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TK82C
TK82C was a Sinclair ZX81 clone made by Microdigital Eletrônica Ltda., a computer company located in Brazil. General information The TK82C had the Zilog Z80A processor running at 3.25 MHz, 2 KB SRAM and 8 KB of EPROM with the BASIC interpreter. The keyboard was made of layers of conductive (membrane) material and followed the Sinclair pattern. The video output was sent via a RF modulator to a TV set tuned at VHF channel 3, and it featured black characters on a white background. The maximum resolution was 64 x 44 pixels black and white, for graphic plotting. There were some special characters (shade patterns) useful for games and basic images. The TK82C included the SLOW function, which permitted the video be shown during the processing (the prior version, TK82, a Sinclair ZX80 clone, ran only in fast mode, so the image was not shown during its processing). In reality, the SLOW function was done by an add-on board that was factory-mounted over the main board. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microdigital Eletronica
Microdigital Eletrônica Ltda. was an influential Brazilian computer company in the 1980s, based in São Paulo. History Established in 1981 by the brothers George and Tomas Kovari (whose initials were the TK of the domestic computers line made by the company), its first product was the ''TK80'', a clone of the British microcomputer Sinclair ZX80. The company reached its height around 1985, with the launching of the TK90X (clone of the ZX Spectrum) and the ''TK-2000 II'', a personal computer partially compatible (at Applesoft BASIC level) with the Apple II+. At this time, it had approximately 400 employees in three plants (two in São Paulo and one in the Zona Franca de Manaus) and more than 700 peddlers spread for all Brazil. Although the logo of the company is identical to the earlier Microdigital Ltd of the United Kingdom the company is not related. Line of products A not extensive list of Microdigital's products: Home computers * TK80 (1981) * TK82 (1981) * TK82C (198 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TK85
The TK85 was a ZX81 clone made by Microdigital Eletrônica, a computer company located in Brazil. It came with 16 or 48 KB RAM, and had a ZX Spectrum–style case, similar to a ''Timex Sinclair 1500''. Unlike the ZX81, the TK85 used discrete logic circuits instead of a ULA, and during manufacture, several chips were scraped so that competitors couldn't copy the circuit. The circuit board had space for a AY-3-8912 The AY-3-8910 is a 3-voice programmable sound generator (PSG) designed by General Instrument in 1978, initially for use with their 16-bit CP1610 or one of the PIC1650 series of 8-bit microcomputers. The AY-3-8910 and its variants were used i ... sound generator chip (compatible with the ZonX-81 sound board), and although none came factory installed, it is possible to add the necessary circuits. The TK85 came with a copy of the 8K ZX81 floating point BASIC, and an additional 2K EPROM, mapped to addresses 8192-10240, containing machine code routines for us ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TK90X
The TK90X was the first Brazilian ZX Spectrum clone made in 1985 by Microdigital Electrônica, a company located in São Paulo, Brazil, that had manufactured some ZX81 clones (TK82C, TK83 and TK85) and ZX80 clones (TK80, TK82) before. Technical details The case was a little taller than the original Spectrum and the keyboard placement was equal to the original keyboard, except for some additional commands that did not exist in the Spectrums (for characters defined by the user — UDG — in the place of the 'Pound' symbol, and the 'Trace' function in BASIC), and included specific Portuguese and Spanish characters such as ç and ñ, as well as accented vowels. The two versions were the 16 KB and 48 KB of RAM. They contained the same processor (Z80A), running at 3.58 MHz and a ROM chip, some RAM chips (old dynamic RAMs 4116 and 4416). Microdigital reverse engineered a CMOS integrated circuit (IC) with similar functionality to the original Bipolar IC ULA from Sin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Uncommitted Logic Array
A gate array is an approach to the design and manufacture of application-specific integrated circuits (ASICs) using a prefabricated chip with components that are later interconnected into logic devices (e.g. NAND gates, flip-flops, etc.) according to a custom order by adding metal interconnect layers in the factory. It was popular during upheaval in semiconductor industry in 80s and its usage declined by end of 90s. Similar technologies have also been employed to design and manufacture analog, analog-digital, and structured arrays, but, in general, these are not called gate arrays. Gate arrays have also been known as ''uncommitted logic arrays'' (''ULAs''), which also offered linear circuit functions, and ''semi-custom chips''. History Development Gate arrays had several concurrent development paths. Ferranti in the UK pioneered commercializing bipolar ULA technology, offering circuits of "100 to 10,000 gates and above" by 1983. The company's early lead in semi-custom chips, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Copier
A photocopier (also called copier or copy machine, and formerly Xerox machine, the generic trademark) is a machine that makes copies of documents and other visual images onto paper or plastic film quickly and cheaply. Most modern photocopiers use a technology called ''xerography'', a dry process that uses electrostatic charges on a light-sensitive photoreceptor to first attract and then transfer toner particles (a powder) onto paper in the form of an image. The toner is then fused onto the paper using heat, pressure, or a combination of both. Copiers can also use other technologies, such as inkjet, but xerography is standard for office copying. Commercial xerographic office photocopying was introduced by Xerox in 1959, and it gradually replaced copies made by Verifax, Photostat, carbon paper, mimeograph machines, and other duplicating machines. Photocopying is widely used in the business, education, and government sectors. While there have been predictions that photocopiers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ZX Spectrum
The ZX Spectrum () is an 8-bit computing, 8-bit home computer that was developed by Sinclair Research. It was released in the United Kingdom on 23 April 1982, and became Britain's best-selling microcomputer. Referred to during development as the ''ZX81 Colour'' and ''ZX82'', it was launched as the ''ZX Spectrum'' to highlight the machine's colour display, which differed from the black and white display of its predecessor, the ZX81. The Spectrum was released as six different models, ranging from the entry level with 16 Kilobyte, KB RAM released in 1982 to the ZX Spectrum +3 with 128 KB RAM and built in floppy disk drive in 1987; altogether they sold over 5 million units worldwide (not counting List of ZX Spectrum clones, unofficial clones). The Spectrum was among the first home computers in the United Kingdom aimed at a mainstream audience, and it thus had similar significance to the Commodore 64 in the US and the Thomson MO5 in France. The introduction of the ZX Spect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TK95
The TK 95 microcomputer was a 1986 ZX Spectrum clone by Microdigital Eletrônica, a company located at São Paulo, Brazil. It was an evolution of the TK90X introduced the previous year. The case was redesigned (copied from the Commodore Plus/4) and the keyboard was said to be "semi-professional" (according to the Brazilian manufacturer), with the some additional Sinclair BASIC commands that did not exist in the ZX Spectrums (for user defined charactersUDG), and better compatibility with the original ZX Spectrum (compared to the TK90X). Like the Spectrum, the machine had 48 kilobytes of RAM. Inside, the same processor: Z80A running at 3.58 MHz, a 16 KB ROM chip and some RAM chips (old dynamic rams 4116 and 4416). Microdigital did some reverse engineering to develop a chip with the functions of the original ULA from Sinclair/Ferranti. The modulator was tuned to VHF channel 3 and the TV system was PAL-M (60 Hz). The cassette interface ran at a faster speed than the Spect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Copyright Violation
Copyright infringement (at times referred to as piracy) is the use of works protected by copyright without permission for a usage where such permission is required, thereby infringing certain exclusive rights granted to the copyright holder, such as the right to reproduce, distribute, display or perform the protected work, or to make derivative works. The copyright holder is typically the work's creator, or a publisher or other business to whom copyright has been assigned. Copyright holders routinely invoke legal and technological measures to prevent and penalize copyright infringement. Copyright infringement disputes are usually resolved through direct negotiation, a notice and take down process, or litigation in civil court. Egregious or large-scale commercial infringement, especially when it involves counterfeiting, is sometimes prosecuted via the criminal justice system. Shifting public expectations, advances in digital technology and the increasing reach of the Internet hav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sinclair Research
Sinclair Research Ltd is a British consumer electronics company founded by Clive Sinclair in Cambridge. It was originally incorporated in 1973 as Westminster Mail Order Ltd, renamed Sinclair Instrument Ltd, then Science of Cambridge Ltd, then Sinclair Computers Ltd, and finally Sinclair Research Ltd. It remained dormant until 1976, when it was activated with the intention of continuing Sinclair's commercial work from his earlier company Sinclair Radionics, and adopted the name Sinclair Research in 1981. In 1980, Clive Sinclair entered the home computer market with the ZX80 at £99.95, at that time the cheapest personal computer for sale in the United Kingdom. In 1982 the ZX Spectrum was released, becoming the UK's best selling computer, and competing aggressively against Commodore and Amstrad. At the height of its success, and largely inspired by the Japanese Fifth Generation Computer program, the company established the "MetaLab" research centre at Milton Hall near Cambrid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ZX Printer
The Sinclair ZX Printer is a spark printer which was produced by Sinclair Research for its ZX81 home computer. It was launched in 1981, with a recommended retail price of £49.95. The ZX Printer used special wide black paper which was supplied coated with a thin layer of aluminium. To mark the paper, one of the printer's two styluses passed a current through a small area of the aluminium layer, causing the aluminium to evaporate and reveal the black under-surface. The printer's horizontal resolution was the same as the ZX81's video display, i.e. 256 dots (pixels) or 32 characters (using the standard character definition). The ZX Printer was never intended for word processing purposes, instead being aimed at users who wanted to obtain program listings for reference purposes. The ZX Printer was also compatible with the earlier ZX80 computer (when fitted with the 8kB ROM upgrade) and the later ZX Spectrum, and plugged directly into the expansion bus connector via a short cable. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atari 2600
The Atari 2600, initially branded as the Atari Video Computer System (Atari VCS) from its release until November 1982, is a home video game console developed and produced by Atari, Inc. Released in September 1977, it popularized microprocessor-based hardware and games stored on swappable ROM cartridges, a format first used with the Fairchild Channel F in 1976. The VCS was bundled with two joystick controllers, a conjoined pair of paddle controllers, and a game cartridgeinitially '' Combat'' and later '' Pac-Man''. Atari was successful at creating arcade video games, but their development cost and limited lifespan drove CEO Nolan Bushnell to seek a programmable home system. The first inexpensive microprocessors from MOS Technology in late 1975 made this feasible. The console was prototyped as codename Stella by Atari subsidiary Cyan Engineering. Lacking funding to complete the project, Bushnell sold Atari to Warner Communications in 1976. The Atari VCS launched in 1977 with n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DRAM
Dynamic random-access memory (dynamic RAM or DRAM) is a type of random-access semiconductor memory that stores each bit of data in a memory cell, usually consisting of a tiny capacitor and a transistor, both typically based on metal-oxide-semiconductor (MOS) technology. While most DRAM memory cell designs use a capacitor and transistor, some only use two transistors. In the designs where a capacitor is used, the capacitor can either be charged or discharged; these two states are taken to represent the two values of a bit, conventionally called 0 and 1. The electric charge on the capacitors gradually leaks away; without intervention the data on the capacitor would soon be lost. To prevent this, DRAM requires an external ''memory refresh'' circuit which periodically rewrites the data in the capacitors, restoring them to their original charge. This refresh process is the defining characteristic of dynamic random-access memory, in contrast to static random-access memory (SRA ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
