Doors CS


Doors CS


Assembly shell for the TI-83+/84+


Christopher Mitchell


Release Date

July 11, 2013 (version 7.2)


TI-83+/84+ Flash Application


Z80 Assembly


Doors CS (Doors Calculator Shell) is a popular Flash Application for the TI-83+/84+ calculators, written by Christopher Mitchell (aka Kerm Martian). It functions as a shell on the calculator, providing a GUI for users to load programs, arrange programs into folders, and much more. It is backwards compatible with both MirageOS and Ion programs, making it the most compatible of all TI-83+/84+ shells.


Over the years, Doors CS has become one of the leading shells for the TI-83+/84+ calculators. As of October 6th, 2020, it has been downloaded 105257 times from, and is regularly ranked 67 in downloads for the past seven days.

It contains an extensive list of features, such as (but not limited to):

  • The ability to run any TI-Basic and assembly programs, including those made for Ion, MirageOS or as nostub programs.
  • Programs can be sorted into folders (which can also be nested).
  • A mouse-based GUI.
  • Many built-in libraries, including CALCnet, xLIB, Celtic III and more.

It has been featured many times on, and has a large selection of programs & games that use its library features.


Navigation around the Doors CS GUI is performed using the arrow keys to move the mouse cursor, with [2nd] & [ALPHA] being used to "left" & "right" click respectively. There are also many shortcut keys available.

The user manual is available on the Doors CS Wiki page here.

Development History

Initial development of Doors CS (then known as Doors XP) began in mid-late 2001, as a TI-Basic program. In January 2004, the first stable assembly version was released to the public (version 4.0.0). The first Flash Application version was released in March 2006 (version 5.5.0 Beta).

Nine years after the first release saw the August 2010 release of Doors CS version 7.0, a fully developed shell environment contained in a 2 page Flash Application. As of June 2014, the latest official release is version 7.2 (released July 2013).

In 2013, Christopher released Doors CSE, the equivalent shell for the TI-84+CSE calculator.

A full history of the Doors CS application can be found on the Doors CS Wiki page here.

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