Commodore  Amiga 2000
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Introduction

The Amiga 2000, or A2000, is a personal computer released by Commodore in March 1987. It was variant of the Amiga 1000 but quickly redesigned to share most of its electronic components with the contemporary Amiga 500 for cost reduction. Expansion capabilities include two 3.5" drive bays and one 5.25" bay that could be used by a 5.25" floppy drive , a hard drive, or CD-ROM.

The Amiga 2000 is the first Amiga model that allows expansion cards to be added internally. SCSI host adapters, memory cards, CPU cards, network cards, graphics cards, serial port cards, and PC compatibility cards were available, and multiple expansions can be used simultaneously without requiring an expansion cage like the Amiga 1000 does. Not only does the Amiga 2000 include five Zorro II card slots, the motherboard also has four PC ISA slots, two of which are in-line with Zorro II slots for use with the A2088 bridgeboard.

Motorola 68000 CPU Family

The Motorola 68000 is a 16/32-bit microprocessor that was first released in 1979. It was widely used in computers and other electronic devices during the 1980s and early 1990s. The 68000 was known for its advanced architecture, which included a 32-bit internal bus and a 24-bit address bus, allowing it to access up to 16 megabytes of memory. This made it more powerful than many other processors of its time, such as the Intel 8086 and Zilog Z80. It was also designed to be highly modular and expandable, with a large number of on-chip and off-chip peripherals.

Some of the most famous and successful computers that used the 68000 was the Commodore Amiga and the Atari ST, both of which were popular in the home and personal computer markets. Additionally, it was also used in workstations, such as the Sun 3 and Apollo DN3000, and in a wide variety of embedded systems and industrial control systems. The 68000 was also used in the Macintosh, the first model of the Macintosh was powered by a Motorola 68000 CPU. The processor was eventually succeeded by the 68020 and 68030, which offered improved performance and additional features.

The 68000 has a 32-bit instruction set, with 32-bit registers and a 16-bit internal data bus. The address bus is 24-bit and does not use memory segmentation, making it easier to address memory. There are three ALU's (Arithmetic Logic Unit), two for calculating addresses, and one for data, and the chip has a 16-bit external address bus.

The 68000 architecture was expanded with 32-bit ALUs, and caches. Here is a list with some 680x0 versions and their major improvements:

  • 68010 - Virtual memory support
  • 68020 - 32-bit ALU & Instruction Cache
  • 68030 - On-Chip MMU, 2x 256 byte cache
  • 68040 - 2x 4K Cache, 6 stage pipeline, FPU
  • 68LC040 - No Floating Point Unit (FPU)
  • 68060 - 2x 8K Cache, 10 stage pipelinet

Technical Details
Released 1987 Brand Commodore Type Commodore Amiga Desktops Name Amiga 2000 CPU Class 68000 CPU Motorola 68000 @7.16MHz Memory RAM: 1MB
RAM max: 9MB
Sound Chip Paula - 4 DMA-driven 8-bit PCM channels Sound 4x8-bit channels @28 kHz stereo Display Chip Denise Display 320x200 in 4096 colors
640x200 in 16 colors
1280x200 in 4 colors
Vertical resolution could be doubled using interlacing.
Best Color 12-bit color, 4096 simultanuous Best Graphics 640x400 interlaced (640x512 on PAL) Sprites 8 16pixel wide/scanline 3 colors System OS AmigaOS 2.0 Storage Dual Internal 3.5" Floppy Disk Drives. Original Price $1,500
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Amiga  2000 (1987)
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World Wide Web Links
 
Wikipedia: Motorola 68000 CPU Family
WikiPedia page on the Motorola 68000 series of processors