Atari MMU

The Atari MMU is a custom MMU 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.

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

References

MMU

MMU may refer to:

Atari

Atari is a corporate and brand name owned by several entities since its inception in 1972, currently by Atari Interactive, a subsidiary of the French publisher Atari, SA (ASA). The original Atari, Inc. founded 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, the original Atari Inc. was split due to its role in the video game crash of 1983, and the arcade division was turned into 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 rights to the original 1972–1984 arcade hardware properties. The Atari Consumer Electronics Division properties were in turn sold to Jack Tramiel's Tramel Technology Ltd., which then renamed itself to Atari Corporation. In 1996, Atari Corporation reverse-merged with disk-drive manufacturer JT Storage (JTS), becoming a division within the company.

Leonardo DiCaprio

Leonardo Wilhelm DiCaprio (/dᵻˈkæpri.oʊ/; born November 11, 1974) is an American actor and film producer. He has been nominated for numerous awards, and has won three Golden Globe Awards. DiCaprio began his career by appearing in television commercials, after which he had recurring roles in TV series such as the soap opera Santa Barbara and the sitcom Growing Pains in the early 1990s. He began his film career by starring as Josh in Critters 3 before starring in the film adaptation of the memoir This Boy's Life (1993) alongside Robert De Niro. DiCaprio was praised for his supporting role in the drama What's Eating Gilbert Grape (1993), and gained public recognition with leading roles in the drama The Basketball Diaries (1995) and the romantic drama Romeo + Juliet (1996), before achieving international fame with James Cameron's epic romance Titanic (1997), which became the highest-grossing film to that point.

Since the 2000s, DiCaprio has received critical acclaim for his work in a wide range of film genres. His subsequent films include The Man in the Iron Mask (1998), the biographical crime drama Catch Me If You Can (2002) and the epic historical drama Gangs of New York (2002) which also marked his first of many collaborations with director Martin Scorsese. DiCaprio was also acclaimed for his performances in the political war thriller Blood Diamond (2006), the neo-noir crime drama The Departed (2006), the espionage thriller Body of Lies (2008), the drama Revolutionary Road (2008), the psychological thriller Shutter Island (2010), the science fiction thriller Inception (2010), the biographical film J. Edgar (2011), the western Django Unchained (2012), and the period drama The Great Gatsby (2013).

Atari (disambiguation)

Atari could refer to: