The TurboDuo (also called Turbo Duo) is a video game console released in the United States on October 10, 1992 by Turbo Technologies Incorporated, a Los Angeles-based corporation consisting of NEC and Hudson Soft
employees, established to market NEC consoles in North America after
NEC Home Electronics USA failed to effectively market the platform. The
Duo was codeveloped by Hudson Soft and NEC. The Japanese counterpart was the PC Engine Duo game console, which was released over a year earlier.
The TurboDuo is essentially a combination of TurboGrafx-16 and TurboGrafx-CD
hardware, plus the Super System BIOS + extra 192k RAM built-in to the
motherboard. The TurboDuo was capable of playing standard audio CDs,
CD+Gs, TurboGrafx TurboChips, Japanese and North American CD-ROM²
(TurboGrafx-CD) and Super CD-ROM² titles. The system is able to play
Japanese PC Engine HuCARDs with a third party HuCARD converter or
modification. With a HuCARD converter plus a Japanese Arcade Card Duo,
the system can also play Japanese Arcade CD-ROM games.
TurboChip is simply the North American term for HuCARD.
CPU: 8-bit HuC6280A, a modified 65C02
running at 3.58 or 7.16 MHz (switchable by software). Features
integrated bankswitching hardware (driving a 21-bit external address
bus from a 6502-compatible 16-bit address bus), an integrated
general-purpose I/O port, a timer, block transfer instructions, and
dedicated move instructions for communicating with the HuC6270A VDC.
GPU: A dual graphics processor setup. One 16-bit HuC6260 Video Color Encoder (VCE), and one 16-bit HuC6270A Video Display Controller (VDC). The HuC6270A featured Port-based I/O similar to the TMS99xx VDP family.
Resolution:
X (Horizontal) Resolution: variable, maximum of 512 (programmable in increments of 8 pixels)
Y (Vertical) Resolution: variable, maximum of 240 (programmable in increments of 8 pixels)
The vast majority of TurboGrafx-16 games use 256×224, though some
games, such as Sherlock Holmes Consulting Detective did use 512×224.
Chris Covell's 'High-Resolution Slideshow' uses 512×240.
Color:
Depth: 9 bit
Colors available: 512
Colors onscreen: Maximum of 481 (241 background, 240 sprite)
Palettes: Maximum of 32 (16 for background tiles, 16 for sprites)
Colors per palette: Maximum of 16
Sprites:
Simultaneously displayable: 64
Sizes: 16×16, 16×32, 32×16, 32×32, 32×64
Palette: Each sprite can use up to 15 unique colors (one color must
be reserved as transparent) via one of the 16 available sprite palettes.
Layers: The HuC6270A VDC was capable of displaying one sprite layer. Sprites could be placed either in front of or behind background tiles.
Tiles:
Size: 8×8
Palette: Each 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.
Layers: The HuC6270A VDC was capable of displaying one background layer.
Memory:
Work RAM: 8KB
Video RAM: 64KB
Audio capacity:
6 PSG audio channels, programmable through the HuC6280A CPU.
CD titles add Redbook CD-DA sound, and a single ADPCM channel to the existing sound capabilities of the TurboDuo.
Game Media:
TurboChip (HuCARD in Japan): A thin, card-like game media. The largest Japanese HuCard games were up to 20Mbit in size.
Excluding the TurboExpress
(TurboChip only), all TurboGrafx-16 hardware could play the entire
TurboChip library, and every CD system could play all the various CD
format games - with the right system card and/or HuCARD adaptor.
Interestingly, Japanese systems cannot play US TurboChips without a
required internal modification. Some modifications allow Japanese
systems to play US and Japanese cards right from the HuCARD port, other
modifications require a HuCARD converter as well.
