PC Engine

PC Engine

The PC Engine was a collaborative effort between the relatively young Hudson Soft (founded in 1973) and NEC. NEC's interest in entering the lucrative video game market coincided with Hudson's failed attempt to sell designs for then-advanced graphics chips to Nintendo,^[5] similar to Nintendo's later rejection of Sony's designs for a Super Famicom CD attachment which evolved into the PlayStation.

The PC Engine is a relatively compact video game console, owing to an efficient three-chip architecture and its use of smallROM cartridges called HuCards. Hudson Soft developed the HuCard (Hudson Card) from the Bee Card technology it piloted on the MSX. HuCards, or TurboChips in the US, are about the size of a credit card, but slightly thicker. They are not unlike the slim cartridge reserved for low-budget game releases on the Sega Master System.

The console's CPU is a Hudson Soft HuC6280 8-bit microprocessor. Its 16-bit graphics processor and video color encoder chip were also developed by Hudson Soft.^[6]

The PC Engine initially performed well in Japan, beating Nintendo's Famicom in sales soon after its release, with no fewer than twelve console models released between 1987 and 1993.^{[citation needed]} Despite the system's early success, it started to lose ground to the Super Famicom. NEC made one final effort to resuscitate the system with the release of the Arcade Card expansion, bringing the total amount of RAM up to 2048k, nearly as much as a Sony PlayStation. Some Arcade Card games were conversions of popular Neo Geo titles. The expansion card was never released outside Japan.

New commercial titles were released for the PC Engine up until 1999.^[7]

CD-ROM² / TurboGrafx-CD

CoreGrafx II with Super-CD-Rom² unit

The PC-Engine was the first video game console to have a CD-ROM peripheral, and to use CD-ROM as a storage medium for video games.^[8][9] NEC released the CD-ROM² (シーディーロム2 Shī Dī Romu Romu^?) in Japan on December 4, 1988,^[10] and released the TurboGrafx-CD in the United States on August 1, 1990. NEC was also the first to market a game console with an integrated CD-ROM drive: the PC Engine Duo of 1991.

The TurboGrafx-CD had a launch price of $399.99, and did not include any bundled games.^[11] Fighting Street (Street Fighter) and Monster Lair (Wonder Boy III: Monster Lair) were the TurboGrafx-CD launch titles; Ys Book I & II soon followed. However, the TurboGrafx-CD catalog grew at a very slow rate compared to the library of TurboChip (HuCard) titles.

The TurboGrafx-CD came packaged in a very large box, most of which was filled with protective styrofoam inserts.^{[citation needed]} The TurboGrafx-CD did however come with a large plastic "carrying case" that could comfortably hold the TurboGrafx-16 base system, TurboGrafx-CD, all AC adapters, 2-3 controllers, and a few games.^{[citation needed]}

Although the TurboGrafx-CD library was relatively small, American gamers could draw from a wide range of Japanese software since there was no region protection on any PC Engine or TurboGrafx-16 CD-ROM software. Although Japanese CD-ROM games were compatible with the North American CD-ROM, Japanese HuCards required an adapter, as the pin assignments were different from the Japanese PC-Engine HuCards. Many mail order (and some brick-and-mortar) import stores advertised Japanese CD and HuCard titles in the video game publications of the era.^{[citation needed]}

In addition to small BIOS updates, two "upgrades" to the CD-ROM² would follow: the Super CD-ROM² (スーパーシーディーロム2 Sūpā Shī Dī Romu Romu^?) and its "Super System Card" (スーパーシステムカード Sūpā Shisutemu Kādo^?) (added 192KB of RAM); and the Arcade CD-ROM² (アーケードシーディーロム2 Ākēdo Shī Dī Romu Romu^?) and its "Arcade Cards" (アーケードカード Ākēdo Kādo^?) (Pro and Duo, added a huge 2MB of RAM). Again, these were not compatible with the TurboGrafx-16 without an adapter.

Variations

Several variations and related products of the PC Engine were released throughout the 1990s.

SuperGrafx

Main article: PC Engine SuperGrafx

The SuperGrafx is a variation of the standard PC-Engine hardware. This system is nearly identical to the original PC Engine, except it has a second HuC6270A (VDC), a HuC6202 (VDP) to combine the output of the two VDCs, four times as much RAM, twice as much video RAM, and a second layer/plane of scrolling. The CPU, sound, and color palette were not upgraded, making the expensive price tag a big disadvantage to the system. NEC also decided to not include the extra two video chips in the all-in-one Duo replacement system, essentially killing off any chance of the SuperGrafx continued support. Only five exclusive SuperGrafx games and two hybrid games (Darius Plus and Darius Alpha took advantage of the extra video hardware if played on a SuperGrafx) were released, and the system fell into obscurity.

Minor variations

Other members of the PC Engine family include the Shuttle, the LT (a laptop version similar to the Game Boy Advance SP, but considerably larger), the CoreGrafx I and II, the Duo R and the Duo RX. Contrary to popular belief, the CoreGrafx is not a European version of the PC Engine. It is simply a reengineered version of the original (white) PC Engine with an AV output instead of the original model's RF output. The PC Engine and its derivatives were not officially released in Europe, although many systems and most accessories and games were available as imports. The PC Engine and its games had been extensively covered by most major European video game magazines and were surprisingly popular.

PC Engine Duo

Main article: TurboDuo

In 1991 NEC Home Electronics released the PC Engine Duo. The system combined the PC Engine and the Super CD-ROM² into a single unit. The system could play audio CDs, CD+Gs, CD-ROM2 and Super CD-ROM² games as well as standard HuCards.

It was later released in 1992 by TTI (Turbo Technologies Inc.) in North America as the TurboDuo and was originally bundled with one control pad, an AC adapter, RCA cables, Ys Book I & II (a CD-ROM² title), and a Super CD-ROM² including Bonk's Adventure, Bonk's Revenge, Gate of Thunder and a secret version of Bomberman accessible via an easter egg. The system was also packaged with one random HuCard game which varied from system to system (Dungeon Explorer was the original HuCard pack-in for TurboDuo, although many titles were eventually used, such as Irem's Ninja Spirit and Namco'sFinal Lap Twin, and then eventually a random pick). The Super System Card required for some games when using the original CD add-on as well as some of the Japanese variants of the TurboGrafx was built into the Duo rather than requiring the card to be inserted at all times when playing CD games.

TurboExpress

Main article: TurboExpress

TurboExpress handheld

The TurboExpress was a portable version of the TurboGrafx, released in 1990 for $249.99 (the price was briefly raised to $299.99, soon dropped back to $249.99, and by 1992 it was $199.99). It was the most advanced handheld of its time and could play all the TG-16's HuCard games five years before the Sega Nomad could do the same for Sega Genesisgames. Its Japanese equivalent was the PC Engine GT'. It had a 2.6-inch (66 mm) backlit, active-matrix color LCD screen, the most advanced on the market for a portable video game unit at the time. The screen contributed to its high price and short battery life, however. Its keypad layout is similar to that of the original Game Boy (the TG-16 controller's keypad layout was similar to that of the Famicom/NES controller also). It shared the capabilities of the TurboGrafx, giving it 512 available colors (9-bit RGB), stereo sound, and the same custom CPU at 7.15909 MHz. The optional "TurboVision" TV tuner included RCA audio/video input, allowing the user to use TurboExpress as a video monitor. The "TurboLink" allowed two-player play. Falcon, a flight simulator, included a "head-to-head" dogfight mode that could only be accessed via TurboLink. However, very few TG-16 games offered co-op play modes especially designed with the TurboExpress in mind.

Stand-alone systems

• PC Engine (1987)
  • White, only RF output
• PC Engine Shuttle (1989)
  • UFO-shaped system, unique expansion port (no CD option), AV output
• PC Engine SuperGrafx (1989)
  • The only PC Engine unit to contain enhanced HuCard functionality. Only five games were released for it (two regular PC Engine releases, Darius Plus and Darius Alpha, were enhanced to utilize the extra sprite capability of the SuperGrafx).
• PC Engine CoreGrafx (1989)
  • Dark grey, blue label, AV output
• PC Engine CoreGrafx II (1991)
  • Light grey, orange label, AV output, Identical in function to the CoreGrafx

CD-ROM accessories

Core-Grafx with CD-ROM² and interface unit

• CD-ROM² (1988)
  • White "briefcase" design matching the style of the original PC Engine. A special adaptor, named RAU-30, is required to connect it to the SuperGrafx.
• Super CD-ROM² (1991)
  • A grey-colored CD attachment system add-on, with built-in SystemCard 3.0 to play all Super CD-ROM² games in addition to CD-ROM² game formats. It can be connected directly to the rear pinouts of the original white PC Engine, the PC Engine CoreGrafx, CoreGrafx2, and lastly the SuperGrafx. A special adaptor, named PI-AD18, is required to connect it to the PC-Engine-LT. However, the Super CD-ROM² tend to be much more difficult to find.

Portable systems

PC-Engine LT

• PC Engine GT (1990)
  • Portable system, identical in shape and function to the U.S.-releasedTurboExpress
• PC Engine LT (1991)
  • Semi-portable system (no battery option) similar in size to a normal PC Engine or CoreGrafx. Uses a very large attached screen, and folds up like a laptop (hence the LT moniker)

Duo systems

PC Engine Duo RX

• PC Engine Duo (1991)
  • Combination PC Engine + CD ROM system + System 3.0 card, dark grey, has a CD door lock and headphone port
• PC Engine Duo R (1993)
  • Same as the Duo, but white/beige with a more streamlined case style, and lacks the lock and headphone port.
• PC Engine Duo RX (1994)
  • Same as the Duo R, slightly blue in color. The only PCE packaged with a six-button pad.

Others

• X1 Twin
  • Combination of X1 computer and PC Engine. Only played HuCards.
• Pioneer LaserActive
  • Pioneer and NEC released a LaserDisc player with video game modules. One module allowed the use of PC Engine games (HuCard, CD-ROM² and Super CD-ROM²) as well as new "LD-ROM²" titles that only worked on this device.
• PC-KD863G
  • A computer (RGB) monitor with a built-in PCE. Only played HuCards.

Other region variations

• TurboGrafx-CD - American version of CD-ROM²
• TurboExpress - American version of PC Engine GT
• TurboDuo - American version of PC Engine Duo
• TurboGrafx - United Kingdom, PAL video output

Unofficial variations

• Various PC Engine Shuttle clones exist, with varying levels of compatibility with original PC-Engine games. One of the more common types is the "PC Boy".
• New Tai Sang Corporation released bootleg HuCards which were sometimes patched to add features like invincibility. Unlike most bootlegs these closely resembled the original games in terms of packaging, even with color labels and manuals.
• The PC Engine was never officially released in continental Europe, but some companies imported them and made SCART conversions on a moderate scale. In France, a company known as Sodipeng imported Japanese systems and added an RGB Cable called "AudioVideo Plus Cable". This mod improved the original video signal quality extensively and made the consoles work with SECAM televisions. In Germany, several importers sold converted PC Engines with PAL RF as well as RGB output. The connectors and pinouts used for the latter were frequently compatible with theAmiga video port, with two unconnected pins used for the audio channels.

Unreleased hardware

• A modem was developed but never released (some working prototypes are in circulation, though).
• A SCSI interface for the Duo CD-ROM drive to be used by a PC existed in prototype form only (it was featured in a TTi-published TurboGrafx-16 oriented magazine in the US and on Computer Chronicles episode #1043).

Peripheral compatibility

The TurboGrafx-16 had only one controller port, so any multiplayer games required the TurboTap accessory.

All PC Engine systems support the same controller peripherals, including pads, joysticks and multitaps. Except for the Vistar, Shuttle, GT, and systems with built-in CD-ROM drives, all PC Engine units shared the same expansion connector, which allowed for the use of devices such as the CD-ROM unit, game saves and AV output.

The TurboGrafx and Vistar units use a different controller port than the PC Engines, but adaptors are available and the protocol is the same. The TurboGrafx offers the same expansion connector pinout as the PC Engine, but has a slightly different shape so peripherals must be modified to fit.

The Super System Card provides 192 kB of RAM, supplementing the built in 64K of DRAM found in the CD interface tray. The PC-Engine Duo/R/RX consoles have the Super System Card’s 192 kB of RAM plus the 64K of standard RAM and v3.00 BIOS software built in, and can play both CD-ROM² and Super CD-ROM² games without using any additional cards.

The Arcade Card Pro is designed for the original CD-ROM² and Super CD-ROM² peripherals, adding the 2304 kB of RAM required by Arcade CD-ROM² games. It could, of course, also play standard CD-ROM² and Super CD-ROM² games.

The Arcade Card Duo is for the PC-Engine Duo/R/RX consoles and adds 2048 kB RAM. Because the PC-Engine Duo series of systems have 256K of RAM built-in, this does not need to be provided and is why the Arcade Card Duo contained less RAM and was less expensive than the Pro version.

Note: Since the aforementioned consoles use the same BIOS revision as the Arcade Card Pro, it is not known (as a cost-saving measure) if the Arcade Card Duo includes the BIOS software itself, or if the existing built-in BIOS is used.

The various CD-ROM game types are:

• CD-ROM² : Standard CD-ROM game.
• Super CD-ROM² : Requires a compatible system or upgrade card.
• Arcade CD-ROM² : Requires an upgrade card.

While the standard CD-ROM² and Super CD-ROM² had RAM for data storage which was accessed directly, the Arcade CD-ROM² cards accessed the RAM in a slightly different way.

Both the Pro and Duo versions of the Arcade Card worked in the same way. Just as with the Super CD-ROM², up to 256 kB of the RAM was able to be accessed directly by the CPU. The other 2048 kB was accessed indirectly by four indirect self incrementing/decrementing address registers. These registers were mapped into memory hardware bank and also mapped into 4 special memory banks. Reading and writing sequential data was speed up and reduced cycle cost due to these new registers. This meant *far* data could be accessed with these four registers without having to map banks of memory into the CPU's logical address range, and could be transferred to VRAM ports faster and easier, as is evidenced by the many conversions of well-animated Neo Geo fighting games to the Arcade CD-ROM². The Arcade card was known to have existed in working prototype form as early as mid '92 from looking at (non public) source code files to Art of Fighting ACD port.

One technique that was used by games pre-dating the Arcade Card upgrade was to store graphics data in the 64K audio RAM (used for ADPCM samples) that was present. This RAM could be directly populated by the CD-ROM hardware (it had a direct DMA channel from the CD controller) without CPU intervention, and the memory could be accessed in an indirect fashion, similar to the Arcade Card but at a much-much slower interface, allowing data stored in it to appear as a 64 kB stream of linear data that could be easily transferred to the system RAM.

NEC also manufactured a very large line of personal computers, one of which featured a single-speed CD ROM drive identical to the PC Engine version. They were designed to be interchangeable, which is why the PC Engine's IFU-30 CD ROM interface could be purchased without a CD ROM drive.

NEC developed a prototype adaptor that connected a PC through the HuCard slot, allowing the PC to control the PC Engine's CD ROM as it would any normal SCSI drive. Due to falling CD drive prices and the increasing undesirability of a single-speed SCSI drive, it was never released. It was however previewed in NEC's official U.S TurboDuo magazine.

The Pioneer LaserActive was a laserdisc player with an expansion bay. One of the expansion modules released allowed it to play PC Engine titles (HuCards, CD-ROM² and Super CD) as well as games released on laserdisc (LD-ROM²) that only worked on this setup. Eleven LD-ROM² titles were released in Japan, though only three of them were released in North America.

Video formats

All PC Engine hardware outputs video in NTSC format, including the European TurboGrafx; it generates a PAL-compatible video signal by using a chroma encoder chip not found in any other system in the series.

Technical specifications

The American TurboGrafx-16 console with CD unit

• CPU: 8-bit HuC6280A, a modified 65SC02 (a separate branch from the 65C02, of the original MOS 6502) running at 1.7897725 MHz or 7.15909 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). TheHuC6270A featured Port-based I/O similar to the TMS99xx VDP family.

Display

Resolution

• X (Horizontal) Resolution: variable, maximum of 565 (programmable to 282, 377 or 565 pixels, or as 5.3693175 MHz, 7.15909 MHz, and 10.738635 MHz pixel dot clock)^[12] Taking into consideration overscan limitations of CRT televisions at the time, the horizontal resolutions were realistically limited to something a bit less than what the system was actually capable of. Consequently, most game developers limited their games to either 256, 352, or 512 pixels in display width for each of the three modes.^[13]
• Y (Vertical) Resolution: variable, maximum of 242 (programmable in increments of 1 scanline). It is possible to achieve an interlaced "mode" with a maximum vertical resolution of 484 scanlines by alternating between the two different vertical resolution modes used by the system. However, it is unknown, at this time, if this interlaced resolution is compliant with (and hence displayed correctly on) NTSC televisions.
• The majority of TurboGrafx-16 games use 256×239,^[12] though some games, such as Sherlock Holmes Consulting Detective did use 512×224.

Color

• Colors available: 512 (9-bit)
• Colors onscreen: Maximum of 482 (241 background, 241 sprite)
• Palettes: Maximum of 32 (16 for background tiles, 16 for sprites)
• Colors per palette: 16 per background palette (color entry #0 of each background palette must be the same), and 15 per sprite palette (plus transparent, which is displayed as an actual color in the overscan area of the screen)

Sprites

• Simultaneously displayable: 64 on-screen, 16 (256 sprite pixels) per scanline
• Sizes: 16×16, 16×32, 16×64, 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 by manipulating a bit which caused indirect pixel color entry #0 of the background tile(s) to act as transparent.

Tiles

• Size: 8×8
• Palette: Each background tile can use up to 15 unique colors via one of the 16 available background palettes and 1 shared color (BG color #0) for a total of 16 colors per tile. The first color entry of each background subpalette is ignored. Instead, color #0's RGB value is shown in its place (the common/shared color). When a specific sprite is set to show behind the BG layer via the priority bit, all tiles that use relative color #0 (of 16) will not show BG color #0. But instead will show the sprite pixel (if not opaque).
• Layers: The HuC6270A VDC was capable of displaying one background layer.

Memory[edit]

• Work RAM: 8 kB
• Video RAM: 64 kB

Audio Capacity

• Six Wavetable Synthesis audio channels, programmable through the HuC6280A CPU.
• Each channel had a frequency of 111.87 kHz for single cycle of 32 samples (while not in D/A mode) with a bit depth of 5 bits. Each channel also was allotted 20 bytes (32×5 bits) of RAM for sample data.
• The waveforms were programmable so the composers were not limited to the standard selection of waveforms (square, sine, sawtooth, triangle, etc.). But the use of standard waveforms, and semi-standard forms, such as a 25% pulse wave were used fairly often.
• The first two audio channels (1 and 2) were capable of LFO when channel #2 was used to modulate channel #1. In theory, this could also be used to perform an FM operation, though due to other limitations, this was never done (note: LFO, like FM works by modifying an audible waveform (carrier oscillator) with an inaudible waveform (modulator oscillator), but LFO's modulator is subsonic rather than sonic (FM), so LFO will not change the carrier's timbre, just its behavior, and as a result, LFO does not really sound anything like FM.)
• The final two audio channels (5 and 6) were capable of Noise generation.
• Optional software enabled Direct D/A which allows for sampled sound to be streamed into any of the six PSG audio channels. When a channel is in D/A mode the frequency is as fast as the CPU can stream bytes to the port, though in practicality it is limited to 6.99 kHz when using the TIMER interrupt with its smallest loop setting (1023 cpu cycles) or 15.7 kHz using the scanline interrupt.
• There is a method that combines two channels in DDA mode to play back 8-bit, 9-bit, or 10-bit samples.
• The addition of the CD-ROM peripheral adds CD-DA sound, and a single ADPCM channel to the existing sound capabilities of the PC Engine.
• Sound system is often mistakenly called PSG, but this is incorrect. It is Wavetable Synthesis. The fairly common use of standard and semi-standard waveforms is the most likely source of the confusion. But PSG and Wavetable do not generate sound the same way. So, even when they're both making exactly the same tone, there's still something completely different going on "under the hood." The only point at which the term PSG may ever be appropriately used when applied to this sound system is in the ability to use white noise on channels 5 and 6.

Game media

• HuCard (Turbo Chip in North America): A thin, card-like game medium. The largest Japanese HuCard games were up to20 Mbit in size. The name was derived from Hudson Soft, the company who developed the game card technology.
• CD: The PC Engine CD was the first home video game console to offer a CD-ROM accessory.
• With only one exception, the PC Engine SuperGrafx, all PC Engine hardware could play the entire HuCard library, and every CD system could play all of the licensed CD games - with the right system card. Some unlicensed CD games by Games Express required a Duo system, due to their games requiring both a special system card packaged with the games and the 256 kB of RAM built into the Duo.

CD hardware technical specifications and information

• Oki MSM5205 ADPCM chip with variable speed input clock, and 64 kB DRAM for audio sample storage. Only one channel of 4-bit compressed audio (decompresses to 12-bit, top 10 bits output through DAC) was supported.
• Programmable, timer controlled, electronic volume attenuator to fade-out the CD-DA and ADPCM audio channels together or individually.
• The PC-Engine CD-ROM interface tray has 64 kB of DRAM for storage of program code and data loaded from the CD.
• The "System Card" contains the BIOS program used to boot CD media and provides functions for software to access CD hardware through a standardized interface. Later System Cards had extra RAM and updates to the BIOS.
• The Duo series has the same BIOS ROM (v3.00) and RAM (256 kB total) as a PC-Engine system equipped with a Super System Card. The Duo implements the memory as a single 256 kB SRAM chip rather than the split 64 kB DRAM / 192 kB SRAM.
• The list of known CD-ROM BIOS revisions are:
  • v1.00 - First release (HuCard, came with the PC-Engine CD-ROM interface unit)
  • v2.00 - Upgrade (HuCard, sold separately)
  • v2.10 - Upgrade (HuCard, sold separately)
  • v3.00 - Final release (built into several products and available as a HuCard - see below)
• The list of known System Card releases are:
  • System Card, v1.00 - First release. Came packaged with the original PC-Engine CD-ROM² System. Also available as a standalone purchase, in case the pack-in System Card was lost or damaged.
  • System Card, v2.00 – BIOS update. The only difference between this and the original System Card is the BIOS code update to v2.00. Otherwise, it is the same.
  • System, Card, v.2.10 – BIOS update. This may have been a bug fix for the System Card v2.00 BIOS code.
  • Super System Card - 1.5 Mbit RAM (192 kB) – RAM upgrade and BIOS update. This expands the RAM available for the CD-ROM unit to 256 kB when including the existing built in DRAM. It also offers a final BIOS update to v3.00. The PC-Engine Duo (Turbo Duo in North America) had 256 kB of RAM and the same v3.00 BIOS built into the system. Games developed for this System Card bore the title "Super CD-ROM²", and could not be played using an older System Card.
  • Arcade Card Pro - 17.5 Mbit RAM (2240 kB as 2 MB+192 kB) – RAM upgrade. This greatly expands the RAM available for the CD-ROM unit to 2240 kB. The BIOS revision was unchanged from v3.00. Games developed for this System Card bore the title ‘Arcade Card CD’, and could not be played using an older System Card. The Arcade Card Pro includes the extra 192 kB needed by the non Duo CD system. The 2 MB of RAM is accessed through ports or units of single 8 kB banks and is intended for graphics data storage rather than program code; its flexible addressing system allows for rapid transfer of data to VRAM.
  • Arcade Card Duo – 16 Mbit RAM (2048 kB) – RAM upgrade. This greatly expands the RAM available for the PC-Engine Duo system to 2048 kB. The BIOS revision was unchanged from v3.00. Games developed for this System Card bore the title ‘Arcade Card CD’, and could not be played using an older System Card. This will only work on the Duo systems, as it does not include the extra memory built into the Duo system.
  • Games Express Card – Bootleg system card. This was a bootleg System Card released by Games Express for play of unlicensed Games Express CD games. Only unlicensed Games Express games could be played on this System Card.