The TurboDuo (later rebranded as simply the Duo) is a fourth-generation video game console developed by NEC Home Electronics and Hudson Soft for the North American market. It combines the capabilities of the TurboGrafx-16 and its CD-ROM drive add-on, the TurboGrafx-CD, into a single, redesigned unit. Initially test-marketed in Los Angeles in October 1992 before a nationwide rollout in May 1993, TurboDuo is the localized version of the Japanese PC Engine Duo, which was released in September 1991.

Compared to TurboGrafx-16 and the TurboGrafx-CD, TurboDuo has an updated BIOS and 192 KB of additional RAM. The RAM increase and BIOS update afford the TurboDuo and PC Engine Duo compatibility with all CD-ROM² and Super CD-ROM² based software (Japanese and North American). Like the TurboGrafx-CD, the TurboDuo can read Audio CDs and CD+G discs. TurboDuo, however, cannot read PC Engine HuCards without modification or an adapter. With a HuCard adapter and an Arcade Card Duo, the TurboDuo can also read Arcade CD-ROM² games (which were sold only in Japan).

Marketing

Japan

thumb|left|The Japanese PC Engine Duo R

When the PC Engine Duo launched in Japan on September 21, 1991, it retailed for ¥59,800. The product garnered a Good Design Award.

NEC later revised the design of the console to reduce both manufacturing costs and the sale price. This new version, the , went to market on March 25, 1993 Turbo, a superhero character, was the alter ego of Jonathan Brandstetter, who himself was based in part on real-life game developer and TurboDuo brand manager John C. Brandstetter. Consisting of a three comic campaign that ran in issues of Electronic Gaming Monthly, the stories featured Johnny opposing agents of the company "FEKA" (a thinly veiled parody of Sega) who were tricking children into buying their CD-based add-on instead of the TurboDuo. Reactions to the advertising campaign were negative, with Jonathan J. Burtenshaw of GameSpy decrying them as "petty" and "overly confrontational," and further conjectured that it hurt TurboDuo sales. Despite this Turbo would later resurface as a playable character voiced by Brandstetter in the 2019 puzzle game Crystal Crisis, and in name and image only for Johnny Turbo's Arcade, a Data East arcade game compilation for the Nintendo Switch produced by Brandstetter's company Flying Tiger Development.

Technical specification

thumb|The Japanese PC Engine Duo

; CPU

: The Hudson Soft HuC6280 is a modified 65C02 with an effective clock rate of 1.79 or 7.16 MHz (switchable by software). The integrated components of this 8-bit processor include a timer, general-purpose I/O port, and bankswitching hardware (which drives a 21-bit external address bus from a 6502-compatible 16-bit address bus). It is capable of block transfer instructions, as well as dedicated move instructions for communicating with the TurboDuo's video display controller, the HuC6270A.

; Video processing

:* One 16-bit HuC6260 video color encoder (VCE)

:* One 16-bit HuC6270A video display controller (VDC). Like the TMS99xx family of video display processors, it has port-based I/O.

; Display resolution

:* Horizontal lines: Maximum of 512, programmable in 8-pixel increments

:* Vertical lines: Maximum of 240, programmable in 8-pixel increments

thumb|right|Since the TurboGrafx-16 used a different controller port, its input devices and peripherals required an adapter in order to be used on a TurboDuo.

; Color

:* Color depth: 9-bit

:* 512-color palette (maximum of 481 colors on-screen: 241 for background tiles, 240 for sprites)

:* Up to 32 palettes (16 for background tiles, 16 for sprites)

:* Up to 16 colors per palette (15 colors + transparency)

; Sprites

:* Sizes: 16×16, 16×32, 32×16, 32×32, 32×64

:* Simultaneously displayable: 64 (maximum of 8–16 per line, depending on sprite width)

:* Each sprite can use up to 15 unique colors (one color must be reserved as transparent) via one of the 16 available sprite palettes.

:* The HuC6270A VDC can display one sprite layer. Sprites could be placed either in front of or behind background tiles.

; Tiles

: Each 8×8-pixel background tile can use up to 16 unique colors via one of the 16 available background palettes. The first color entry of each background palette must be the same across all background palettes. The HuC6270A VDC can display one background layer.

;Memory

:* Work RAM: 8 KB

:* Video RAM: 64 KB

:* Additional 192 KB of built in Memory (System 3.0)

; Sound

:* Six wavetable synthesis audio channels, programmable through the HuC6280 CPU

:* One ADPCM channel

:* Compact Disc Digital Audio

; Software media

:* TurboChip (called HuCard in Japan), a thin, card-like ROM cartridge. Published games consumed up to 20 Mb (2.5 MB).

:* CD-ROM² (pronounced "CD-ROM-ROM" in Japan), a proprietary CD-ROM-based media. Unlike the TurboGrafx-CD add-on, the TurboDuo could play standard CD-ROM² discs, as well Super CD-ROM² discs, without the need of a System Card. Early CD-ROM² games released in North America were branded as TurboGrafx-CD discs, but this relabeling fell into disuse after the launch of the TurboDuo in favor of keeping the CD-ROM² and Super CD-ROM² labeling used in Japan.

See also

  • List of TurboGrafx-16 games/PC Engine games

References

  • PC-Engine technical documentation for programmers at MagicEngine.com
  • Frozen Utopia, a website for PC-Engine game developers