Logisim: Release history

Version 2.1.8 (28 Feb 2009)

Feature: Previously when a JAR library was loaded the user would always have to address a dialog in which the user would type the name of the class that specifies the contents of the library. The JAR library developer now has the opion to include a 'Library-Class' attribute in the JAR's manifest; if present, the dialog box does not appear.

Bug fix: The program offered the option to add random noise into gate delays, but 2.1.7 ignored it and never added random noise. (Prior to 2.1.7, the option was ignored and random noise was always added). This checkbox is now effective.

Bug fix: Some components' attributes are configured through a dialog box, such as the color dialog with the LED component. Prior to 2.1.8, resizing this dialog didn't always work particularly well. Thanks to Christophe Jacquet for identifying the bug and suggesing a fix.

Version 2.1.7 (15 Jan 2009)

Bug fix: The program offered the option to add random noise into gate delays, so when a latch gets into an oscillating state it will eventually reach a point where it is not oscillating. This was disabled by default, because it can also lead to erroneous computations with other circuits. Nonetheless, the random noise was added even when the option was disabled. (Thanks to stultuses who provided a circuit that led to the discovery of this bug.)

Bug fix: The simulator could get into a tight loop, effectively freezing Logisim, if a tick was pending while an oscillation is detected. Thanks to Christophe Jacquet for identifying the bug and suggesting a fix.

Bug fix: If the circuit currently being viewed was removed the project, the circuit would continue to be displayed in the viewing window.

Feature: Added a "Step Simulation" menu item, which steps the simulation just a single step. Any points in the circuit affected by the step are indicated with blue circles. This feature can help with debugging circuits that have oscillations.

Feature: Added several faster options in the "Tick Frequency" submenu, going up to 1024 Hz.

Usability enhancement: When double-clicking a circuit in the explorer, Logisim would choose that as a tool and then display the circuit. The selected tool would continue to be that circuit, even though it was useless. The program now reverts to the previously selected tool.

Usability enhancement: When adding a subcircuit into a circuit, the displayed "ghost" now displays the notch indicating the subcircuit's orientation.

Documentation error: The first tutorial page described a XOR's output exactly wrong.

Version 2.1.6 (7 May 2007)

Feature: When moving components horizontally or vertically, wires can "stretch" to maintain connections. This is disabled by default, because I want to give users a chance to find bugs and to suggest modifications; it will probably be permanently enabled in Logisim 2.2, without an option to remove it. To enable it, visit the Experimental tab in the Preferences window (under the File menu - or the Logisim menu on Macs).

Feature: User can choose to use OpenGL or Direct3D graphics acceleration via the Experimental tab in the Preferences window (under the File menu - or the Logisim menu on Macs). Timothy Baldridge reports that one some recent versions of Java (starting with later versions of Java 5), adding "-Dsun.java2d.d3d=True" to the command line speeds the graphics rendering considerably. This is an attempt to allow the user to configure this behavior as the default, without resorting to the command line; it will require you to restart Logisim to take effect. I'm not absolutely sure it will work, so I'm placing it as an experimental feature for now.

Feature: Immediately after inserting a component or a wire, pressing the backspace key will undo the addition.

Feature: RAM and ROM components are designed to handle up to 24 bits of address space, rather than just 12 bits.

Feature: Gates may be configured to have exactly 2 inputs.

Feature: The limit on the number of inputs/outputs in the Combinational Analysis module has been lifted to 12 (from 8). Allowing more inputs would seem to require significant work; even with 12 inputs, a complex expression can take about 15 seconds to respond to a bit being flipped in the truth table.

Bug fix: Button component in I/O library now starts out with "zero" output, rather than "unknown."

Bug fix: Bit Selector component in Plexers library would go into infinite loop when the number of bits in the output was greater than or equal to the number in the input.

Bug fix: The memory image file would sometimes fail to load due to an off-by-one error. (An example where it would fail would be when the memory image starts with 65 zeroes followed by a nonzero value.) Also, a saved memory image file was missing a line termination character for the final line (this wasn't really causing any trouble).

Bug fix: An exception occurred when bringing up the splash screen on some installations. I doubt the splash screen was going to be the only problem on such systems, but anyway Logisim now attempts to start without the splash screen in such situations.

Bug fix: Systems using GCJ rather than Sun's JVM ran into exceptions when encountering the nonexistent classes for customizing the MacOS UI. I believe all such problems are now avoided.

Bug fix: An exception could occur when retrieving the clipboard while pasting into the truth table.

UI change: The Window menu's Zoom option has been renamed to "Maximize" on non-Macintosh systems.

Version 2.1.5 (27 Nov 2006)

Feature: Added support for DIN 40700 gates, an older German system for drawing gates that was superseded in Germany by the rectangular standard in 1976, but which apparently is still preferred by some designers.

Bug fix: With a 32-bit memory, values that take 32 bits would not be loaded properly.

Bug fix: When loading the hex editor for wide values on a small screen, the window could be much wider than the screen.

Bug fix: When an existing multi-bit pin's facing was changed, it was drawn with the wrong border (as if it were a 1-bit pin).

Bug fix (?): The MacOS support led to the program being unusable when loaded using GCJ. I'm not entirely confident that the changes address his issue, since I haven't installed GCJ to be able to test it. Reports of GCJ compatibility would be welcome.

Appearance change: Toolbar buttons don't have individual borders, and toolbar separators are visible.

Appearance change: The "attribute halo" for tools in the explorer or toolbar are drawn as a solid teal background, rather than as a barely-visible teal circle.

Version 2.1.3 (14 Oct 2006)

Thanks to Kevin Walsh of Cornell University, who submitted most of the suggestions, as well as some of the bug fixes, appearing in this release.

Feature: Plexers components have a Facing attribute.

Feature: Added Input/Output library, with Button, LED, and 7-Segment Display.

Feature: User can configure the location of the toolbar, or hide it, via a combo box under the Toolbar tab in the Project Options window.

Bug fix: Rarely, changing a splitter's division of bits while simulation was enabled would result in an exception that would disable all future simulation.

Bug fix: An exception during value propagation only halts the simulation temporarily, with a descriptive message for the user. (This simply makes Logisim work a bit more elegantly for any future unknown simulation bugs.)

Bug fix: If a circuit contains a 32-bit constant with the topmost bit set, then the resulting file could not be opened within Logisim.

Bug fix: A 32-bit register's value was not editable via the keyboard due to a bug in BitWidth's getMask method.

Version 2.1.2 (12 Jun 2006)

Feature: The Probe component has a newly added Radix attribute.

Feature: User can configure the radix used to display values when wires are poked, via new options in Canvas panel of Project Options window.

Feature: Added "zoom out" options to the Zoom menu in the Project Options window.

Bug fix: In loading memory images into RAM/ROM with a Data Width more than 16, only the bottom 16 bits of each value were taken (and sign-extended).

Bug fix: Changing the facing attribute for the Probe component resized it to hold only one bit, even if multiple bits were being viewed.

Bug fix: Removed rare "ComodificationException" that sometimes occurred during startup within the Simulator class.

Version 2.1.1 (17 May 2006)

Bug fix: When simulation is disabled, many actions (such as changing the circuit viewed and loading memory) were not displayed in the window immediately.

Bug fix: On ROMs, changes to the data bit width or address bit width were not reflected in the in-circuit display as they ought.

Bug fix: The current component whose attribute set is displayed follows copy/cut and paste a bit more faithfully.

Version 2.1.0 (11 May 2006)

Feature: Spanish translation included, contributed by Pablo Leal Ramos. For platforms with incompatibilities with accented characters, the user may opt for them to be replaced with non-accented substitutions. Added "-accents" command-line option.

Feature: Added ROM component to the built-in Memory library.

Feature: RAM component's pop-up menu has an "Edit Contents" option, which brings up a separate window containing a proper hex editor.

Feature: RAM image files use run-length encoding, providing some level of compression. (Old image files are still compatible.)

Feature: Added Tick Once item into Simulate menu.

Feature: In the combinational analysis module, the truth table can be navigated using the keyboard. Also, cut/copy/paste can be used on the truth table; the clipboard is compatible with other applications accepting tab-delimited text (such as a spreadsheet).

Bug fix: When the Data Bits attribute is changed, the RAM updates the number of columns displayed within the component as appropriate.

Bug fix: After cutting the selection in the circuit, and then pasting and dragging the selection, subsequent drags were not forced onto the grid when appropriate.

Bug fix: When pasting a component from the clipboard, the displayed set of attributes follows what has been selected.

Bug fix: Copying a component to the clipboard, then changing that component's attribute, led to a change to the attribute on the clipboard also.

Bug fix: Simply opening the options window associated with the project would enter an action for changing an option. This option could not be undone.

Bug fix: In combinational analysis module, changing or removing variables removed information about the minimized expressions.

Interface change: When asking what to do with unsaved changes, the program now does a "Save" rather than a "Save As."

Interface change: Random noise (included to support latches) is turned off by default.

Logisim 2.1.x release history