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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] |
The Atari FREDDIE
''The'' () is a grammatical article in English, denoting persons or things that are already or about to be mentioned, under discussion, implied or otherwise presumed familiar to listeners, readers, or speakers. It is the definite article in English. ''The'' is the most frequently used word in the English language; studies and analyses of texts have found it to account for seven percent of all printed English-language words. It is derived from gendered articles in Old English which combined in Middle English and now has a single form used with nouns of any gender. The word can be used with both singular and plural nouns, and with a noun that starts with any letter. This is different from many other languages, which have different forms of the definite article for different genders or numbers. Pronunciation In most dialects, "the" is pronounced as (with the voiced dental fricative followed by a schwa) when followed by a consonant sound, and as (homophone of the archaic pr ... [...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] |
Atari 8-bit Family
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 CPU A central processing unit (CPU), also called a central processor, main processor or just processor, is the electronic circuitry that executes instructions comprising a computer program. The CPU performs basic arithmetic, logic, controlling, and ... 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, wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Random Access Memory
Random-access memory (RAM; ) is a form of computer memory that can be read and changed in any order, typically used to store working data and machine code. A random-access memory device allows data items to be read or written in almost the same amount of time irrespective of the physical location of data inside the memory, in contrast with other direct-access data storage media (such as hard disks, CD-RWs, DVD-RWs and the older magnetic tapes and drum memory), where the time required to read and write data items varies significantly depending on their physical locations on the recording medium, due to mechanical limitations such as media rotation speeds and arm movement. RAM contains multiplexing and demultiplexing circuitry, to connect the data lines to the addressed storage for reading or writing the entry. Usually more than one bit of storage is accessed by the same address, and RAM devices often have multiple data lines and are said to be "8-bit" or "16-bit", etc. devices ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multiplexer
In electronics, a multiplexer (or mux; spelled sometimes as multiplexor), also known as a data selector, is a device that selects between several analog or digital input signals and forwards the selected input to a single output line. The selection is directed by a separate set of digital inputs known as select lines. A multiplexer of 2^n inputs has n select lines, which are used to select which input line to send to the output. A multiplexer makes it possible for several input signals to share one device or resource, for example, one analog-to-digital converter or one communications transmission medium, instead of having one device per input signal. Multiplexers can also be used to implement Boolean functions of multiple variables. Conversely, a demultiplexer (or demux) is a device taking a single input and selecting signals of the output of the compatible mux, which is connected to the single input, and a shared selection line. A multiplexer is often used with a compleme ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dynamic Random Access Memory
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 (S ... [...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] |
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] |
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