Program:     Lock 83(+)
Version:     1.6
Author:      James Vernon <james@calc.org>
Description: Security Program (Module)
Machines:    TI-83/TI-83+
Language:    Z80 Assembly Code
Platform:    Ion
Released:    September 2000
Size:        TI-83  - 261 bytes
             TI-83+ - 266 bytes


*********************
** Version History **
*********************
v1.0: (512 bytes) - August 1999
- First public release
- Only for the TI-OS on the 83

v1.1: (480 bytes) - April 2000
- Compatible with AShell, SOS, ION 83 and ION 83+
- Just run program to turn calculator off
- Enter passwords of any length (only first 15 characters saved)
- Added backspace function
- Optimised

v1.2: (334 bytes) - April 2000
- Now an ION module
- No longer compatible with AShell or SOS
- Optimised a bit more
- Can only enter up to 15 chars.

v1.3: (342 bytes) - May 2000
- Module for ION83, ION83+
- Added APD (thanks Henk Poley for the idea)
- Released source code again
- Optimised more (again)
- Now you really can only enter up to 15 characters

v1.4: (312 bytes) - May 2000
- Fixed a bug
- Can enter heaps of characters again because this was the bit that caused the program to crash
- Reduced the size a bit

v1.5: (265 bytes) - July 2000
- Optimised way more!
- Only saves the first 10 characters of your password (to save a bit of space :)

v1.6: (261 bytes) - September 2000
- Very final release (unless any bugs are found)
- Shaved off another 4 bytes


********************
** Included Files **
********************
PROGRAM FILES:
zmlock83.83p       TI-83 Version
zmlock83.8xp       TI-83+ Version

DOCUMENTATION:
readme.txt         This document

SOURCE CODE:
zmlock83.z80       All source code included in this file


***********
** Setup **
***********
  TI-83  - Send zmlock83.83p to your calculator
  TI-83+ - Send zmlock83.8xp to your calculator

  You must have Ion (preferably the latest version) installed on your calculator. This can be obtained from http://joewing.calc.org. You also need at least one Ion program on your calculator because Lock 83(+) is a module and can only be used when Ion is running.


**********************
** Using Lock 83(+) **
**********************
  To set a password, press [TRACE] from the Ion program menu. You will be prompted for a password. Once you have set a password, you can press [GRAPH] from the Ion menu to turn off the calculator. When you turn the calculator back on, you will have to enter your password, otherwise you won't be allowed into the calculator. To disable Lock 83(+), press [TRACE] from Ion and enter your old password. Then for the new password, just leave it blank and press [ENTER]. Now pressing [GRAPH] from Ion will do nothing again.

  When you go to change your password and you are prompted to enter your old password, if you enter it wrong the module will exit back to Ion without changing the password.

  When entering a password, if you don't press a key for a couple of seconds, the calculator turns off. Don't worry - this is meant to happen, when you turn it back on you'll be right where you left off. This is just a little APD routine that I've added so the calculator can't sit there and drain your batteries.


************************
** Entering Passwords **
************************
  Any key can be pressed on the calculator for a password, except for the [ON] button, [DEL] and [ENTER]. The [DEL] button is used for backspace. Press [ENTER] when you have finished entering the password. The [ON] button won't do anything. Note that you can't backspace to a previous line.

  Remember that only the first 10 characters of any password you enter are saved.


****************
** Disclaimer **
****************
  If you forget your password and the calculator has been turned off through Lock 83(+), there is nothing you can do. I take no responsibility for your forgetfulness!


Many thanks to the following people:
- Henk Poley for the APD idea!
- Dan Englender for helping me to optimise it and also for helping me find a bug with the 83+ version in v1.1!
- James Matthews for ASMGuru
- Bill Nagel for Password which gave me the idea
- Joe Wingerbermuehle for Ion
- Assembly-83 Mailing List
- Ticalc.org for hosting the mailing list
- Anyone else I forgot to mention!


  If you have any comments, bug reports or other interesting stuff please email me!

Lock 83(+) v1.6
Copyright 1999-2000 TCPA/Jimsoft Software
Written and Programmed by James Vernon <james@calc.org>
http://tcpa.calc.org
ICQ#: 71589304