TRS-80 & Compatibles  Color Genie EG2000
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Introduction

The Color Genie was produced by EACA, a Hong Kong based manufacturer, and introduced in Germany in 1982. The computer followed the Genie II and was released around the same time as the more business focused Genie III. The BASIC was compatible with TRS-80 but had extended commands for graphics and sound, as these were enhanced.

The Color Genie is based on the TRS-80 architecture, but is not compatible with the TRS-80 Color Computer (CoCo) as it uses the Z80 CPU where the CoCo range used the Motorola MC6809E CPU.

The computer has the following ports:

  • Composite Video Out
  • Integrated RF Modulator with TV OUT
  • Cartridge expansion slot
  • 1200 baud 5-pin DIN Tape Interface
  • RS-232 port
  • Lightpen Port
  • Parallel port for printer, or joystick controller

Motorola 6845 CRTC Display Controller

The Motorola 6845 or MC6845, is a Display controller used in many 8-bit computers in the early 1980s. It was originally designed to be used with the Motorola 6800 CPU, but was also used alongside various other processors such as the Z80, and the MOS 602.

The 6845s main function is to properly time access to the display memory, and to calculate the memory address of the next portion to be drawn. Other circuitry in the machine then uses the address provided by the 6845 to fetch the pattern and then draw it. The implementation of that hardware is entirely up to the designer and varied widely among machines. The 6845 is intended for character displays, but could also be used for pixel-based graphics, with some clever programming.

Computers that used the 6845 are, among others:

  • BBC Micro
  • Amstrad CPC
  • Videx VideoTerm display cards for Apple II
The Chip is also used in some of the early PC video cards such as the MDA, the Hercules Graphics Adapter, the Color Graphics Adapter (CGA) and the Plantronics Plus graphcis card. The functionality was later duplicated on EGA and VGA hardware for backward compatibility.

Source: WikiPedia

Programmable Sound Generator (AY-3-8910 compatible PSG)

The AY-3-8910 is a 3-voice Programmable Sound Generator, or PSG. It was designed by General Instrumet in 1978 for use with their own 8-bit PIC1650 and their 16-bit CP1610 computers.

The PSG is widely used in many arcade cabinets, pinball machines, and many micro-computers. Here is a list of some of the major brands of computer that used the AY-3-8910:

  • Intellivision
  • Vectrex
  • Amstrad CPC range
  • Oric-1
  • Color Genie
  • Elektor TV Games Computer
  • All MSX-1 and MSX-2 computers
  • ZX Spectrum home computers

General Instrument spun of MicroChip Technology in 1987 and the chip was sold under the MicroChip brand, and licensed to Yamaha as the YM2149F which the Atari ST range of computers use. Functionally the PSG is very similar to the Texas Instruments SN76489.

Variants:

  • AY-3-8910
    Comes with 2 general purpose 8-bit parallel I/O ports, used for Keyboard and Joystick in for instance MSX.
  • AY-3-8912
    Same chip, but in a 28-pin package. Parallel port B is not connected to save cost and space.
  • AY-3-8913
    Same chip, but in a 24-pin package. Both parallel ports are not connected.
  • AY-3-8914
    The AY-3-8914 has the same pinout and is in the same 40-pin package as the AY-3-8910, except the control registers on the chip are shuffled around, and the 'expected input' on the A9 pin may be different. It was used in Mattel's Intellivision console and Aquarius computer.
  • AY-3-8930
    Backwards compatible but BC2 pin is ignored
  • YM2149F
    Yamaha Produced chip, same pin-out as the AY-3-8910, but pin 26 could halve the master clock. Can be used to replace the AY-3-8910 if pin 26 is left disconnected.
  • YM3439-D
    CMOS version of the Y2149 in 40-pin DIP
  • YM3439-F
    CMOS version of the Y2149 in 44-pin QFP
  • YMZ294
    Variant of the YM3249 in an 18-pin package. Parallel ports not connected, and all sound channels mixed on 1 port.
  • T7766A
    Toshiba variant of the AY-3-8910, fully compatible. Used in some MSX models.
  • Winbond WF19054, JFC95101, and File KC89C72: Fully compatible versions of the AY-3-8910 produced for slot machines.

Zilog Z80 CPU Family

The Z80 quickly became popular in the personal computer market, with many early personal computers, such as the TRS-80 and Sinclair ZX80, using the Z80 as their central processing unit (CPU). It was also widely used in home computers, such as the MSX range, SORD, and the Amstrad CPC, as well as in many arcade games. Additionally, it was also used in other applications such as industrial control systems, and embedded systems. The Z80 was widely used until the mid-1980s, when it was gradually replaced by newer microprocessors such as the Intel 80286 and the Motorola 68000.

The Z80 microprocessor was developed by Zilog, a company founded by Federico Faggin in 1974. The Z80 was released in July 1976, as a successor to the Intel 8080. It was designed to be fully compatible with the 8080, but also included new features such as an improved instruction set, more powerful interrupts, and a more sophisticated memory management system.

The Z80 quickly became popular in the personal computer market, with many early personal computers, such as the TRS-80 and Sinclair ZX80, using the Z80 as their central processing unit (CPU). It was also widely used in home computers, such as the MSX range, SORD, and the Amstrad CPC, as well as in many arcade games. Additionally, it was also used in other applications such as industrial control systems, and embedded systems. The Z80 was widely used until the mid-1980s, when it was gradually replaced by newer microprocessors such as the Intel 80286 and the Motorola 68000. The design was licensed to Synertek and Mostek as well as the European SGS.

The Z80s instruction set is binary compatible with the Intel 8080, so that 8080 code such as the CP/M Operating System and Intel's PL/M compiler for the 8080 can run unmodified on the Z80. The Z80 had many enhancements over the 8080 such as 16-bit data movement instructions, block copy and block I/O instructions, single bit addressing of all registers, IX/IY offset registers, better interrupt system and a complete duplicate register file for context switching during an interrupt.

Source: WikiPedia
Technical Details
Released 1985 Brand EACA Type TRS-80 & Compatibles EACA Name Color Genie EG2000 CPU Class Z80 CPU NECD780 (Z80 clone) @2.2MHz Memory RAM: 16kB
RAM max: 32kB
Sound Chip none Sound 3 wave channels + white noise Display Chip Motorola 6845 CRTC Display 40x25 Text, 16 colors, 128 User Defined characters. 160x96 Graphics 4 color. Best Color 4 colors Best Graphics 160x96 in 4 colors Sprites none System OS TRS-DOS Storage External Tape, or Floppy disk controller, 12KByte EPROM cartridge
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World Wide Web Links
 
WikiPedia: Motorola 6845 CRTC Display Controller
Wikipage about the Motorola 6845 CRTC Display Controller Chip.
 
WikiPedia: General Instrument AY-3-8910
Wikipage about the AY-3-8910 and compatible Programmable Sound Generators
 
Wikipedia: The Z80 CPU
Wikipedia page on the very popular Z80 8-bit CPU used in many computers of the 1980's era.