**************************************************************
*                                                            *
*                         TIGraph 1.0                        *
*           TI-85 Emulator for Windows 95/98/NT              *
*                                                            *
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This file serves as explanation of TIGraph 1.0.
TIGraph must only be forwarded in combination with this file.
TIGraph 1.0 is freeware.





Contents
~~~~~~~~

a) Introductory Notes
b) Specialities of TIGraph
c) Installing and using TIGraph
d) Questions and answers
e) File-format of the status-file
f) The authors



a) Introductory Notes
~~~~~~~~~~~~~~~~~~~~~

In order to use TIGraph a ROM-file version 10.0 is required.
All rights concerning the ROM of TI-85 are reserved 
with the Texas Instruments Company, and owners of a TI-85 only are 
legally allowed to use the ROM. Again: this program is for 
owners of TI-85 only, because they are the only ones who can legally 
use it!
In "Questions and answers" you will be given more information on ROM 
and ROM-files.


b) Specialities of TIGraph
~~~~~~~~~~~~~~~~~~~~~~~~~~

A new emulator for TI-85 has been born.
Well, of course - there is quite a variety of emulators in the 
net already, but this one has some specialities worth looking at 
it a bit closer:

>> TIGraph can be used in Windows 95/98/NT.
   The user interface has directly been adopted from a real
   calculator, and that's why using it is just as easy as using a 
   calculator. There's no need to learn difficult keyboard-combinations 
   by heart (or even guessing positions of special keys in 
   foreign keyboard layouts) - using the mouse is all you have to do!
   If you would like to replace the Windows calculator by using TIGraph -
   no problem at all!

>> TIGraph is easy to use.
   If you know how to use TI-85 you can start using TIGraph immediately.
   You don't need any knowledge of programming, nor 
   lengthy commandline arguments.
   Just click and calculate!
   When closing you can decide if you want to save the latest 
   results; next time they will automatically be displayed.

>> TIGraph calculates very fast.
   Admittedly, TIGraph is not the fastest emulator in the world, but it 
   is the fastest TI-85 emulator under Windows!
   And no doubt it is faster than an ordinary calculator anyway!

>> TIGraph uses system resources very economically.
   This feature was of special importance for us: all TI-xx emulators in 
   Windows that we know of require almost completely 100% CPU-time 
   (exeption: single step mode). Consequently, there is not much 
   space left to run other applications in a multi-tasking environment.
   TIGraph, however, only requires less than 0.5% CPU-time in idle mode
   (source: Wintop of Microsoft Kerneltoys)!
   Only during particularly complex calculations the average percentage 
   can rise to the maximum. Therefore it is no problem to keep TIGraph 
   active while working with other windows. 


c) Installing and using TIGraph
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

>> Installing
   For installation just copy the file "tigraph.exe" together with the 
   ROM-file in a directory. The ROM-file should be called 
   "ti85rom.bin".
   The program will be started by executing the file "tigraph.exe".

>> Using TIGraph
   When you start for the first time the "display" of TIGraph will 
   initially be totally black. As soon as you click [ON]key the calculator 
   will be activated. After that you can use TIGraph just as easy as 
   the TI-85.
   When closing the TIGraph window a dialog box with three options will 
   be displayed:
   "Yes" ends the program and saves the latest results in a file; 
   "No" ends the program without saving; if you choose 
   "Cancel" (escape key) the program stays activated and you can 
   continue working with it.

>> Additional functions
   You don't necessarily have to call the ROM-file "ti85rom.bin". Just 
   as well, you can separately name the file which saves the status of 
   the calculator (standard: "ti85stat.bin"). 
   For this purpose there are commandline arguments:

   tigraph [/rom:<romfile>] [/ram:<ramfile>]

   <romfile> and <ramfile> indicate the name of the ROM-file or the file
   which serves for loading and saving the status.
   (The square brackets indicate that both parameters are optional.)


d) Questions and Answers
~~~~~~~~~~~~~~~~~~~~~~~~

>> What is a ROM-file?
   There is an integrated memory in the TI-85 including the 
   operating system of the calculator and its calculating routines.
   This memory is called ROM (read only memory), because its
   contents are unchangeable.
   A ROM-file comes into existence when you dump the 
   ROM of the calculator with a suitable program and save it in a 
   file.

>> Where do I get a ROM-file?
   TIGraph requires a ROM-file (ROM-version 10.0) in order to 
   act and calculate exactly like the TI-85.
   You get this file by decovering the ROM of your own calculator. 
   Instructions and suitable programs can be found for example in 
   http://www.ticalc.org.

>> Why does the cursor of TIGraph not flash?
   The flashing of the cursor during the emulation is inhibited by 
   the way in which TIGraph emulates the interrupt system of 
   the TI-85. (This is why the busy-indicator in the top right display 
   also isn't activated.)
   We do regret this, but so the economical usage of system 
   resources is made possible.

>> TIGraph seems not to be working
   Just as the TI-85 you can switch off TIGraph by typing [2nd] [ON]. After 
   that, all keys are deactivated except the [ON] key, and the 
   program might seem not to be working. 
   You can reactivate TIGraph by retyping [ON].


e) File-format of the status-file
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Unfortunately, we were not able to make the format of our status-file 
compatible to the format of any other emulator.
As TIGraph only emulates basic functions of the TI-85, it cannot use 
some data from other file-formats - otherwise compatibility would 
have become a one-way-road!
However, in order to make it possible to keep using "old" 
status-files we display our file-format here:

   Offset       Length          Info
   ------------------------------------------------
   0x0000       0x8000          RAM des TI-85
   0x8000       0x0002          AF
   0x8002       0x0002          BC
   0x8004       0x0002          DE
   0x8006       0x0002          HL
   0x8008       0x0002          IX
   0x800A       0x0002          IY
   0x800C       0x0002          PC
   0x800E       0x0002          SP
   0x8010       0x0002          AF'
   0x8012       0x0002          BC'
   0x8014       0x0002          DE'
   0x8016       0x0002          HL'
   0x8018       0x0001          IFF
   0x8019       0x0001          I
   0x801A       0x0001          power register
   0x801B       0x0001          contrast
   0x801C       0x0001          link register
   0x801D       0x0001          current ROM page number
   0x801E       0x0001          keypadMask
   0x801F       0x0001          lcd state, on/off


f) The authors
~~~~~~~~~~~~~~

We are students of electrical engineering/communication technology
at "Hochschule fuer Technik, Wirtschaft und Kultur Leipzig".
We are very happy to receive ideas, complaints and notification of 
bugs of TIGraph.
Please don't ask for more information on the ROM of TI-85 and 
where to get it - as a matter of fact: we do not answer any 
questions!

Rene Doss       
Joerg Sander

mail: graphcalc@gmx.de


