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Atari MMU
Atari MMU is a custom memory management unit chip for the Atari 8-bit computers. It enables access to the hardware registers on ANTIC, GTIA, POKEY and 6520 PIA. The later XL/XE MMU (C061618) also selects OS ROM, Atari BASIC ROM, self-test ROM and LEDs in the 1200XL. On the 128K 130XE the EMMU chip handles similar functionality. The user cannot directly manipulate the Atari MMU, but selects the various ROMS and memory via the memory-mapped hardware register known as PORTB (5401710 or D30116). Atari changed PORTB from an input port on the 400/800 machines to an output port on the XL/XE machines, leaving two joystick ports instead of four on the XL/XE machines. By setting and clearing specific bits in PORTB, the user can access either the ROMs or memory locations. No synchronization is required as the OS handles the access. The bit assignments for PORTB on the XL/XE machines are: Note: The 1200XL does not have BASIC built-in. See also * Atari FREDDIE FREDDIE is the name fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atari MMU Chip
Atari () is a brand name that has been owned by several entities since its inception in 1972. It is currently owned by French publisher Atari SA through a subsidiary named Atari Interactive. The original Atari, Inc., founded in Sunnyvale, California, in 1972 by Nolan Bushnell and Ted Dabney, was a pioneer in arcade games, home video game consoles and home computers. The company's products, such as ''Pong'' and the Atari 2600, helped define the electronic entertainment industry from the 1970s to the mid-1980s. In 1984, as a result of the video game crash of 1983, the home console and computer divisions of the original Atari Inc. were sold off, and the company was renamed Atari Games Inc. Atari Games received the rights to use the logo and brand name with appended text "Games" on arcade games, as well as the derivative coin-operated arcade rights to the original 1972–1984 arcade hardware properties. The Atari Consumer Electronics Division properties were in turn sold to Jack T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Memory Management Unit
A memory management unit (MMU), sometimes called paged memory management unit (PMMU), is a computer hardware unit having all memory references passed through itself, primarily performing the translation of virtual memory addresses to physical addresses. An MMU effectively performs virtual memory management, handling at the same time memory protection, cache control, bus arbitration and, in simpler computer architectures (especially 8-bit systems), bank switching. Overview Modern MMUs typically divide the virtual address space (the range of addresses used by the processor) into pages, each having a size which is a power of 2, usually a few kilobytes, but they may be much larger. The bottom bits of the address (the offset within a page) are left unchanged. The upper address bits are the virtual page numbers. Page table entries Most MMUs use an in-memory table of items called a " page table", containing one " page table entry" (PTE) per page, to map virtual page numb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atari 8-bit
The Atari 8-bit family is a series of 8-bit home computers introduced by Atari, Inc. in 1979 as the Atari 400 and Atari 800. The series was successively upgraded to Atari 1200XL , Atari 600XL, Atari 800XL, Atari 65XE, Atari 130XE, Atari 800XE, and Atari XEGS, the last discontinued in 1992. They differ primarily in packaging, each based on the MOS Technology 6502 central processing unit, CPU at and the same custom coprocessor chips. As the first home computer architecture with coprocessors, it has graphics and sound more advanced than most contemporary machines. Video games were a major draw, and first-person space combat simulator ''Star Raiders'' is considered the platform's killer app. The plug-and-play peripherals use the Atari SIO serial bus, with one developer eventually also co-patenting USB. While using the same internal technology, the Atari 800 was sold as a high-end model, while the 400 was more affordable. The 400 has a pressure-sensitive, spillproof membrane keyboar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ANTIC
Alphanumeric Television Interface Controller (ANTIC) is an LSI ASIC dedicated to generating 2D computer graphics to be shown on a television screen or computer display. Under the direction of Jay Miner, the chip was designed in 1977-1978 by Joe Decuir, Francois Michel, and Steve Smith for the Atari 8-bit family of home computers first released in 1979 and was patented by Atari, Inc. in 1981. ANTIC is also used in the 1982 Atari 5200 video game console, which shares most of the same hardware as the 8-bit computers. For every frame of video, ANTIC reads a program of instructions to define the playfield, or background graphics, then delivers a data stream to the companion CTIA or GTIA chip which adds color and overlays sprites (referred to as "Player/Missile graphics" by Atari). Each ANTIC instruction corresponds to either blank scan lines or one of 14 graphics modes used for a horizontal band of the display. The height of each band depends on the mode. A full program, or d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GTIA
Color Television Interface Adaptor (CTIA) and its successor Graphic Television Interface Adaptor (GTIA) are custom chips used in the Atari 8-bit family of computers and in the Atari 5200 home video game console. In these systems, a CTIA or GTIA chip works together with ANTIC to produce the video display. ANTIC generates the playfield graphics (text and bitmap) while CTIA/GTIA provides the color for the playfield and adds overlay objects known as player/missile graphics ( sprites). Under the direction of Jay Miner, the CTIA/GTIA chips were designed by George McLeod with technical assistance of Steve Smith. ''Color Television Interface Adaptor'' and ''Graphic Television Interface Adaptor'' are names of the chips as stated in the Atari field service manual. Various publications named the chips differently, sometimes using the alternative spelling ''Adapter'' or ''Graphics'', or claiming that the "C" in "CTIA" stands for Colleen/Candy and "G" in "GTIA" is for George. History 2600 a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
POKEY
POKEY, an acronym for Pot Keyboard Integrated Circuit, is a digital I/O chip designed by Doug Neubauer at Atari, Inc. for the Atari 8-bit family of home computers. It was first released with the Atari 400 and Atari 800 in 1979 and is included in all later models and the Atari 5200 console. POKEY combines functions for reading paddle controllers (potentiometers) and computer keyboards as well as sound generation and a source for pseduo-random numbers. It produces four voices of distinctive square wave audio, either as clear tones or modified with distortion settings. Neubauer also developed the Atari 8-bit killer application ''Star Raiders'' which makes use of POKEY features. POKEY chips are used for audio in many arcade video games of the 1980s including ''Centipede'', '' Missile Command'', '' Asteroids Deluxe'', and ''Gauntlet''. Some of Atari's arcade systems use multi-core versions with 2 or 4 POKEYs in a single package for more audio channels. The Atari 7800 console ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Operating System
An operating system (OS) is system software that manages computer hardware, software resources, and provides common daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), schedule tasks for efficient use of the system and may also include accounting software for cost allocation of Scheduling (computing), processor time, mass storage, printing, and other resources. For hardware functions such as input and output and memory allocation, the operating system acts as an intermediary between programs and the computer hardware, although the application code is usually executed directly by the hardware and frequently makes system calls to an OS function or is interrupted by it. Operating systems are found on many devices that contain a computer from cellular phones and video game consoles to web servers and supercomputers. The dominant general-purpose personal computer operating system is Microsoft Windows with a market share of aroun ... [...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 era ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atari BASIC
Atari BASIC is an interpreter for the BASIC programming language that shipped with the Atari 8-bit family of 6502-based home computers. Unlike most American BASICs of the home computer era, Atari BASIC is not a derivative of Microsoft BASIC and differs in significant ways. It includes keywords for Atari-specific features and lacks support for string arrays, for example. The language was distributed as an 8 KB ROM cartridge for use with the 1979 Atari 400 and 800 computers. Starting with the 600XL and 800XL in 1983, BASIC is built into the system. Despite the Atari 8-bit computers running at a higher speed than most of its contemporaries, several technical decisions placed Atari BASIC near the bottom in performance benchmarks. The original authors addressed most of these issues in a series of improved versions: BASIC A+ (1981), BASIC XL (1983), and BASIC XE (1985). A host of third-party interpreters and compilers like Turbo-Basic XL also appeared. The complete, anno ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atari FREDDIE
FREDDIE is the name for a 40-pin large scale integrated circuit found in later model Atari 8-bit computers. It is a RAM address multiplexer, used for DRAM access. Atari created this chip to replace several other chips to cut costs and to enhance CPU and ANTIC memory access. FREDDIE, combined with a C061618 MMU (XL/XE) and C025953 EMMU Emmu is a village in Lääneranna Parish, Pärnu County in southwestern Estonia Estonia, formally the Republic of Estonia, is a country by the Baltic Sea in Northern Europe. It is bordered to the north by the Gulf of Finland across fr ... (130XE) allows the CPU and ANTIC to access memory independently of each other. Originally designed for the cancelled 1400XL and 1450XLD, it was eventually used in the 800XLF (labelled "800XL," refers to European version), 65XE, 130XE, and XEGS. External linksatarimuseum.comFreddie MCU Engineering Data (PDF file)Freddie info and diagram {{compu-storage-stub FREDDIE, Atari ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
