PC Engine SuperGrafx

PC Engine SuperGrafx
PC Engine SuperGrafx system
Manufacturer NEC Home Electronics
Type Video game console
Generation Fourth generation
Release date
Media HuCard, CD-ROM²
CPU Hudson Soft HuC6280
Best-selling game Daimakaimura
Predecessor PC Engine (main system)
Successor PC Engine Duo (updated system)

The PC Engine SuperGrafx (PCエンジンスーパーグラフィックス, Pī Shī Enjin SūpāGurafikkusu), also shortened as the SuperGrafx or PC Engine SG, is a video game console by NEC Home Electronics, released exclusively in Japan. It is an upgraded version of the PC Engine, released two years prior.

Originally announced as the PC Engine 2 (PCエンジン2, Pī Shī Enjin Tsū),[2] the machine was purported to be a true 16-bit system with improved graphics and audio capabilities over the original PC Engine. Expected to be released in 1990, the SuperGrafx was rushed to market, debuting several months earlier in late 1989 with only modest improvements over the original PC Engine.

Only six retail games were produced which took advantage of the improved SuperGrafx hardware,[3] and one of them could be played on a regular PC Engine. However, the SuperGrafx is backwards compatible with all PC Engine software in both HuCard and CD-ROM² format, bringing the compatible software total up to nearly 700. Due to its commercial failure, none of the added hardware enhancements were carried over to the later PC Engine Duo consoles.

Hardware

Compared to the PC Engine, the SuperGrafx has four times the amount of working RAM for the main CPU and a second video chip with its own video RAM. Also included is a priority controller chip, which allows the output of both video chips to be combined in various ways. The SuperGrafx has support for two independently scrolling background layers, like the Mega Drive, as opposed to the PC Engine's single layer.

It is a very common misconception[4] that the extra video hardware capabilities were taxing on the system's CPU, and is often cited as the main reason few games were developed for the system. In reality, despite having the same CPU as the PC Engine, the SuperGrafx is more than capable of keeping up with the new graphics enhancements, as the majority of the workload is handled by the VDPs.

SuperGrafx with Super CD-ROM²

One accessory of note was the "Power Console", designed to add a full flight yoke, throttle and keypad to the SuperGrafx, sliding over the entire console. Besides a prototype, no Power Consoles were ever produced.

Since the SuperGrafx was produced and marketed as an upgraded PC Engine model rather than as a new platform, it was backwards compatible with standard PC Engine HuCards in addition to its own. However, SuperGrafx-specific HuCards were expensive compared to standard HuCards, in some cases approaching as much as $110 USD at retail.

The SuperGrafx is also compatible with the CD-ROM² System add-on (via the ROM² Adaptor), as well as the Super CD-ROM² add-on. No CD-ROM² format games were produced that took advantage of the SuperGrafx's added capabilities.

Technical specifications

Processing

It contained both a CPU and a GPU.

The CPU was an 8-bit HuC6280A, a modified 65SC02, running at 1.79, or 7.16 MHz (switchable by software). Features included 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. The GPU was a multiple graphics processor setup composed of one 16-bit HuC6260 Video Color Encoder (VCE), two 16-bit HuC6270A Video Display Controllers (VDCs), and one HuC6202 Video Priority Controller. The HuC6270A featured Port-based I/O similar to the TMS99xx VDP family.

Memory

There was 32KB of work RAM and 128KB (64KB per HuC6270A VDC) Video RAM.

Display

The X (Horizontal) Resolution was variable, maximum of 565 (programmable to 282, 377 or 565 pixels, or as 5.37mhz, 7.159mhz, and 10.76mhz pixel dot clock)[5] 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, 336, or 512 pixels in display width for each of the three modes.[6] The Y (Vertical) Resolution was also variable, maximum of 242 (programmable in increments of 1 scanline).

Color had a depth of 9 bits with 512 colors available with 482 (241 background, 241 sprite) on screen. There were 32 palettes (16 for background tiles, 16 for sprites), with 16 colors per palette. 128 sprites were simultaneously displayable with sizes of: 16×16, 16×32, 16×64, 32×16, 32×32, 32×64. 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 dual HuC6270A VDCs are capable of displaying 2 sprite layers (1 each). Sprites could be placed either in front of or behind background tiles. Each layer can display 16 sprites or 256 sprite pixels per scanline, giving the combined sprite per scanline limit of 32 sprites or 512 sprite pixels.

Tiles were 8x8 with each background tile able to 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.

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.

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.

Software media

Software was distributed in two manners HuCard and CD-ROM². HuCard was a thin, card-like game media that served as the PC Engine's proprietary software storage format. The SuperGrafx was backwards compatible with all legacy HuCards in addition to its own. The labels on SuperGrafx HuCards were upside-down relative to standard HuCards; A standard HuCard will read upside down on a SuperGrafx, while its own are right-side-up. CD-ROM² was the SuperGrafx is compatible with all CD-ROM² System titles, including Super CD-ROM² and Arcade CD-ROM², provided the console is connected to a CD-ROM drive add-on and has the required System Card. No CD-ROM² games were produced specifically for the SuperGrafx.

Input/Output

I/O was provided by: one HuCard cartridge connector, EXT-BUS expansion connector (for Super CD-ROM², Tennokoe 2, RAU-30, etc.), Standard mini-DIN gamepad connector, Enhanced I/O port with 8 output and 4 input pins for the unreleased Power Console peripheral, 5-pin DIN A/V connector with composite video and stereo audio output only, Power adapter jack, and Compatibility mode (PC-Engine or SuperGrafx) switch on back of unit.

Peripherals

The SuperGrafx is compatible with all standard PC Engine input devices, such as the TurboPad and the Multitap.

The ROM² Adaptor (RAU-30) was an adapter released in Japan on April 20, 1990[7] that allows the SuperGrafx unit to be connected into CD-ROM² System's Interface Unit. This was not required for the later Super CD-ROM² System add-on.

Power Console (PI-PD7)[8] was an unreleased cockpit-sized controller that attaches onto the SuperGraph unit itself, connecting via the expansion port on the front side. The peripheral would've added numerous control options such as an eight-way joystick, four action buttons, a flight yoke with two triggers (one on each handle), a throttle lever, a jog dial, three mode switches, an LCD panel, an LED indicator, four additional controller ports and a numerical keypad. The Power Console was scheduled to be released in Spring 1990 with a suggested retail price of 59,800 yen, but was never released due to its high production cost and the poor sales of the SuperGrafx itself.[9][10]

Software catalog

Retail games

A total of six HuCards were released for the PC Engine SuperGrafx.

Darius Plus is the only retail game that is dual-compatible with standard PC Engine consoles in addition to the SuperGrafx. As such, it was the only game to carry the PC-SG mark to denote such a feature.[11]

Premium

A special version of Darius Plus, titled Darius Alpha was also released as a sweepstakes giveaway. This product was given away to certain customers in late 1990 who filled out the survey card that came with Darius Plus or by sending a proof of purchase from the manual of Super Darius (the game's CD-ROM² version) to NEC Avenue during a period between September 21 through November 16. Like the retail version of the game, Darius Alpha is a dual-compatible PC-SG HuCard. Only 800 copies of Darius Alpha were produced and distributed, making it a sought-after collector's item.[12]

Unreleased

  • Forgotten Worlds - Announced only. Eventually released in Super CD-ROM² format.
  • Galaxy Force II
  • Strider Hiryu - Announced in 1990. The SuperGrafx version was canceled and development of NEC Avenue's Strider port shifted to other formats before it was eventually released as an Arcade CD-ROM² game in 1994.[13]

References

  1. ↑ "PC-Engine". www.pc-engine.co.uk.
  2. ↑ Harris, Steve (July 1989). "Cover Story - Next Generation Gaming". Electronic Gaming Monthly. Vol. 1 no. 2. pp. 31–32.
  3. ↑ "Darius Alpha Review for Super Grafx (1990) - Defunct Games". www.defunctgames.com.
  4. ↑ "101 PC Engine Secrets". nfggames.com.
  5. ↑ "MagicEngine :: View topic - Screen Dimension Test program". forums.magicengine.com.
  6. ↑ "Login". www.pcenginefx.com.
  7. ↑ "PC-Engine". www.pc-engine.co.uk.
  8. ↑ "PC Engine SuperGrafx promotional pamphlet". ゲーム広告資料館 [Game Advertisement Museum] (in Japanese).
  9. ↑ "PCエンジンSG周辺機器早くも登場!!" [New PC Engine SG peripheral coming soon!]. Famicom Tsūshin (in Japanese). 4 (23). 1989-10-11.
  10. ↑ "PC-ENGINE最終兵器" [The PC Engine's Ultimate Weapon]. ゲームパッド地下秘密 [The Underground Secrets of the Gamepad].
  11. ↑ "スーパーPCエンジンファン" [Super PC Engine Fan] (in Japanese). Vol. 1. Tokuma Shoten Intermedia. January 15, 1994.
  12. ↑ "ダライアスプラス ( ゲーム ) - ゲーム広告資料館 - Yahoo!ブログ" (in Japanese).
  13. ↑ "Prescreen". Edge. July 1994. p. 38.
  • pcenginefx - Enthusiast-run site for NEC video game consoles.
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