The SuperGrafx video game console is an upgraded version of NEC's popular PC Engine (North America: TurboGrafx-16) system. At first it was known as the PC-Engine 2 — which was purported to be a true 16-Bit system with improved graphics and audio capabilities, not expected to see release until 1990. However the final machine was named SuperGrafx, was released earlier than expected, in late 1989, only provided modestly enhanced graphics over the original PC-Engine, had audio that was the same as the PC-Engine and no 16-bit CPU, just the same one as the PC-Engine.
The enhancements SuperGrafx did have: compared to the PC-Engine, SuperGrafx has four times the amount of work RAM for the main CPU, a second video chip with its own video RAM, and a priority controller chip that allowed the output of both video chips to be combined in various ways. SuperGrafx had support for two independently scrolling background layers, like the Sega Megadrive/Genesis, instead of the PC-Engine's single layer.
The SuperGrafx was not well received, due to a lack of software written to support its enhanced abilities; only 7 titles were ever released. There were no CD, SCD, or ACD games written that took advantage of the SuperGrafx platform. Game software was also very expensive, with games approaching 110 (USD). However, the SuperGrafx can play PCE HuCards, PCE CDs, PCE Super CDs, PCE Arcade CDs, and the native SuperGrafx HuCards. These titles combined totals to a very respectable library of near 700 titles.
In addition, its single 8-bit CPU had a heavy workload managing the extra video hardware.
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.
- CPU: 8-bit HuC6280A, a modified 65SC02 running at 1.79 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 multiple graphics processor setup. 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.
- Horizontal resolution: variable, maximum of 512 (programmable to 256, 352, or 512 pixels)
- Vertical resolution: variable, maximum of 242 (programmable in increments of 1 scanline)
- The majority of SuperGrafx games use 256×240.
- Depth: 8-bit
- Colors available: 513
- Colors onscreen: 482 (241 background, 241 sprite)
- Palettes: 32 (16 for background tiles, 16 for sprites)
- Colors per palette: 16
- Simultaneously displayable: 128
- 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 dual HuC6270A VDCs are capable of displaying 2 sprite layers (1 each). Sprites could be placed either in front of or behind background 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 dual HuC6270A VDCs were capable of displaying 2 background layers (1 each).
- Work RAM: 32KB
- Video RAM: 128KB (64KB per HuC6270A VDC)
- Six PSG audio channels, programmable through the HuC6280A CPU.
- Each channel had a frequency of 111.87 kHz (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.).
- The first two audio channels (1 and 2) were capable of LFO when channel #2 was used to modulate channel #1. This was used to achieve FM-like sound qualities.
- 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).
- 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 TurboGrafx-16.
- HuCard: A thin, card-like game media. The largest Japanese HuCard games were up to 20Mbit in size. In addition to its own HuCard games, the SuperGrafx was backward compatible with all PC Engine HuCard games. The labels on SuperGrafx HuCards were upside-down relative to PC Engine HuCards; A PC Engine HuCard will read upside down on a SuperGrafx, while its own are right-side-up.
- CD: The SuperGrafx was compatible with the PC Engine Super CD-ROM² unit, and could play all PC-Engine CD games with it attached. There were no CDs produced especially for the SuperGrafx.
- HuCard cartridge connector.
- EXT-BUS expansion connector. (for CD-ROM, Tennokoe 2, RAU-30, etc.)
- Standard mini-DIN gamepad connector.
- Enhanced I/O port with 8 output and 4 input pins.
- 5-pin DIN A/V connector with composite video and stereo audio output only.
- Power adapter jack.
- Compatibility mode (PC-Engine or SuperGrafx) switch on back of unit.
- The enhanced I/O port was designed for a multiple-input perhipheral that was shown in several game magazines but never released commercially.
- RAU-30 adapter Connects SuperGrafx to IFU-30 CD-ROM interface tray, as the SuperGrafx won't fit due to its unusual shape.
All SuperGrafx releases were on SHuCard format.
Backwards Compatible with PC Engine
- Darius Alpha - improved graphics when played on SuperGrafx
- Darius Plus - improved graphics when played on SuperGrafx
- Magic Engine - Commercial TurboGrafx-16/PC-Engine/SuperGrafx emulator.
- Mednafen - GPL'd Multi-System Emulator that supports PC Engine(TurboGrafx 16) and SuperGrafx.