Logisim 2.7.1 fixes bugs, improves file handling
March 21, 2011 [change log]
Logisim, a graphical design and simulation tool for logic circuits, is now at version 2.7.1. This release's primary purpose is to address several issue discovered since 2.7.0 was released two weeks ago.
One of the primary bugs addressed in this release is one where a user could inadvertently change a component's attribute to an invalid value. The circuit would typically continue to work normally, but when the file is later reloaded, the file would refuse to load. This release repairs the cause of the invalid value assignments; and it enhances the file-loading process so that a dialog box appears explaining any problems found, and the portion of the file that could be interpreted is still loaded.
Another issue found in 2.7.0 was in the behavior of the transistors. In particular, a transistor would "convert" a floating (Z) value into an error value when told to transmit its source input; now, floating values are transmitted as floating values.
Besides addressing many other issues besides these, this version also adds a "Select Location" attribute to the multiplexer, demultiplexer, and decoder, allowing the user to configure where these components' select (and enable) inputs are located relative to the component.
Finally, this release marks the introduction of a mailing list where users can subscribe to hear about new developments regarding Logisim. We promise that the traffic on this list will average below one message per month. To subscribe, go to https://lists.sourceforge.net/lists/listinfo/circuit-announce
Educational institutions around the world use Logisim as an aid to teaching about digital logic and computer architecture. As a Java application, Logisim can run on most major operating systems. Read more about Logisim at http://www.cburch.com/logisim/, and download it from SourceForge.net at http://sourceforge.net/projects/circuit/.
Logisim 2.7.0 has simulation tree, Greek, much more
March 7, 2011 [change log]
Logisim, a graphical design and simulation tool for logic circuits, is now at version 2.7.0. The new version includes numerous enhancements and fixes; the most radical are a new Wiring library, a new method for drawing splitters, and enhancements to the main window's left-side explorer and attribute pane.
This version introduces the Wiring
library, into which
have been moved the circuit components previously found in
Base
: splitter, pin, probe, clock, tunnel, pull resistor,
and bit extender (and also constant, previously located in
Gates
). Additionally, the Wiring
library now
includes a transistor, transmission gate, power, and ground.
Another major change was in how splitters are drawn. The new
technique conforms more closely to traditional circuit diagrams,
and it includes labels showing the bit(s) to which each split
end corresponds. The new Appearance
attribute allows one
to continue using the older technique, and projects created in
older versions of Logisim will continue to load using this
legacy support. However, projects can easily switch to the new
appearance with labels by changing the splitters' Appearance
attribute to Centered
.
The GUI has also received several updates. The explorer pane
in the upper left corner has traditionally shown the current
project's circuits and libraries; this is now called its
Toolbox
view. However, one can switch the explorer pane
to instead show the Simulation Tree,
which includes a
toolbar for controlling the simulation and the hierarchy of
subcircuits in the current simulation. This provides a
visualization of the full hierarchy as well as an alternative to
right-clicking subcircuits (or double-clicking them using the
Poke Tool) to descend into viewing their states. Another notable
enhancement to the GUI is an addition of a title bar to the
attribute table, which indicates whose attributes are currently
being displayed.
Additional features include a Greek translation of the GUI
elements, labels specific to one instance of a subcircuit, an
enable input for multiplexers/demultiplexers/decoders, an Output
Value attribute for gates allowing them to emit floating values
(permitting wired-and and wired-or logic), and support for
product-of-sums expressions in the combinational analysis
module. This version also marks the removal of the Legacy
library and other code meant for supporting projects built in
Logisim 1.0. And the project toolbar
— previously
disabled by default — is now always enabled.
Educational institutions around the world use Logisim as an aid to teaching about digital logic and computer architecture. As a Java application, Logisim can run on most major operating systems. Read more about Logisim at http://www.cburch.com/logisim/, and download it from SourceForge.net at http://sourceforge.net/projects/circuit/.
Discussing Logisim's future at SIGCSE
January 24, 2011
At a birds of the feather
session in the upcoming SIGCSE
conference, the developer behind Logisim, Carl Burch, will lead
a discussion on future development directions for Logisim. In
addition to this discussion, this should be an opportunity to
learn from others who use Logisim in their classes. SIGCSE, the
primary conference concerning computer science education in the
United States, will be March 9-12, 2011, at Dallas, Texas. The
Logisim session is scheduled for 6:10pm, Thursday, March 10,
2011, in State Room 2. More information about conference
registration is at:
http://db.grinnell.edu/sigcse/sigcse2011/
—
the early registration deadline is January 31, 2011.
Educational institutions around the world use Logisim as an aid to teaching about digital logic and computer architecture. As a Java application, Logisim can run on most major operating systems. Read more about Logisim at http://www.cburch.com/logisim/, and download it from SourceForge.net at http://sourceforge.net/projects/circuit/.