Difference between revisions of "Dot clock rates"

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(Game Gear video has same dot clock rate as Master System)
(restore CPS3, with correct information this time)
 
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! Frequency || Exact frequency || PAR || Exact PAR || Devices
 
! Frequency || Exact frequency || PAR || Exact PAR || Devices
 
|-
 
|-
| 1.02 MHz || 315/308 MHz || 1.50 || 3:2 || Apple II (GR; each line repeated four times)
+
| 1.02 MHz || 315/308 MHz || 1.500 || 3:2 || Apple II (GR; each line repeated four times)
 
|-
 
|-
| 3.58 MHz || 315/88 MHz || 1.71 || 12:7 || Devices with 1 pixel per NTSC subcarrier period: Atari 2600, Atari 7800, Intellivision
+
| 3.58 MHz || 315/88 MHz || 1.714 || 12:7 || Devices with 1 pixel per NTSC subcarrier period: Atari 2600, Atari 7800, Intellivision
 
|-
 
|-
| 5.00 MHz || 5/1 MHz || 1.22 || 27:22 || Atari ''Missile Command''<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/missile.cpp missile.cpp] from MAME</ref> and ''Crystal Castles'' hardware<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/ccastles.cpp ccastles.cpp] from MAME</ref>, Stern ''Berzerk''/''Frenzy'' hardware<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/berzerk.cpp berzerk.cpp] from MAME</ref> (all 256px)
+
| 4.61 MHz || 576/125 MHz || 1.332 || 1875:1408 || Konami GX400 family (a.k.a. ''Nemesis'' and Bubble System) (256px)<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/nemesis.cpp nemesis.cpp] from MAME; this information had been included in the MAME driver code as an arithmetic calculation long before the modern <code>set_raw</code> function was called</ref>
 
|-
 
|-
| 5.37 MHz || 945/176 MHz || 1.14 || 8:7 || The 256px display of the [[wikipedia:TMS9918|TMS9918]] (TI-99/4A, ColecoVision, MSX, and SG-1000), its descendants (MSX2, Master System, Genesis, Game Gear<ref>Game Gear divides a [https://www.ebay.com/itm/1x-32-2159-T-Q-C-MHz-KHz-Crystal-Oscillator-Quartz-Japan-OSC-SEGA-Game-Gear-/272604410744 32.2159 MHz crystal] by 6 to produce the dot clock. This frequency is 9 times NTSC color burst, and each of three subpixels in each pixel occupies 6 dots. [http://members.optusnet.com.au/eviltim/ggrgb/ggrgb.html Evil Tim's SCART mod] produces, which gives centered in the screen with the same size as a Super Game Boy picture.</ref>), and other VDPs inspired by it (NES, TurboGrafx-16,<ref>[http://archaicpixels.com/index.php/HuC6260 HuC6260 - Archaic Pixels]</ref> Super NES), and 256px mode of the original PlayStation<ref name="ryphecha_ps1">The PS1 divides a 15 times NTSC (53.69 MHz) crystal by 10, 8, 7, 5, or 4 [http://forum.fobby.net/index.php?t=msg&&th=1117&goto=4132#msg_4132 Post by Ryphecha on Mednafen forum]</ref>
+
| 5.00 MHz || 5/1 MHz || 1.227 || 27:22 || Atari ''Missile Command''<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/missile.cpp missile.cpp] from MAME</ref> and ''Crystal Castles'' hardware<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/ccastles.cpp ccastles.cpp] from MAME</ref>, Stern ''Berzerk''/''Frenzy'' hardware<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/berzerk.cpp berzerk.cpp] from MAME</ref> (all 256px)
 
|-
 
|-
| 5.59 MHz || 16777216/3 Hz || 1.10 || 6328125:5767168 || Nintendo DS (256px) is the ~33.5 MHz (apparently 2<sup>25</sup> Hz) master clock divided by 6<ref>GBATEK by Martin Korth</ref>
+
| 5.37 MHz || 945/176 MHz || 1.143 || 8:7 || The 256px display of the [[wikipedia:TMS9918|TMS9918]] (TI-99/4A, ColecoVision, MSX, and SG-1000), its descendants (MSX2, Master System, Genesis, Game Gear<ref>Game Gear divides a [https://www.ebay.com/itm/1x-32-2159-T-Q-C-MHz-KHz-Crystal-Oscillator-Quartz-Japan-OSC-SEGA-Game-Gear-/272604410744 32.2159 MHz crystal] by 6 to produce the dot clock. This frequency is 9 times NTSC color burst, and each RGB pixel is 6 dots, divided into three 2-dot subpixels. [http://members.optusnet.com.au/eviltim/ggrgb/ggrgb.html Evil Tim's SCART mod] produces 240p RGB output centered in the screen with the same size as a Super Game Boy picture.</ref>), and other VDPs inspired by it (NES, TurboGrafx-16,<ref>[http://archaicpixels.com/index.php/HuC6260 HuC6260 - Archaic Pixels]</ref> Super NES), and 256px mode of the original PlayStation<ref name="ryphecha_ps1">The PS1 divides a 15 times NTSC (53.69 MHz) crystal by 10, 8, 7, 5, or 4 [http://forum.fobby.net/index.php?t=msg&&th=1117&goto=4132#msg_4132 Post by Ryphecha on Mednafen forum]</ref>
 
|-
 
|-
| 6.00 MHz || 6/1 MHz || 1.02 || 45:44 || Data East ''Lock'n Chase''/''BurgerTime'' family (240 or 256px)<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/btime.cpp btime.cpp] from MAME</ref>, DECO Cassette System (256px)<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/decocass.cpp decocass.cpp] from MAME</ref>, and ''BreakThru'' family (240px)<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/brkthru.cpp brkthru.cpp] from MAME</ref><br />Technos ''Double Dragon'' hardware,<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/ddragon.cpp ddragon.cpp] from MAME</ref> SNK pre-Neo Geo 68000-based hardware,<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/snk68.cpp snk68.cpp] from MAME</ref> Taito ''Arkanoid''<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/arkanoid.cpp arkanoid.cpp] from MAME</ref> and ''Bubble Bobble''<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/bublbobl.cpp bublbobl.cpp] from MAME</ref> hardware, Jaleco Mega System 1-A<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/megasys1.cpp megasys1.cpp] from MAME. The same pixel clock is possible but unverified for the other Mega System 1 variants.</ref> (all 256px)<br />Konami GX<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/konamigx.cpp konamigx.cpp] from MAME</ref> and pre-GX (''Mystic Warriors'') family<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/mystwarr.cpp mystwarr.cpp] from MAME</ref> (288px)<br />Neo Geo MVS (320px)<ref>[https://github.com/mamedev/mame/blob/master/src/mame/video/neogeo_spr.h video/neogeo_spr.h] from MAME. Many Neo Geo games are designed around a safe area approximately 304 pixels wide.</ref>
+
| 5.59 MHz || 16777216/3 Hz || 1.097 || 6328125:5767168 || Nintendo DS (256px) is the ~33.5 MHz (apparently 2<sup>25</sup> Hz) master clock divided by 6<ref>GBATEK by Martin Korth</ref>
 
|-
 
|-
| 6.04 MHz || 6048/1001 MHz || 1.02 || 65:64 || Neo Geo AES (320px)<ref>384 pixels per standard 227.5-cycle scanline period. See [//forums.nesdev.com/viewtopic.php?p=179127#p179127 NESdev posts by TmEE and psycopathicteen]. TODO: Verify whether the timing differences from MVS are noted anywhere in the MAME source code.</ref>
+
| 6.00 MHz || 6/1 MHz || 1.023 || 45:44 || Data East ''Lock'n Chase''/''BurgerTime'' family (240 or 256px)<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/btime.cpp btime.cpp] from MAME</ref>, DECO Cassette System (256px)<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/decocass.cpp decocass.cpp] from MAME</ref>, and ''BreakThru'' family (240px)<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/brkthru.cpp brkthru.cpp] from MAME</ref><br />Technos ''Double Dragon'' hardware,<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/ddragon.cpp ddragon.cpp] from MAME</ref> SNK pre-Neo Geo 68000-based hardware,<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/snk68.cpp snk68.cpp] from MAME</ref> Taito ''Arkanoid''<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/arkanoid.cpp arkanoid.cpp] from MAME</ref> and ''Bubble Bobble''<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/bublbobl.cpp bublbobl.cpp] from MAME</ref> hardware, Jaleco Mega System 1-A<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/megasys1.cpp megasys1.cpp] from MAME. The same pixel clock is possible but unverified for the other Mega System 1 variants.</ref> (all 256px)<br />Konami GX<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/konamigx.cpp konamigx.cpp] from MAME</ref> and pre-GX (''Mystic Warriors'') family<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/mystwarr.cpp mystwarr.cpp] from MAME</ref> (288px)<br />Neo Geo MVS (320px)<ref>[https://github.com/mamedev/mame/blob/master/src/mame/video/neogeo_spr.h video/neogeo_spr.h] from MAME. Many Neo Geo games are designed around a safe area approximately 304 pixels wide.</ref>
 
|-
 
|-
| 6.09 MHz || 1071/176 MHz || 1.01 || 120:119 || Nintendo 64 (320px)<ref>[http://www.assemblergames.com/forums/showthread.php?42764-Direct-HDMI-output-for-N64-%28and-other-consoles%29 assemblergames forum post]</ref><ref>[http://www.datasheetarchive.com/dlmain/Datasheets-17/DSA-326918.pdf MX8350 clock generator]</ref><ref>[https://github.com/mamedev/mame/blob/master/src/mame/includes/n64.h includes/n64.h] from MAME. Note the mention of quarter-pixel scanline length in [https://github.com/mamedev/mame/blob/master/src/mame/drivers/n64.cpp n64.cpp]; divide the given <code>DACRATE_NTSC</code> by 8 to obtain the result here.</ref>
+
| 6.04 MHz || 6048/1001 MHz || 1.016 || 65:64 || Neo Geo AES (320px)<ref>384 pixels per standard 227.5-cycle scanline period. See [//forums.nesdev.com/viewtopic.php?p=179127#p179127 NESdev posts by TmEE and psycopathicteen]. TODO: Verify whether the timing differences from MVS are noted anywhere in the MAME source code.</ref>
 
|-
 
|-
| 6.14 MHz || 135/22 MHz || 1.00 || 1:1 || Rec. 601 defines the NTSC picture such that this is square on 4:3 monitors
+
| 6.05 MHz || 756/125 MHz || 1.015 || 625:616 || Namco NB-1/NB-2 family (288px)<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/namconb1.cpp namconb1.cpp] from MAME: same divisor and dot counts that originated from ''Galaxian,'' except with a slower crystal (48.384MHz)</ref>
 
|-
 
|-
| 6.14 MHz || 768/125 MHz || 1.00 || 5625:5632 || 48000 kHz (DAT and DVD audio rate) * 128<ref name="towcrystals" /> approximates square pixels to within 1 part in 800<br />Irem M52 (''Moon Patrol'') (240px)<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/m52.cpp m52.cpp] from MAME</ref><br />Namco ''Pac-Man''<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/pacman.cpp pacman.cpp] from MAME</ref>/''Galaxian''<ref>[https://github.com/mamedev/mame/blob/master/src/mame/video/galaxian.cpp video/galaxian.cpp] from MAME. The "6MHz" mentioned in some comments is only an approximation.</ref> hardware and derivatives such as ''Pengo'' (288px)<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/pengo.cpp pengo.cpp] from MAME</ref><br />Namco ''Super Pac-Man'' family,<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/mappy.cpp mappy.cpp] from MAME</ref> System 86,<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/namcos86.cpp namcos86.cpp] from MAME</ref> 1,<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/namcos1.cpp namcos1.cpp] from MAME</ref> 2,<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/namcos2.cpp namcos2.cpp] from MAME</ref> and ND-1<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/namcond1.cpp namcond1.cpp] from MAME</ref> (all 288px)
+
| 6.09 MHz || 1071/176 MHz || 1.008 || 120:119 || Nintendo 64 (320px)<ref>[http://www.assemblergames.com/forums/showthread.php?42764-Direct-HDMI-output-for-N64-%28and-other-consoles%29 assemblergames forum post]</ref><ref>[http://www.datasheetarchive.com/dlmain/Datasheets-17/DSA-326918.pdf MX8350 clock generator]</ref><ref>[https://github.com/mamedev/mame/blob/master/src/mame/includes/n64.h includes/n64.h] from MAME. Note the mention of quarter-pixel scanline length in [https://github.com/mamedev/mame/blob/master/src/mame/drivers/n64.cpp n64.cpp]; divide the given <code>DACRATE_NTSC</code> by 8 to obtain the result here.</ref>
 
|-
 
|-
| 6.25 MHz || 25/4 MHz || 0.98 || 54:55 || Sega X-Board (320px)<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/segaxbd.cpp segaxbd.cpp] from MAME</ref>
+
| 6.14 MHz || 135/22 MHz || 1.000 || 1:1 || Rec. 601 defines the NTSC picture such that this is square on 4:3 monitors
 +
|-
 +
| 6.14 MHz || 768/125 MHz || 0.999 || 5625:5632 || 48000 kHz (DAT and DVD audio rate) * 128<ref name="towcrystals" /> approximates square pixels to within 1 part in 800<br />Irem M52 (''Moon Patrol'') (240px)<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/m52.cpp m52.cpp] from MAME</ref><br />Namco ''Pac-Man''<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/pacman.cpp pacman.cpp] from MAME</ref>/''Galaxian''<ref>[https://github.com/mamedev/mame/blob/master/src/mame/video/galaxian.cpp video/galaxian.cpp] from MAME. The "6MHz" mentioned in some comments is only an approximation.</ref> hardware and derivatives such as ''Pengo'' (288px)<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/pengo.cpp pengo.cpp] from MAME</ref><br />Namco ''Super Pac-Man'' family,<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/mappy.cpp mappy.cpp] from MAME</ref> System 86,<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/namcos86.cpp namcos86.cpp] from MAME</ref> 1,<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/namcos1.cpp namcos1.cpp] from MAME</ref> 2,<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/namcos2.cpp namcos2.cpp] from MAME</ref> and ND-1<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/namcond1.cpp namcond1.cpp] from MAME</ref> (all 288px)
 +
|-
 +
| 6.25 MHz || 25/4 MHz || 0.981 || 54:55 || Sega X-Board (320px)<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/segaxbd.cpp segaxbd.cpp] from MAME</ref>
 
|-
 
|-
 
| 6.29 MHz || 900/143 MHz || 0.975 || 39:40 || Sega ''Hang-On''/''Space Harrier''<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/segahang.cpp MAME segahang.cpp]</ref>, ''OutRun''<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/segaorun.cpp MAME segaorun.cpp]</ref>, and System 16B hardware<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/segas16b.cpp MAME segas16b.cpp]. Look carefully at how <code>MASTER_CLOCK_25MHz</code> is defined. System 16A contains the same crystal according to comments in xtal.h, but its use is not yet noted in [https://github.com/mamedev/mame/blob/master/src/mame/drivers/segas16a.cpp segas16a.cpp].</ref> (all 320px) divide a VGA crystal by 4.<br />Mode X (320x240) on VGA has twice the dot rate and repeats each line twice, giving it the same PAR.
 
| 6.29 MHz || 900/143 MHz || 0.975 || 39:40 || Sega ''Hang-On''/''Space Harrier''<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/segahang.cpp MAME segahang.cpp]</ref>, ''OutRun''<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/segaorun.cpp MAME segaorun.cpp]</ref>, and System 16B hardware<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/segas16b.cpp MAME segas16b.cpp]. Look carefully at how <code>MASTER_CLOCK_25MHz</code> is defined. System 16A contains the same crystal according to comments in xtal.h, but its use is not yet noted in [https://github.com/mamedev/mame/blob/master/src/mame/drivers/segas16a.cpp segas16a.cpp].</ref> (all 320px) divide a VGA crystal by 4.<br />Mode X (320x240) on VGA has twice the dot rate and repeats each line twice, giving it the same PAR.
 
|-
 
|-
| 6.71 MHz || 4725/704 MHz || 0.91 || 32:35 || Sega Genesis and PlayStation 320px mode,<ref>[//forums.nesdev.com/viewtopic.php?p=95154#p95154 kyuusaku reasons from the 15*CB oscillator]</ref><ref name="ryphecha_ps1"/> very close to SIF
+
| 6.71 MHz || 4725/704 MHz || 0.914 || 32:35 || Sega Genesis and PlayStation 320px mode,<ref>[//forums.nesdev.com/viewtopic.php?p=95154#p95154 kyuusaku reasons from the 15*CB oscillator]</ref><ref name="ryphecha_ps1"/> very close to SIF
 
|-
 
|-
| 6.75 MHz || 27/4 MHz || 0.91 || 10:11 || MPEG-1 NTSC [[wikipedia:Source Input Format|SIF]] (352 or 360px): CD-i, Video CD. Equal to Rec. 601 chroma rate or half Rec. 601 luma rate.<br />Toaplan/Raizing 2nd-generation arcade boards (320px)<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/toaplan2.cpp toaplan2.cpp] from MAME</ref>
+
| 6.75 MHz || 27/4 MHz || 0.909 || 10:11 || MPEG-1 NTSC [[wikipedia:Source Input Format|SIF]] (352 or 360px): CD-i, Video CD. Equal to Rec. 601 chroma rate or half Rec. 601 luma rate.<br />Toaplan/Raizing 2nd-generation arcade boards (320px)<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/toaplan2.cpp toaplan2.cpp] from MAME</ref>
 
|-
 
|-
| 6.75 MHz || 27/4 MHz || 1.82 (i) || 20:11 (i) || Low-resolution [[wikipedia:DVD-Video|DVD-Video]], such as that produced by DVD recorders in long play mode
+
| 6.75 MHz || 27/4 MHz || 1.818 (i) || 20:11 (i) || Low-resolution [[wikipedia:DVD-Video|DVD-Video]], such as that produced by DVD recorders in long play mode
 
|-
 
|-
| 7.00 MHz || 7/1 MHz || 0.88 || 135:154 || Toaplan/Taito ''Wardner'' hardware,<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/wardner.cpp wardner.cpp] from MAME</ref> Toaplan "1st generation" hardware,<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/toaplan1.cpp toaplan1.cpp] from MAME</ref> Technos ''Double Dragon 3'' family (all 320px)<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/ddragon3.cpp ddragon3.cpp] from MAME</ref>
+
| 7.00 MHz || 7/1 MHz || 0.877 || 135:154 || Toaplan/Taito ''Wardner'' hardware,<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/wardner.cpp wardner.cpp] from MAME</ref> Toaplan "1st generation" hardware,<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/toaplan1.cpp toaplan1.cpp] from MAME</ref> Technos ''Double Dragon 3'' family (all 320px)<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/ddragon3.cpp ddragon3.cpp] from MAME</ref>
 
|-
 
|-
| 7.16 MHz || 315/44 MHz || 0.86 || 6:7 || Apple II (40-column text, HGR 280px); TG16 (mid-res, up to 352px); Atari 7800 (hi-res, 320px); Amiga, IBM CGA (40-column or 320px)<ref name="towcrystals">[[Wikipedia:Crystal oscillator frequencies]]</ref> and EGA in 200-line mode (40-column or 320px)<ref>reenigne. "[http://www.vintage-computer.com/vcforum/archive/index.php/t-41021.html VGA 15kHz Output]". 2014-01-18. Accessed 2016-01-26.</ref>; Atari 800<ref>[https://atariage.com/forums/topic/189995-confusion-with-aspect-ratios/#entry2403136 phaeron's post]</ref>; [[wikipedia:TRS-80 Color Computer|Tandy Color Computer]] (COCO) and other computers using [[wikipedia:Motorola 6847|Motorola 6847]] video chip<ref>The 6847 is clocked at the NTSC color burst frequency. [https://courses.cit.cornell.edu/ee476/ideas/mc6847.pdf Its datasheet] lists the left and right border widths as 29.5 and 28 cycles on p. 5, and subtracting those from the 186+2/3 cycles of a standard scanline leaves just over 131 cycles of active picture. In addition, tDOT on p. 7 appears to be half a color burst cycle. Furthermore, the width of low and high phases of the clock "controls the width of alternate dots on the television screen" (p. 13).</ref>; Atari ''Tetris'' and ''Klax'' arcade games (336px)<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/atetris.cpp atetris.cpp] and [https://github.com/mamedev/mame/blob/master/src/mame/drivers/klax.cpp klax.cpp] from MAME</ref>
+
| 7.16 MHz || 315/44 MHz || 0.857 || 6:7 || Apple II (40-column text, HGR 280px); TG16 (mid-res, up to 352px); Atari 7800 (hi-res, 320px); Amiga, IBM CGA (40-column or 320px)<ref name="towcrystals">[[Wikipedia:Crystal oscillator frequencies]]</ref> and EGA in 200-line mode (40-column or 320px)<ref>reenigne. "[http://www.vintage-computer.com/vcforum/archive/index.php/t-41021.html VGA 15kHz Output]". 2014-01-18. Accessed 2016-01-26.</ref>; Atari 800<ref>[https://atariage.com/forums/topic/189995-confusion-with-aspect-ratios/#entry2403136 phaeron's post]</ref>; [[wikipedia:TRS-80 Color Computer|Tandy Color Computer]] (COCO) and other computers using [[wikipedia:Motorola 6847|Motorola 6847]] video chip<ref>The 6847 is clocked at the NTSC color burst frequency. [https://courses.cit.cornell.edu/ee476/ideas/mc6847.pdf Its datasheet] lists the left and right border widths as 29.5 and 28 cycles on p. 5, and subtracting those from the 186+2/3 cycles of a standard scanline leaves just over 131 cycles of active picture. In addition, tDOT on p. 7 appears to be half a color burst cycle. Furthermore, the width of low and high phases of the clock "controls the width of alternate dots on the television screen" (p. 13).</ref>; Atari ''Tetris'' and ''Klax'' arcade games (336px)<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/atetris.cpp atetris.cpp] and [https://github.com/mamedev/mame/blob/master/src/mame/drivers/klax.cpp klax.cpp] from MAME</ref>
 
|-
 
|-
| 7.50 MHz || 15/2 MHz || 0.82 || 9:11 || Capcom CPS3 (384px)<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/cps3.cpp cps3.cpp] from MAME</ref>
+
| 7.67 MHz || 4725/616 MHz || 0.800 || 4:5 || PlayStation (366px)<ref name="ryphecha_ps1"/>
 
|-
 
|-
| 7.67 MHz || 4725/616 MHz || 0.8 || 4:5 || PlayStation (366px)<ref name="ryphecha_ps1"/>
+
| 8.00 MHz || 8/1 MHz || 0.767 || 135:176 || Williams 6809-based arcade system (276, 292, or 316px)<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/williams.cpp williams.cpp] from MAME</ref><br />Capcom CP System and CP System II (384px)<ref>[https://github.com/mamedev/mame/blob/master/src/mame/includes/cps1.h includes/cps1.h] from MAME. For comparison, Irem's M72 family ([https://github.com/mamedev/mame/blob/master/src/mame/drivers/m72.cpp m72.cpp]) and Konami's ''Xexex'' ([https://github.com/mamedev/mame/blob/master/src/mame/drivers/xexex.cpp xexex.cpp]) also use a 384px-wide clean aperture and an 8MHz dot clock, but they have slower-than-NTSC frame rates of about 54&ndash;55 Hz.</ref>
 
|-
 
|-
| 8.00 MHz || 8/1 MHz || 0.77 || 135:176 || Williams 6809-based arcade system (276, 292, or 316px)<ref>[https://github.com/mamedev/mame/blob/master/src/mame/drivers/williams.cpp williams.cpp] from MAME</ref><br />Capcom CPS1 and CPS2 (384px)<ref>[https://github.com/mamedev/mame/blob/master/src/mame/includes/cps1.h includes/cps1.h] from MAME. For comparison, Irem's M72 family ([https://github.com/mamedev/mame/blob/master/src/mame/drivers/m72.cpp m72.cpp]) and Konami's ''Xexex'' ([https://github.com/mamedev/mame/blob/master/src/mame/drivers/xexex.cpp xexex.cpp]) also use a 384px-wide clean aperture and an 8MHz dot clock, but they have slower-than-NTSC frame rates of about 54&ndash;55 Hz.</ref>
+
| 8.19 MHz || 630/77 MHz || 0.750 || 3:4 || Commodore 64 and Apple IIGS 4bpp super hi-res<ref name="mahon_iigs_shr">[https://groups.google.com/d/msg/comp.sys.apple2/NXO2V0UP1Hc/H17S7rQAI0QJ Post] by Michael J. Mahon to comp.sys.apple2</ref> (both 320px). Square on widescreen monitors.
 
|-
 
|-
| 8.19 MHz || 630/77 MHz || 0.75 || 3:4 || Commodore 64 and Apple IIGS 4bpp super hi-res<ref name="mahon_iigs_shr">[https://groups.google.com/d/msg/comp.sys.apple2/NXO2V0UP1Hc/H17S7rQAI0QJ Post] by Michael J. Mahon to comp.sys.apple2</ref> (both 320px). Square on widescreen monitors.
+
| 8.60 MHz || 189/22 MHz || 0.714 || 5:7 || Capcom CP System III (384px mode)<ref name="mame_cps3">[https://github.com/mamedev/mame/blob/master/src/mame/drivers/cps3.cpp cps3.cpp] from MAME</ref>
 
|-
 
|-
| 10.74 MHz || 945/88 MHz || 0.57 || 4:7 || Twice the TMS9918 pixel rate produces 512px on Super NES, TG16, and PlayStation<ref name="ryphecha_ps1"/>
+
| 10.74 MHz || 945/88 MHz || 0.571 || 4:7 || Twice the TMS9918 pixel rate produces 512px on Super NES, TG16, and PlayStation<ref name="ryphecha_ps1"/> and 496px on CP System III<ref name="mame_cps3" />
 
|-
 
|-
| 12.27 MHz || 135/11 MHz || 1.00 (i) || 1:1 (i) || Square interlaced pixels
+
| 12.27 MHz || 135/11 MHz || 1.000 (i) || 1:1 (i) || Square interlaced pixels
 
|-
 
|-
| 13.42 MHz || 4725/352 MHz || 0.46 || 16:35 || PlayStation (640px)<ref name="ryphecha_ps1"/>
+
| 13.42 MHz || 4725/352 MHz || 0.457 || 16:35 || PlayStation (640px)<ref name="ryphecha_ps1"/>
 
|-
 
|-
| 13.50 MHz || 27/2 MHz || 0.91 (i) || 10:11 (i) || Rec. 601 luma rate as used in [[wikipedia:D-1 (Sony)|D1 tape]] and DVD Video (704px)<br />
+
| 13.50 MHz || 27/2 MHz || 0.909 (i) || 10:11 (i) || Rec. 601 luma rate as used in [[wikipedia:D-1 (Sony)|D1 tape]] and DVD Video (704px)<br />
 
Nintendo GameCube (640px), based on (nominally?) 27 and 54 MHz clock signals in digital AV out<ref name="Reilink">Rob Reilink. "[http://comments.gmane.org/gmane.linux.ports.game-cube.devel/503 Video modes on Gamecube]". gc-linux-devel, 2006-03-03. Accessed 2016-04-02.</ref><ref name="nintendodigitalav">"[http://gamesx.com/wiki/doku.php?id=av:nintendodigitalav Nintendo GameCube Digital AV Connector]". ''NFG Games + GameSX''. Accessed 2016-04-02.</ref>
 
Nintendo GameCube (640px), based on (nominally?) 27 and 54 MHz clock signals in digital AV out<ref name="Reilink">Rob Reilink. "[http://comments.gmane.org/gmane.linux.ports.game-cube.devel/503 Video modes on Gamecube]". gc-linux-devel, 2006-03-03. Accessed 2016-04-02.</ref><ref name="nintendodigitalav">"[http://gamesx.com/wiki/doku.php?id=av:nintendodigitalav Nintendo GameCube Digital AV Connector]". ''NFG Games + GameSX''. Accessed 2016-04-02.</ref>
 
|-
 
|-
| 14.32 MHz || 315/22 MHz || 0.43 || 3:7 || Apple II (80-column text, double hi-res); Amiga; IBM CGA (80-column)<ref name="towcrystals" />
+
| 14.32 MHz || 315/22 MHz || 0.429 || 3:7 || Apple II (80-column text, double hi-res); Amiga; IBM CGA (80-column)<ref name="towcrystals" />
 
|-
 
|-
 
| 16.36 MHz || 1260/77 MHz || 0.375 || 3:8 || Apple IIGS 2bpp super hi-res (640px)<ref name="mahon_iigs_shr" /> though Apple has claimed 5:12 instead<ref>[http://www.umich.edu/~archive/apple2/technotes/tn/iigs/TN.IIGS.041 Apple IIGS Tech Note #41: Font Family Numbers]</ref>
 
| 16.36 MHz || 1260/77 MHz || 0.375 || 3:8 || Apple IIGS 2bpp super hi-res (640px)<ref name="mahon_iigs_shr" /> though Apple has claimed 5:12 instead<ref>[http://www.umich.edu/~archive/apple2/technotes/tn/iigs/TN.IIGS.041 Apple IIGS Tech Note #41: Font Family Numbers]</ref>
Line 71: Line 75:
 
| 25.17 MHz || 3600/143 MHz || 0.975 || 39:40 || VGA mode 12h (640x480). The horizontal scan rate is twice NTSC, and the dot clock is 800 times that: 640 dots of picture and 160 of blanking.<ref name="towvga">[[Wikipedia:Video Graphics Array]]. Accessed 2013-09-24.</ref>
 
| 25.17 MHz || 3600/143 MHz || 0.975 || 39:40 || VGA mode 12h (640x480). The horizontal scan rate is twice NTSC, and the dot clock is 800 times that: 640 dots of picture and 160 of blanking.<ref name="towvga">[[Wikipedia:Video Graphics Array]]. Accessed 2013-09-24.</ref>
 
|-
 
|-
| 27.00 MHz || 27/1 MHz || 0.91 || 10:11 || Twice Rec. 601 luma rate, as produced by progressive scan DVD players (704px)<br />
+
| 27.00 MHz || 27/1 MHz || 0.909 || 10:11 || Twice Rec. 601 luma rate, as produced by progressive scan DVD players (704px)<br />
 
Nintendo GameCube<ref name="Reilink" /><ref name="nintendodigitalav" /> and Wii progressive component video (640px)
 
Nintendo GameCube<ref name="Reilink" /><ref name="nintendodigitalav" /> and Wii progressive component video (640px)
 
|}
 
|}

Latest revision as of 03:22, 24 September 2019

The following frequencies are the dot clock rates of digital picture generators outputting 240p low-definition video signals that are compatible with NTSC monitors or otherwise at near-System M scan rates (15.7 kHz horizontal, 60 Hz vertical). The pixel aspect ratio that each rate produces, assuming the 480-line picture and 52.148 microsecond active scanline period of Rec. 601, is also given.

A few things may cause this ratio to differ in a particular environment:

  • Some coin-operated machines use a different active scanline period, and the arcade operator is expected to adjust the monitor's picture size to match a test pattern displayed in a particular game's service mode. An arcade-to-television adapter would produce the pixel aspect ratio listed below.
  • Some devices also support 480i (interlaced) video, where even scanlines are drawn in one field and odd scanlines are drawn in the other field. Interlaced video makes pixels half as tall as in 240p, doubling the pixel aspect ratio, and ratios assuming interlace are marked as such.
  • Sets of the 240p era were built for 4:3 display aspect ratio, as opposed to the 16:9 aspect ratio that became common between the late 1990s and mid-2000s; multiply the pixel aspect ratios by 4/3 if stretching the picture on a widescreen TV.
Frequency Exact frequency PAR Exact PAR Devices
1.02 MHz 315/308 MHz 1.500 3:2 Apple II (GR; each line repeated four times)
3.58 MHz 315/88 MHz 1.714 12:7 Devices with 1 pixel per NTSC subcarrier period: Atari 2600, Atari 7800, Intellivision
4.61 MHz 576/125 MHz 1.332 1875:1408 Konami GX400 family (a.k.a. Nemesis and Bubble System) (256px)[1]
5.00 MHz 5/1 MHz 1.227 27:22 Atari Missile Command[2] and Crystal Castles hardware[3], Stern Berzerk/Frenzy hardware[4] (all 256px)
5.37 MHz 945/176 MHz 1.143 8:7 The 256px display of the TMS9918 (TI-99/4A, ColecoVision, MSX, and SG-1000), its descendants (MSX2, Master System, Genesis, Game Gear[5]), and other VDPs inspired by it (NES, TurboGrafx-16,[6] Super NES), and 256px mode of the original PlayStation[7]
5.59 MHz 16777216/3 Hz 1.097 6328125:5767168 Nintendo DS (256px) is the ~33.5 MHz (apparently 225 Hz) master clock divided by 6[8]
6.00 MHz 6/1 MHz 1.023 45:44 Data East Lock'n Chase/BurgerTime family (240 or 256px)[9], DECO Cassette System (256px)[10], and BreakThru family (240px)[11]
Technos Double Dragon hardware,[12] SNK pre-Neo Geo 68000-based hardware,[13] Taito Arkanoid[14] and Bubble Bobble[15] hardware, Jaleco Mega System 1-A[16] (all 256px)
Konami GX[17] and pre-GX (Mystic Warriors) family[18] (288px)
Neo Geo MVS (320px)[19]
6.04 MHz 6048/1001 MHz 1.016 65:64 Neo Geo AES (320px)[20]
6.05 MHz 756/125 MHz 1.015 625:616 Namco NB-1/NB-2 family (288px)[21]
6.09 MHz 1071/176 MHz 1.008 120:119 Nintendo 64 (320px)[22][23][24]
6.14 MHz 135/22 MHz 1.000 1:1 Rec. 601 defines the NTSC picture such that this is square on 4:3 monitors
6.14 MHz 768/125 MHz 0.999 5625:5632 48000 kHz (DAT and DVD audio rate) * 128[25] approximates square pixels to within 1 part in 800
Irem M52 (Moon Patrol) (240px)[26]
Namco Pac-Man[27]/Galaxian[28] hardware and derivatives such as Pengo (288px)[29]
Namco Super Pac-Man family,[30] System 86,[31] 1,[32] 2,[33] and ND-1[34] (all 288px)
6.25 MHz 25/4 MHz 0.981 54:55 Sega X-Board (320px)[35]
6.29 MHz 900/143 MHz 0.975 39:40 Sega Hang-On/Space Harrier[36], OutRun[37], and System 16B hardware[38] (all 320px) divide a VGA crystal by 4.
Mode X (320x240) on VGA has twice the dot rate and repeats each line twice, giving it the same PAR.
6.71 MHz 4725/704 MHz 0.914 32:35 Sega Genesis and PlayStation 320px mode,[39][7] very close to SIF
6.75 MHz 27/4 MHz 0.909 10:11 MPEG-1 NTSC SIF (352 or 360px): CD-i, Video CD. Equal to Rec. 601 chroma rate or half Rec. 601 luma rate.
Toaplan/Raizing 2nd-generation arcade boards (320px)[40]
6.75 MHz 27/4 MHz 1.818 (i) 20:11 (i) Low-resolution DVD-Video, such as that produced by DVD recorders in long play mode
7.00 MHz 7/1 MHz 0.877 135:154 Toaplan/Taito Wardner hardware,[41] Toaplan "1st generation" hardware,[42] Technos Double Dragon 3 family (all 320px)[43]
7.16 MHz 315/44 MHz 0.857 6:7 Apple II (40-column text, HGR 280px); TG16 (mid-res, up to 352px); Atari 7800 (hi-res, 320px); Amiga, IBM CGA (40-column or 320px)[25] and EGA in 200-line mode (40-column or 320px)[44]; Atari 800[45]; Tandy Color Computer (COCO) and other computers using Motorola 6847 video chip[46]; Atari Tetris and Klax arcade games (336px)[47]
7.67 MHz 4725/616 MHz 0.800 4:5 PlayStation (366px)[7]
8.00 MHz 8/1 MHz 0.767 135:176 Williams 6809-based arcade system (276, 292, or 316px)[48]
Capcom CP System and CP System II (384px)[49]
8.19 MHz 630/77 MHz 0.750 3:4 Commodore 64 and Apple IIGS 4bpp super hi-res[50] (both 320px). Square on widescreen monitors.
8.60 MHz 189/22 MHz 0.714 5:7 Capcom CP System III (384px mode)[51]
10.74 MHz 945/88 MHz 0.571 4:7 Twice the TMS9918 pixel rate produces 512px on Super NES, TG16, and PlayStation[7] and 496px on CP System III[51]
12.27 MHz 135/11 MHz 1.000 (i) 1:1 (i) Square interlaced pixels
13.42 MHz 4725/352 MHz 0.457 16:35 PlayStation (640px)[7]
13.50 MHz 27/2 MHz 0.909 (i) 10:11 (i) Rec. 601 luma rate as used in D1 tape and DVD Video (704px)

Nintendo GameCube (640px), based on (nominally?) 27 and 54 MHz clock signals in digital AV out[52][53]

14.32 MHz 315/22 MHz 0.429 3:7 Apple II (80-column text, double hi-res); Amiga; IBM CGA (80-column)[25]
16.36 MHz 1260/77 MHz 0.375 3:8 Apple IIGS 2bpp super hi-res (640px)[50] though Apple has claimed 5:12 instead[54]

For comparison, here are some enhanced-definition (480p) rates, with a horizontal scan frequency close to 31.5 kHz:

Frequency Exact frequency PAR Exact PAR Devices
25.17 MHz 3600/143 MHz 0.975 39:40 VGA mode 12h (640x480). The horizontal scan rate is twice NTSC, and the dot clock is 800 times that: 640 dots of picture and 160 of blanking.[55]
27.00 MHz 27/1 MHz 0.909 10:11 Twice Rec. 601 luma rate, as produced by progressive scan DVD players (704px)

Nintendo GameCube[52][53] and Wii progressive component video (640px)

References

  1. nemesis.cpp from MAME; this information had been included in the MAME driver code as an arithmetic calculation long before the modern set_raw function was called
  2. missile.cpp from MAME
  3. ccastles.cpp from MAME
  4. berzerk.cpp from MAME
  5. Game Gear divides a 32.2159 MHz crystal by 6 to produce the dot clock. This frequency is 9 times NTSC color burst, and each RGB pixel is 6 dots, divided into three 2-dot subpixels. Evil Tim's SCART mod produces 240p RGB output centered in the screen with the same size as a Super Game Boy picture.
  6. HuC6260 - Archaic Pixels
  7. 7.0 7.1 7.2 7.3 7.4 The PS1 divides a 15 times NTSC (53.69 MHz) crystal by 10, 8, 7, 5, or 4 Post by Ryphecha on Mednafen forum
  8. GBATEK by Martin Korth
  9. btime.cpp from MAME
  10. decocass.cpp from MAME
  11. brkthru.cpp from MAME
  12. ddragon.cpp from MAME
  13. snk68.cpp from MAME
  14. arkanoid.cpp from MAME
  15. bublbobl.cpp from MAME
  16. megasys1.cpp from MAME. The same pixel clock is possible but unverified for the other Mega System 1 variants.
  17. konamigx.cpp from MAME
  18. mystwarr.cpp from MAME
  19. video/neogeo_spr.h from MAME. Many Neo Geo games are designed around a safe area approximately 304 pixels wide.
  20. 384 pixels per standard 227.5-cycle scanline period. See NESdev posts by TmEE and psycopathicteen. TODO: Verify whether the timing differences from MVS are noted anywhere in the MAME source code.
  21. namconb1.cpp from MAME: same divisor and dot counts that originated from Galaxian, except with a slower crystal (48.384MHz)
  22. assemblergames forum post
  23. MX8350 clock generator
  24. includes/n64.h from MAME. Note the mention of quarter-pixel scanline length in n64.cpp; divide the given DACRATE_NTSC by 8 to obtain the result here.
  25. 25.0 25.1 25.2 Wikipedia:Crystal oscillator frequencies
  26. m52.cpp from MAME
  27. pacman.cpp from MAME
  28. video/galaxian.cpp from MAME. The "6MHz" mentioned in some comments is only an approximation.
  29. pengo.cpp from MAME
  30. mappy.cpp from MAME
  31. namcos86.cpp from MAME
  32. namcos1.cpp from MAME
  33. namcos2.cpp from MAME
  34. namcond1.cpp from MAME
  35. segaxbd.cpp from MAME
  36. MAME segahang.cpp
  37. MAME segaorun.cpp
  38. MAME segas16b.cpp. Look carefully at how MASTER_CLOCK_25MHz is defined. System 16A contains the same crystal according to comments in xtal.h, but its use is not yet noted in segas16a.cpp.
  39. kyuusaku reasons from the 15*CB oscillator
  40. toaplan2.cpp from MAME
  41. wardner.cpp from MAME
  42. toaplan1.cpp from MAME
  43. ddragon3.cpp from MAME
  44. reenigne. "VGA 15kHz Output". 2014-01-18. Accessed 2016-01-26.
  45. phaeron's post
  46. The 6847 is clocked at the NTSC color burst frequency. Its datasheet lists the left and right border widths as 29.5 and 28 cycles on p. 5, and subtracting those from the 186+2/3 cycles of a standard scanline leaves just over 131 cycles of active picture. In addition, tDOT on p. 7 appears to be half a color burst cycle. Furthermore, the width of low and high phases of the clock "controls the width of alternate dots on the television screen" (p. 13).
  47. atetris.cpp and klax.cpp from MAME
  48. williams.cpp from MAME
  49. includes/cps1.h from MAME. For comparison, Irem's M72 family (m72.cpp) and Konami's Xexex (xexex.cpp) also use a 384px-wide clean aperture and an 8MHz dot clock, but they have slower-than-NTSC frame rates of about 54–55 Hz.
  50. 50.0 50.1 Post by Michael J. Mahon to comp.sys.apple2
  51. 51.0 51.1 cps3.cpp from MAME
  52. 53.0 53.1 "Nintendo GameCube Digital AV Connector". NFG Games + GameSX. Accessed 2016-04-02.
  53. Apple IIGS Tech Note #41: Font Family Numbers
  54. Wikipedia:Video Graphics Array. Accessed 2013-09-24.