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TK 90X
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 ... [...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] |
Read-only Memory
Read-only memory (ROM) is a type of non-volatile memory used in computers and other electronic devices. Data stored in ROM cannot be electronically modified after the manufacture of the memory device. Read-only memory is useful for storing software that is rarely changed during the life of the system, also known as firmware. Software applications (like video games) for programmable devices can be distributed as plug-in cartridges containing ROM. Strictly speaking, ''read-only memory'' refers to memory that is hard-wired, such as diode matrix or a mask ROM integrated circuit (IC), which cannot be electronically changed after manufacture. Although discrete circuits can be altered in principle, through the addition of bodge wires and/or the removal or replacement of components, ICs cannot. Correction of errors, or updates to the software, require new devices to be manufactured and to replace the installed device. Floating-gate ROM semiconductor memory in the form of erasab ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microdigital Eletrônica
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] |
Mikie
''Mikie'', known as in Japan, is an arcade video game developed and released by Konami in 1984. The object of the game is to guide a student named Mikie around the school locations to collect hearts which make up a letter from his girlfriend while being chased by members of the school staff. In Japan, the game's setting was changed to an office in order to avoid controversy, while the original version of the game was released internationally. Centuri distributed the game in North America. Gameplay The game starts at the classroom where Toru Mikie (美紀 徹, Miki Tōru) gets out of his seat for the player to begin the game. Mikie must bump the students out of their seats to collect the hearts they're sitting on, while simultaneously avoiding the classroom teacher. Once all hearts are collected by the player he is allowed to leave the room and enter the school corridor. The school corridor is where Mikie will be chased by the janitor and his classroom teacher, who follows him o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Commodore Plus4
The Commodore Plus/4 is a home computer released by Commodore International in 1984. The "Plus/4" name refers to the four-application ROM resident office suite (word processor, spreadsheet, database, and graphing); it was billed as "the productivity computer with software built-in." Internally, the Plus/4 shared the same basic architecture as the lower-end Commodore 16 and 116 models, and was able to use software and peripherals designed for them. The Plus/4 was incompatible with the Commodore 64's software and some of its hardware. Although the Commodore 64 was more established, the Plus/4 was aimed at the more business oriented part of the personal computer market. History In the early 1980s, Commodore found itself engaged in a price war in the home computer market. Companies like Texas Instruments and Timex Corporation were releasing computers that undercut the price of Commodore's PET line. Commodore's MOS Technology division had designed a video chip but coul ... [...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] |
NTSC
The first American standard for analog television broadcast was developed by National Television System Committee (NTSC)National Television System Committee (1951–1953), Report and Reports of Panel No. 11, 11-A, 12–19, with Some supplementary references cited in the Reports, and the Petition for adoption of transmission standards for color television before the Federal Communications Commission, n.p., 1953], 17 v. illus., diagrs., tables. 28 cm. LC Control No.:5402138Library of Congress Online Catalog/ref> in 1941. In 1961, it was assigned the designation CCIR System M, System M. In 1953, a second NTSC standard was adopted, which allowed for color television broadcast compatible with the existing stock of black-and-white receivers. It is one of three major color formats for analog television, the others being PAL and SECAM. NTSC color is usually associated with the System M. The only other broadcast television system to use NTSC color was the System J. Since the introdu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PAL-N
Phase Alternating Line (PAL) is a colour encoding system for analogue television. It was one of three major analogue colour television standards, the others being NTSC and SECAM. In most countries it was broadcast at 625 lines, 50 fields (25 frames) per second, and associated with CCIR analogue broadcast television systems B, D, G, H, I or K. The articles on analog broadcast television systems further describe frame rates, image resolution, and audio modulation. PAL video is composite video because luminance (luma, monochrome image) and chrominance (chroma, colour applied to the monochrome image) are transmitted together as one signal. A latter evolution of the standard, PALplus, added support for widescreen broadcasts with no loss of vertical resolution, while retaining compatibility with existing sets. Almost all of the countries using PAL are currently in the process of conversion, or have already converted transmission standards to DVB, ISDB or DTMB. Due to the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PAL-M
PAL-M is the analogue TV system used in Brazil since 19 February 1972. At that time, Brazil was the first South American country to broadcast in colour. Colour TV broadcast began on 19 February 1972, when the TV networks Globo and Bandeirantes transmitted the Caxias do Sul Grape Festival. Transition from black and white to colour, however, was not complete until 1978. Two years later, in 1980, colour broadcast nationwide in Brazil was commonplace. It is unique among analogue TV systems in that it combines the 525-line 30 frames-per-second System M with the PAL colour encoding system (using very nearly the NTSC colour subcarrier frequency), unlike all other countries which pair PAL with 625-line systems and NTSC with 525-line systems. Origins NTSC being the "natural" choice for countries with monochrome standard M, the choice of a different colour system poses problems of incompatibility with available hardware and the need to develop new television sets and production hardwa ... [...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] |
Bipolar Junction Transistor
A bipolar junction transistor (BJT) is a type of transistor that uses both electrons and electron holes as charge carriers. In contrast, a unipolar transistor, such as a field-effect transistor, uses only one kind of charge carrier. A bipolar transistor allows a small current injected at one of its terminals to control a much larger current flowing between the terminals, making the device capable of amplification or switching. BJTs use two p–n junctions between two semiconductor types, n-type and p-type, which are regions in a single crystal of material. The junctions can be made in several different ways, such as changing the doping of the semiconductor material as it is grown, by depositing metal pellets to form alloy junctions, or by such methods as diffusion of n-type and p-type doping substances into the crystal. The superior predictability and performance of junction transistors quickly displaced the original point-contact transistor. Diffused transistors, along wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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