Commodore Amiga 500

The Commodore Amiga 500, known as the Amiga 500, is a personal computer in the Commodore Amiga range that was released in 1987 at the same time as the Commodore Amiga 2000. While the latter was aimed at a professional and advanced user market, the Amiga 500 was aimed at the home and video game market. Both were announced at the Consumer Electronics Show in January 1987. The starting price, without monitor, in the United States was $595.95.

It has been the best-selling model in the range, with remarkable success in Europe, where it dominated the computer video game market, rivaling the Sega Megadrive and Super Nintendo video game consoles.

Due to different electrical and television standards, two main versions of the motherboard are built, one for NTSC (United States, Japan, and others) and one for PAL (Europe and part of Asia). SECAM standard areas (France, Eastern Europe) use PAL equipment. The differences are mainly in clock frequencies. However, the graphics chips are able to switch between both modes without problems if you have an RGB monitor.

In addition to the standard package, several variants of the included software have been distributed. In October 1989, the Batman Pack was released, which was distributed in the United Kingdom.

In Christmas 1991, it is partially replaced by the Commodore Amiga A-500 Plus (an improved version of the Amiga 500). Both cease to be manufactured in mid-1992, being replaced by the Commodore Amiga 600 and later by the Commodore Amiga 1200. Despite being more advanced machines, neither achieves the success of the Amiga 500.

Commodore Amiga 500.

Technical specifications

• CPU CISC Motorola 68000 to 7.16 MHz version NTSC, or 7.1 MHz the PAL. Although it implements a 32-bit model and has 32-bit records, as well as an internal 32-bit data bus, its three ALUs are 16-bit, its external data bus is 16-bit and its address bus is 24-bit, so it can only address 16 MB of RAM.
• ROM: of 512 KB containing the Kickstart.
• RAM: 512 KB of CHIP RAM by default (sound buffers, graphic memory and software coexist in the same space), expandable to 1 MB of CHIP RAM and up to 8 MB of Fast RAM (directed only by the microprocessor, without sharing it with the rest of the chipset). The Fast RAM could then be extended to 128 MB with an accelerating card.
• Operating system: AmigaOS 1.2 or 1.3 (with a preferred 32-bit multitasking micronucleus) depending on the review.
• Chipset OCS/ECS in A500+ disguised from Amiga 500.
• Versions to 50 Hz PAL or 60 Hz NTSC depending on the country.
• Software controlable audio bass filter (LED for bright operation with the activated filter, darker with the off filter).
• Interruption sharing IRQ (like the PCI bus).
• IRQ system with 7 levels of interruption priorities.
  • No limit on the number of interruptions used.
  • Resources managed by Autoconfig, very similar to ACPI. Resources were not numbered or labeled, simply given as quantities and memory addresses.
• There are no specific E/S ports, use E/S mapped in memory separately for each device.
• Support:
  • 3.5" and double density internal disk drive, 880 KB in standard Amiga format, read/write disks in MS-DOS format using an additional file system. Due to its controller, it is able to read/write almost any dual density format.
  • Up to 3 connectable external disk drives in chain, 3.5" or 5.25".
  • External hard drive IDE or SCSI through expansion (can incorporate more benefits, such as memory expansions).
  • Optional Amiga A570 CD-ROM external unit.
• Keyboard: standard Amiga QWERTY/QWERTZ/AZERTY mechanical with Mitsumi switches, consisting of 96 keys including 10 function keys, Help, Delete, four cursor block and numerical keyboard.
• Housing: rectangular with the part of the inclined plane keyboard, very similar to that of Commodore 64c. On the left side, protected by a springboard, is the Zorro II connector. In law, integrated disk drive. In the back, connectors.

Connectors

• Two connectors for digital joysticks and mouse (DE-9). The mouse must support the proprietary protocol or connect with an adapter.
• Two stereo sound connectors (RCA).
• An external disk drive port (DB-23F), to connect up to 3 chain drives.
• A RS-232 serial port (DB-25).
• Centronics parallel printer port (DB-25).
• External power connector (+5V, +/-12V).
• Analog RGB connector with video output to 50 Hz PAL or 60 Hz NTSC (DB-23M). It can be used with video monitors such as Commodore 1084S or, by adapters, with multisynchronous VGA monitors or any equipment with a full euroconector. The use of a common VGA monitor requires an additional peripheral to bend the sweep speed, given the difference between the original Amiga signal (~15 kHz) and the one that supports these monitors (~31 kHz+).
• Monochrome video connector (RCA).
• Zorro II bus expansion connector on the left side.
• Internal expansion connector, accessible through a lower tray, for RAM expansions, real time watch and others.