View source for Sega System 1

{{ConsoleBob
| logos=
| consoleimage=System1 PCB1.jpg
| imgwidth=320
| name=
| maker=[[Sega]]
| processor=[[Zilog Z80]]
| releases={{releasesArcade
| system_date_jp_1=1982-12
| system_type_jp_1=prototype
| system_date_world=1983-07
}}
}}
The '''Sega System 1''' (セガ システム 1) is an [[arcade]] platform officially debuted by [[Sega]] in 1983,{{ref|[http://sega.jp/fb/segahard/sc3000/gallery.html 1983 Timeline (Sega Corporation)]}} based on earlier 1982 prototype hardware. It is a [[Z80]]-based platform and the first in the decade-long "[[:Category:Sega System series|System]]" series of arcade boards.

The System 1 was a relatively popular arcade board for its day, supported not only by Sega, but by Japanese developers [[Coreland]] and [[VIC Tokai]] between 1983 and 1987. In 1985 it was succeeded by the slightly more powerful [[Sega System 2]] board, though new games were released for both systems concurrently. Many of the System 1's games were ported to the [[SG-1000]] and [[Sega Master System]] consoles.

==Technical specifications==
===System 1===
{{multicol|
* Board composition: One board
:* Master clock rate: 19.99982 MHz{{ref|[https://github.com/mamedev/mame/blob/master/src/mame/drivers/system1.cpp Sega System 1 / System 2 (MAME)]}}
* Main CPU: [[Zilog Z80]] @ 4&nbsp;MHz (8/16-bit instructions, 0.58&nbsp;[[wikipedia:Instructions per second|MIPS]])
* Sound CPU: Zilog Z80 @ 4&nbsp;MHz (8/16-bit instructions, 0.58&nbsp;MIPS)
* [[wikipedia:Sound chip|Sound chips]]: Sega [[SN76489|SN76496]] @ 4&nbsp;MHz, Sega SN76496 @ 2&nbsp;MHz
* [[wikipedia:Microcontroller|MCU]]: Intel 8751{{ref|[https://github.com/mamedev/mame/blob/master/src/mame/drivers/system1.cpp Sega System 1 / System 2 (MAME)]}}
}}

====Graphics====
{{multicol|
* Graphics chipset:{{ref|[https://github.com/mamedev/mame/blob/master/src/mame/drivers/system1.cpp Sega System 1 / System 2 (MAME)]}}
:* Sega 315-5011 sprite line comparator: 16‑bit line buffer RAM (14.999865 MHz, 29.99973 MB/s),{{fileref|Regulus System1 US Manual.pdf|page=8}}{{fileref|HangOn Schematics.pdf|page=4}} 9.99991 MHz sprite line buffer render/pixel clock, 4.999955 MHz sprite line buffer scan/erase clock{{ref|[https://github.com/mamedev/mame/blob/master/src/mame/drivers/system1.cpp Sega System 1 / System 2 (MAME)]}}{{intref|Sega Pre-System 16 hardware notes (2004-03-29)}}
:* Sega 315-5012 sprite generator
:* Sega 315-5049 tilemap generator
* Video resolution: 256×224 (active), 640×260 ([[wikipedia:Overscan|overscan]]){{ref|[https://github.com/mamedev/mame/blob/master/src/mame/drivers/system1.cpp Sega System 1 / System 2 (MAME)]}}
:* Scanlines: 260 (224 active, 36 [[wikipedia:Vertical blanking interval|VBlank]])
:* [[Pixel]] clock rate: 9.99991 MHz (3.446099 MHz active, 6.55381 MHz [[wikipedia:Horizontal blanking interval|HBlank]]/VBlank)
:* Refresh rate: 60.0952&nbsp;Hz ([[wikipedia:Vertical sync|VSync]])
* [[Palette|Color palette]]: 4096{{ref|[https://github.com/mamedev/mame/blob/master/src/mame/video/system1.cpp System1 / System 2 video hardware (MAME)]}}
:* Colors on screen: 2048{{ref|[https://github.com/mamedev/mame/blob/master/src/mame/drivers/system1.cpp Sega System 1 / System 2 (MAME)]}}
* [[Sprite]] plane: Line buffer, double buffering, 16 colors per sprite, sprite flipping, hardware collision detection{{ref|[https://github.com/mamedev/mame/blob/master/src/mame/video/system1.cpp System1 / System 2 video hardware (MAME)]}}{{ref|[https://github.com/mamedev/mame/blob/master/src/mame/drivers/system1.cpp Sega System 1 / System 2 (MAME)]}}
:* Sprites on screen: 128 sprites (2 KB sprite attributes, 16 bytes per sprite){{intref|Sega Pre-System 16 hardware notes (2004-03-29)}}
:* Sprite sizes: 8×8 to 256×224 [[texel]]s
:* Line buffer [[fillrate]]: 9.99991 [[Pixel|MPixels/s]]
:* Sprites per scanline: 32 sprites, 640 texels
* Background planes: 2 [[Tile Layer|tilemap]] layers (1 static, 1 scrolling), 8×8 tiles{{ref|[https://github.com/mamedev/mame/blob/master/src/mame/video/system1.cpp System1 / System 2 video hardware (MAME)]}}{{ref|[https://github.com/mamedev/mame/blob/master/src/mame/drivers/system1.cpp Sega System 1 / System 2 (MAME)]}}
:* Tilemap sizes: 256×256 for both planes
}}

====Memory====
{{multicol|
* Memory: 155.75 [[Byte|KB]] (52 KB main, 93.75 KB video, 10 KB sound)
* [[RAM]]: 19.5&nbsp;KB{{ref|[https://github.com/mamedev/mame/blob/master/src/mame/drivers/system1.cpp Sega System 1 / System 2 (MAME)]}}
:* Main: 4&nbsp;KB (8-bit, 4 MHz, 4 MB/s){{fileref|Regulus System1 US Manual.pdf|page=14}}
:* [[VRAM|Video]]: 13.5&nbsp;KB [[SRAM]] (4&nbsp;KB video, 2&nbsp;KB sprite attributes, 1.5 KB sprite line buffers,{{ref|[https://github.com/mamedev/mame/blob/master/src/mame/video/system1.cpp System1 / System 2 video hardware (MAME)]}}{{intref|Sega Pre-System 16 hardware notes (2004-03-29)}} 2&nbsp;KB palette, 4&nbsp;KB collision)
:* Sound: 2&nbsp;KB
* [[ROM]]: 136.25 KB
:* Main: 48 KB
:* Video: 80.25 KB (48 KB tiles, 32 KB sprites, 256 [[byte]]s palette)
:* Sound: 8 KB
}}

===Prototype===
''[[Super Locomotive]]'' in 1982 ran on prototype arcade hardware that was very similar to the Sega System 1 later released in 1983. ''Super Locomotive'' had largely identical specifications, but with the following differences:{{ref|[https://github.com/mamedev/mame/blob/master/src/mame/drivers/suprloco.cpp Super Locomotive (MAME)]}}{{ref|[https://github.com/mamedev/mame/blob/master/src/mame/video/suprloco.cpp Super Locomotive video hardware (MAME)]}}{{ref|1=[http://www.system16.com/hardware.php?id=688 Sega Z80 Based Hardware (System 16)]}}

====Graphics====
{{multicol|
* Graphics chipset:
:* Sega 315-5011 sprite line comparator: 16‑bit line buffer RAM (11.79648 MHz, 23.59296 MB/s), 7.86432 MHz sprite line buffer render clock, 3.93216 MHz sprite line buffer scan/erase/pixel clock{{intref|Sega Pre-System 16 hardware notes (2004-03-29)}}
* Video resolution: 248×224 (active), 256×256 (overscan)
:* [[Pixel]] clock rate: 3.93216&nbsp;MHz
:* Refresh rate: 60&nbsp;Hz
* Color palette: 1568
:* Colors on screen: 768
* [[Sprite]] plane:
:* Sprites on screen: 32 sprites (512 bytes sprite attributes, 16 bytes per sprite), 64 sprites with raster interrupt
:* Sprite sizes: 8×8 to 248×224 [[texel]]s
:* Line buffer [[fillrate]]: 7.86432 [[Pixel|MPixels/s]]
:* Sprites per scanline: 32 sprites, 512 texels
}}

====Memory====
{{multicol|
* Memory: 113.3125 [[Byte|KB]] (50 KB main, 53.3125 KB video, 10 KB sound)
* [[RAM]]: 7.78125 KB
:* Main: 2 KB
:* Video: 3.78125 KB [[SRAM]] (1.75 KB video, 512 [[byte]]s sprite atttributes, 1.5 KB sprite line buffers, 32 bytes scrolling)
:* Sound: 2 KB
* [[ROM]]: 105.53125 KB
:* Main: 48 KB
:* Video: 49.53125 KB (48 KB graphics, 1.53125 KB palette)
:* Sound: 8 KB
}}

==List of games==
Note that ''[[Super Locomotive]]'' is listed as a System 1 game for using similar technology, but was not distributed on a System 1 board. 
{{BulletPointGameList|SYS1}}

==Production credits==
{{creditstable|
*[[Hideki Sato]]
| source=Developer mentions{{ref|https://web.archive.org/web/20210205150032/https://www.4gamer.net/games/999/G999905/20210126043/}}
| console=SYS1
}}

==Photo gallery==
<gallery>
System1 PCB1.jpg|PCB 1
System1 PCB2.jpg|PCB 2
</gallery>

==References==
<references/>

{{Sega Arcade Boards}}
[[Category:Sega System series]]