TI-85
Encyclopedia
The TI-85 was a graphing calculator
made by Texas Instruments
based around the Zilog Z80
microprocessor
. Designed in 1992 as TI's second graphing calculator (the first was the TI-81
), it has since been replaced by the TI-86
, which has also been discontinued.
The TI-85 was significantly more powerful than the TI-81
, as it was designed as a calculator primarily for use in engineering and calculus courses. Texas Instruments had included a version of BASIC
on the device to allow programming
. Each calculator came with a cable to connect calculators (simply a three-conductor cable with 2.5 mm jack plugs on each end). Another cable known as the TI-Graph Link was also sold, along with appropriate software, to connect the calculator to a personal computer
. These cables made it possible to save programs and make backup
s.
programs. These programs could run much faster than their BASIC counterparts, and could be much more efficient in terms of memory usage. This development made the TI-85 the first TI graphing calculator that could execute assembly programs.
Programs written in assembly would be stored as string
expressions and accessed via the CUSTOM menu. Games such as Tetris
and Boulder Dash
are available, as are programs with more practical uses, such as versions of the periodic table
. The use of these programs was limited by the scarce RAM
memory available on the TI-85. Total memory capacity was about 32 kilobyte
s, with 28226 byte
s available for use.
The assembly language shell
ZShell is also available for the TI-85, with the most famous version still unreleased on Magnus Hagander's TI-85 http://www.ticalc.org/about/staff/mha.html.
Probably in response to the widespread use of assembly programs, TI officially introduced assembly access in later models, such as the TI-83 and TI-86
, along with expanded memory. The TI-86 is very similar to the TI-85, sharing the same display resolution
(128×64), processor, and processor speed (6 MHz).
RAM
ROM
Display
Link capability
Power
Programming language
(s)
Graphing calculator
A graphing calculator typically refers to a class of handheld calculators that are capable of plotting graphs, solving simultaneous equations, and performing numerous other tasks with variables...
made by Texas Instruments
Texas Instruments
Texas Instruments Inc. , widely known as TI, is an American company based in Dallas, Texas, United States, which develops and commercializes semiconductor and computer technology...
based around the Zilog Z80
Zilog Z80
The Zilog Z80 is an 8-bit microprocessor designed by Zilog and sold from July 1976 onwards. It was widely used both in desktop and embedded computer designs as well as for military purposes...
microprocessor
Microprocessor
A microprocessor incorporates the functions of a computer's central processing unit on a single integrated circuit, or at most a few integrated circuits. It is a multipurpose, programmable device that accepts digital data as input, processes it according to instructions stored in its memory, and...
. Designed in 1992 as TI's second graphing calculator (the first was the TI-81
TI-81
The TI-81 is the first graphing calculator made by Texas Instruments. It was designed in 1990 for use in algebra and precalculus courses. Since its original release, it has been superseded several times by newer calculators - the TI-82, the TI-83, the TI-83 Plus, TI-83 Plus Silver Edition, the...
), it has since been replaced by the TI-86
TI-86
The TI-86 is a programmable graphing calculator introduced in 1997 and produced by Texas Instruments. The TI-86 uses the Zilog Z80 microprocessor. It is partially backwards-compatible with its predecessor, the TI-85....
, which has also been discontinued.
The TI-85 was significantly more powerful than the TI-81
TI-81
The TI-81 is the first graphing calculator made by Texas Instruments. It was designed in 1990 for use in algebra and precalculus courses. Since its original release, it has been superseded several times by newer calculators - the TI-82, the TI-83, the TI-83 Plus, TI-83 Plus Silver Edition, the...
, as it was designed as a calculator primarily for use in engineering and calculus courses. Texas Instruments had included a version of BASIC
BASIC
BASIC is a family of general-purpose, high-level programming languages whose design philosophy emphasizes ease of use - the name is an acronym from Beginner's All-purpose Symbolic Instruction Code....
on the device to allow programming
Computer programming
Computer programming is the process of designing, writing, testing, debugging, and maintaining the source code of computer programs. This source code is written in one or more programming languages. The purpose of programming is to create a program that performs specific operations or exhibits a...
. Each calculator came with a cable to connect calculators (simply a three-conductor cable with 2.5 mm jack plugs on each end). Another cable known as the TI-Graph Link was also sold, along with appropriate software, to connect the calculator to a personal computer
Personal computer
A personal computer is any general-purpose computer whose size, capabilities, and original sales price make it useful for individuals, and which is intended to be operated directly by an end-user with no intervening computer operator...
. These cables made it possible to save programs and make backup
Backup
In information technology, a backup or the process of backing up is making copies of data which may be used to restore the original after a data loss event. The verb form is back up in two words, whereas the noun is backup....
s.
Assembly programs
Enthusiasts analyzed memory backups and discovered that entries in the calculator's CUSTOM menu pointed at specific memory locations. With this knowledge, a hack was devised where a special string could be inserted into the backup at the proper location to allow the calculator to execute assembly languageAssembly language
An assembly language is a low-level programming language for computers, microprocessors, microcontrollers, and other programmable devices. It implements a symbolic representation of the machine codes and other constants needed to program a given CPU architecture...
programs. These programs could run much faster than their BASIC counterparts, and could be much more efficient in terms of memory usage. This development made the TI-85 the first TI graphing calculator that could execute assembly programs.
Programs written in assembly would be stored as string
String (computer science)
In formal languages, which are used in mathematical logic and theoretical computer science, a string is a finite sequence of symbols that are chosen from a set or alphabet....
expressions and accessed via the CUSTOM menu. Games such as Tetris
Tetris
Tetris is a puzzle video game originally designed and programmed by Alexey Pajitnov in the Soviet Union. It was released on June 6, 1984, while he was working for the Dorodnicyn Computing Centre of the Academy of Science of the USSR in Moscow, Russian Soviet Federative Socialist Republic...
and Boulder Dash
Boulder Dash
Boulder Dash, originally released in 1984 for Atari 8-bit computers, is a series of computer games released for the Apple II, MSX, ZX Spectrum, Commodore 64, and ColecoVision home computers, and later ported to the NES, BBC Micro and Acorn Electron, PC, Amstrad CPC, Amiga and many other platforms...
are available, as are programs with more practical uses, such as versions of the periodic table
Periodic table
The periodic table of the chemical elements is a tabular display of the 118 known chemical elements organized by selected properties of their atomic structures. Elements are presented by increasing atomic number, the number of protons in an atom's atomic nucleus...
. The use of these programs was limited by the scarce RAM
Random-access memory
Random access memory is a form of computer data storage. Today, it takes the form of integrated circuits that allow stored data to be accessed in any order with a worst case performance of constant time. Strictly speaking, modern types of DRAM are therefore not random access, as data is read in...
memory available on the TI-85. Total memory capacity was about 32 kilobyte
Kilobyte
The kilobyte is a multiple of the unit byte for digital information. Although the prefix kilo- means 1000, the term kilobyte and symbol KB have historically been used to refer to either 1024 bytes or 1000 bytes, dependent upon context, in the fields of computer science and information...
s, with 28226 byte
Byte
The byte is a unit of digital information in computing and telecommunications that most commonly consists of eight bits. Historically, a byte was the number of bits used to encode a single character of text in a computer and for this reason it is the basic addressable element in many computer...
s available for use.
The assembly language shell
Assembly shell (graphing calculator)
On graphing calculators, an assembly shell is a program that is used to run programs written in the calculator's native machine code rather than the calculator's standard high-level programming language...
ZShell is also available for the TI-85, with the most famous version still unreleased on Magnus Hagander's TI-85 http://www.ticalc.org/about/staff/mha.html.
Probably in response to the widespread use of assembly programs, TI officially introduced assembly access in later models, such as the TI-83 and TI-86
TI-86
The TI-86 is a programmable graphing calculator introduced in 1997 and produced by Texas Instruments. The TI-86 uses the Zilog Z80 microprocessor. It is partially backwards-compatible with its predecessor, the TI-85....
, along with expanded memory. The TI-86 is very similar to the TI-85, sharing the same display resolution
Display resolution
The display resolution of a digital television or display device is the number of distinct pixels in each dimension that can be displayed. It can be an ambiguous term especially as the displayed resolution is controlled by all different factors in cathode ray tube , flat panel or projection...
(128×64), processor, and processor speed (6 MHz).
Technical specifications
CPUCentral processing unit
The central processing unit is the portion of a computer system that carries out the instructions of a computer program, to perform the basic arithmetical, logical, and input/output operations of the system. The CPU plays a role somewhat analogous to the brain in the computer. The term has been in...
- Zilog Z80Zilog Z80The Zilog Z80 is an 8-bit microprocessor designed by Zilog and sold from July 1976 onwards. It was widely used both in desktop and embedded computer designs as well as for military purposes...
CPU, 6 MHz
RAM
Random-access memory
Random access memory is a form of computer data storage. Today, it takes the form of integrated circuits that allow stored data to be accessed in any order with a worst case performance of constant time. Strictly speaking, modern types of DRAM are therefore not random access, as data is read in...
- 32 KBKilobyteThe kilobyte is a multiple of the unit byte for digital information. Although the prefix kilo- means 1000, the term kilobyte and symbol KB have historically been used to refer to either 1024 bytes or 1000 bytes, dependent upon context, in the fields of computer science and information...
, (28 KB user-available)
ROM
Read-only memory
Read-only memory is a class of storage medium used in computers and other electronic devices. Data stored in ROM cannot be modified, or can be modified only slowly or with difficulty, so it is mainly used to distribute firmware .In its strictest sense, ROM refers only...
- 128 KB non-upgradeable
Display
Electronic visual display
An electronic visual display is display technology which incorporates flat panel displays, performs as a video display, output device for presentation of images transmitted electronically, for visual reception, without producing a permanent record....
- Text: 21×8 characters
- Graphics: 128×64 pixels, monochrome
Link capability
- 2.5 mm I/O port
Power
Electric power
Electric power is the rate at which electric energy is transferred by an electric circuit. The SI unit of power is the watt.-Circuits:Electric power, like mechanical power, is represented by the letter P in electrical equations...
- 4×AAAAAA batteryA triple A or AAA battery is a standard size of dry cell battery commonly used in portable electronic devices. A carbon-zinc battery in this size is designated by IEC as "R03", by ANSI C18.1 as "24", by old JIS standard as "UM 4", and by other manufacturer and national standard designations that...
, 1×CR1616 or CR1620
Programming language
Programming language
A programming language is an artificial language designed to communicate instructions to a machine, particularly a computer. Programming languages can be used to create programs that control the behavior of a machine and/or to express algorithms precisely....
(s)
- TI-BASICTI-BASICTI-BASIC is the unofficial name of a BASIC-like language built into Texas Instruments 's graphing calculators, including the TI-83 series, TI-84 Plus series, TI-89 series, TI-92 series , TI-73, and TI-Nspire...
, Z80 AssemblyAssembly languageAn assembly language is a low-level programming language for computers, microprocessors, microcontrollers, and other programmable devices. It implements a symbolic representation of the machine codes and other constants needed to program a given CPU architecture...
(hacked)
External links
- TI-85 Guidebook (PDF)
- ticalc.org – The largest archive of TI programs available.
- CalcG.org - Very organized and large archive of games and programs.
- TI-85 Graphical Demo - An interesting graphical demo programmed for a TI-85.