_attempted_completion_function
callback of theunderlying library.readline.
get_completer
()¶Get the completer function, or
None
if no completer function has been set.readline.
get_completion_type
()¶Get the type of completion being attempted. This returns the
rl_completion_type
variable in the underlying library asan integer.readline.
get_begidx
()¶readline.
get_endidx
()¶Get the beginning or ending index of the completion scope.These indexes are the start and end arguments passed to the
rl_attempted_completion_function
callback of theunderlying library.readline.
set_completer_delims
(string)¶Python Pyserial Readline Examples
readline.
get_completer_delims
()¶Python File Readlines
Set or get the word delimiters for completion. These determine thestart of the word to be considered for completion (the completion scope).These functions access the
rl_completer_word_break_characters
variable in the underlying library.readline.
set_completion_display_matches_hook
([function])¶Set or remove the completion display function. If function isspecified, it will be used as the new completion display function;if omitted or
None
, any completion display function alreadyinstalled is removed. This sets or clears therl_completion_display_matches_hook
callback in theunderlying library. The completion display function is called asfunction(substitution,[matches],longest_match_length)
onceeach time matches need to be displayed.Example¶
The following example demonstrates how to use the
readline
module’shistory reading and writing functions to automatically load and save a historyfile named .python_history
from the user’s home directory. The codebelow would normally be executed automatically during interactive sessionsfrom the user’s PYTHONSTARTUP
file.This code is actually automatically run when Python is run ininteractive mode (see Readline configuration).
The following example achieves the same goal but supports concurrent interactivesessions, by only appending the new history.
The following example extends the
code.InteractiveConsole
class tosupport history save/restore.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.