The TI-89 is a graphing calculator developed by Texas Instruments in 1998. The unit features a 160×100
pixel resolution
LCD and a large amount of
flash memory, and includes TI's
Advanced Mathematics Software. The TI-89 is one of the highest model lines in TI's calculator products, along with the
TI-Nspire. In the summer of 2004, the standard TI-89 was replaced by the TI-89 Titanium. The TI-89 runs on a 32-bit microprocessor, the
Motorola 68000, which nominally runs at 10 or 12
MHz, depending on the calculator's hardware version. The calculator has 256
kB of
RAM, (190 kB of which are available to the user) and 2 MB of
flash memory (700 kB of which is available to the user). The RAM and Flash ROM are used to store expressions,
variables,
programs,
text files, and lists. The TI-89 is essentially a
TI-92 Plus with a limited
keyboard and smaller screen. It was created partially in response to the fact that while
calculators are allowed on many standardized tests, the TI-92 was not due to the
QWERTY layout of its keyboard. Additionally, some people found the TI-92 unwieldy and overly large. The TI-89 is significantly smaller—about the same size as most other graphing calculators. It has a flash ROM, a feature present on the TI-92 Plus but not on the original TI-92.
User features The major advantage of the TI-89 over other TI calculators is its built-in
computer algebra system, or CAS. The calculator can evaluate and simplify algebraic expressions symbolically. For example, entering x^2-4x+4 returns x^2-4x+4. The answer is "
prettyprinted" by default; that is, displayed as it would be written by hand (e.g. the aforementioned x^2-4x+4 rather than x^2-4x+4). The TI-89's abilities include: • Algebraic factoring of expressions, including
partial fraction decomposition. • Algebraic simplification; for example, the CAS can combine multiple terms into one fraction by finding a common
denominator. • Evaluation of trigonometric expressions to exact values. For example, sin(60°) returns \frac{\sqrt{3}}{2} instead of 0.86603. • Solving equations for a certain variable. The CAS can solve for one variable in terms of others; it can also solve systems of equations. For equations such as quadratics where there are multiple solutions, it returns all of them. Equations with infinitely many solutions are solved by introducing arbitrary constants: solve(tan(x+2)=0,x) returns x=2.(90.@n1-1), with the @n1 representing any integer. • Symbolic and numeric
differentiation and
integration.
Derivatives and
definite integrals are evaluated exactly when possible, and approximately otherwise. • Calculate
greatest common divisor (gcd) and
least common multiple (lcm) •
Probability theory:
factorial,
combination,
permutation,
binomial distribution,
normal distribution • PrettyPrint (like equation editor and
LaTeX) • These
mathematical constants are shown as symbols \pi, e, i and \infty • Draw 2D and 3D
graph • Calculate
limit of a function, including infinite limits and limits from one direction •
Vector calculation •
Matrix calculation • Calculate
series (summation or infinite product) • Calculate
chi squared test • Calculate
complex numbers • Factoring
polynomial: factor(polynomial) or cfactor(polynomial) • Solve
equation: solve(equation,x) or csolve(equation,x) • Solve first or second order
differential equation: deSolve(differential equation,x,y) • Multiply and divide
SI Units: underscore _ "diamond" "MODE" • A number of
regressions: • LinReg • QuadReg • CubicReg • QuartReg • ExpReg • LnReg • PowerReg • Logistic • SinReg In addition to the standard two-dimensional
function plots, it can also produce graphs of
parametric equations,
polar equations, sequence plots,
differential equation fields, and three-dimensional (two independent variable) functions.
Programming The TI-89 is directly programmable in a language called
TI-BASIC 89, TI's derivative of
BASIC for calculators. With the use of a
PC, it is also possible to develop more complex programs in Motorola 68000
assembly language or
C,
translate them to machine language, and copy them to the calculator. Two software development kits for C programming are available; one is TI Flash Studio, the official TI
SDK, and the other is TIGCC, a third-party SDK based on
GCC. In addition, there is a third party flash application called GTC that allows the writing and compilation of C programs directly on the calculator. It is built on TIGCC, with some modifications. Numerous BASIC extensions are also present, the most notable of which is NewProg. Since the TI-89's release in 1998, thousands of programs for
math,
science, or entertainment have been developed. Many video games have also been developed. Many are generic clones of
Tetris,
Minesweeper, and other classic games, but some programs are more advanced: for example, a
ZX Spectrum emulator, a
chess-playing program, a symbolic circuit simulator, and a clone of ''
Link's Awakening''. Some of the most popular and well-known games are
Phoenix,
Drugwars, and
Snake. Many calculator games and other useful programs can be found on TI-program sharing sites. Ticalc.org is a major one that offers thousands of calculator programs.
Hardware versions There are four hardware versions of the TI-89. These versions are normally referred to as HW1, HW2, HW3, and HW4 (released in May 2006). Entering the key sequence
[F1] [A] displays the hardware version. Older versions (before HW2) don't display anything about the hardware version in the about menu. The differences in the hardware versions are not well documented by Texas Instruments. HW1 and HW2 correspond to the original TI-89; HW3 and HW4 are only present in the TI-89 Titanium. The most significant difference between HW1 and HW2 is in the way the calculator handles the display. In HW1 calculators there is a video buffer that stores all of the information that should be displayed on the screen, and every time the screen is refreshed the calculator accesses this buffer and flushes it to the display (
direct memory access). In HW2 and later calculators, a region of memory is directly aliased to the display controller (
memory-mapped I/O). This allows for slightly faster memory access, as the HW1's DMA controller used about 10% of the bus bandwidth. However, it interferes with a trick some programs use to implement
grayscale graphics by rapidly switching between two or more displays (page-flipping). On the HW1, the DMA controller's base address can be changed (a single write into a
memory-mapped hardware register) and the screen will automatically use a new section of memory at the beginning of the next frame. In HW2, the new page must be written to the screen by software. The effect of this is to cause increased flickering in grayscale mode, enough to make the 7-level grayscale supported on the HW1 unusable (although 4-level grayscale works on both calculators). HW2 calculators are slightly faster because TI increased the nominal speed of the processor from 10 MHz to 12 MHz. It is believed that TI increased the speed of HW4 calculators to 16 MHz, though many users disagree about this finding. The measured statistics are closer to 14 MHz. Another difference between HW1 and HW2 calculators is assembly program size limitations. The size limitation on HW2 calculators has varied with the AMS version of the calculator. As of AMS 2.09 the limit is 24k. Some earlier versions limited assembly programs to 8k, and the earliest AMS versions had no limit. The latest AMS version has a 64kb limit. HW1 calculators have no hardware to enforce the limits, so it is easy to bypass them in software. There are
unofficial patches and kernels that can be installed on HW2 calculators to remove the limitations. == TI-89 Titanium ==