Sega System 16

Sega System 16

Manufacturer: Sega

Release	Date	RRP	Code

The Sega System 16 is an arcade board released by Sega in 1985 as a 16-bit successor to the Sega System 1. Throughout its lifespan, there would be around forty games released on this hardware, making it one of Sega's most successful hardware designs. It was produced in three variants, the Pre-System 16, System 16A and System 16B, though the only differences between the three are clock speeds.

The System 16 is the home to many of Sega's most successful franchises, including Shinobi, Fantasy Zone, Altered Beast and Golden Axe. It popularised the use of the Motorola 68000 CPI and Zilog Z80 combo, something which was copied for Capcom's successful CPS-1 and CPS-2 boards (among other arcade systems of the day), as well as most notably, the Sega Mega Drive.

In order to prevent piracy, as well as illegal bootleg games, many System 16 boards used an encryption system. A Hitachi FD1094 chip, containing the main CPU as well as the decryption key, was used in place of a regular CPU.

Though Pre-System 16, System 16A and System 16B are the three most recognised variants of the hardware, there is technically a fourth, dubbed "System 16C" which was used by the 2008 release of Fantasy Zone II DX: The Tears of Opa-Opa. Fantasy Zone II DX arrived almost a decade and a half after the System 16 hardware was discontinued, however its real arcade release means that System 16C specifications may belong to the Sega System 16 series. Fantasy Zone II DX needs more RAM than any of the other System 16 boards can offer, but the game adhered to other restrictions of the hardware.

Technical Specifications

System 16A

Board Composition: Top PCB, Bottom PCB^[1]
Main CPU: Hitachi FD1094 (Motorola 68000) @ 10 MHz (16-bit & 32-bit instructions @ 1.75 MIPS)
Main MCU: Intel i8751 @ 8 MHz (8-bit instructions @ 8 MIPS, 1 instruction per cycle)
Sound CPU: NEC uPD780C-1 (Zilog Z80 clone) @ 4 MHz
Sound MCU: Intel i8048 @ 6 MHz (8-bit instructions @ 6 MIPS)
FM Sound Chip: Yamaha YM2151 @ 4 MHz (8 FM synthesis channels)
PCM sound chip: NEC uPD7751 @ 6 MHz
- ADPCM Channels: 3
- Audio Bit Depth: 8-bit
GPU Chipset: 315-5011 sprite line comparator, 315-5012 sprite generator, 2× 315-5049 tilemap chips, 315-5107 & 315-5108 display timers, 315-5143 & 315-5144 sprite chips, 315-5149 video mixer
- Clock Rate Performance: 12.5874 MHz sprite line buffer render clock, 6.2937 MHz sprite line buffer scan/erase & pixel clock
RAM: 77 KB Static RAM (22 KB top PCB, 55 KB bottom PCB)^[1]
- Main CPU: 74 KB (32 KB tiles, 4 KB text, 2 KB sprites, 4 KB palette, 16 KB I/O, 16 KB NVRAM)
- Sound CPU: 2 KB
Display Resolution: Progressive scan
- Horizontal: 320×224 (display), 342×262 (overscan)
- Vertical: 224×320 (display), 262×342 (overscan)
Color Palette: 98,304
- 15-bit RGB high color depth (32,768 colors) and 1-bit shadow & highlight that triples up to 98,304 colors
Colors on Screen: 4096 (unique colors) to 6144 (with shadow & highlight)
Graphical Planes:
- 1 sprite layer
- 1 text layer
- 2 tile layers (row & column scrolling, 8×8 tiles)
Sprite Capabilities: Dual line buffers, double buffering, 128 on-screen sprites
- Fillrate per Scanline: 800 sprite pixels/texels (800.75 sprite processing ticks) per scanline
- Sprites per Scanline: 100 sprites per scanline
- Colors per Sprite: 16
- Sprite Sizes: 8 to 256 pixels width, 8 to 256 pixels height

System 16B

System 16B included the following upgrades in 1986:

Sound CPU: Zilog Z80 @ 5 MHz (8-bit & 16-bit instructions @ 0.725 MIPS)
PCM Sound Chip: NEC uPD7751 ADPCM Decoder @ 640 kHz
- ADPCM Channels: 8
- Audio Bit Depth: 9-bit
- Other Features: 8 kHz sampling rate, up to 128 KB audio ROM and 256 samples
GPU Chipset: 315-5196 sprite generator, 315-5197 tilemap generator, 315-5213 sprite chip, 315-5248 & 315-5250 math chips
- Sprite Capabilities: Sprite scaling
RAM: 102 KB Static RAM^[1]
- Main CPU: 90 KB (2 KB sprites, 4 KB palette, 64 KB tiles, 4 KB text, 16 KB work RAM)
- Sound CPU: 2 KB
- Other RAM: 10 KB

System 16C

There was also a System 16C, which included the following upgrade over System 16B:

RAM: 332 KB (102 KB Static RAM)^[1]
- Main CPU: 330 KB (2 KB sprites, 4 KB palette, 64 KB tiles, 4 KB text, 256 KB work RAM)
- Sound CPU: 2 KB

Gallery

Pre-System 16

Motherboard

Sega System 16A

Motherboard (side 1)
Motherboard (side 2)

Sega System 16B

Motherboard

List of Games