Sonic the Hedgehog (Sega Master System, Game Gear)/RAM map

The following article is a RAM map for Sonic the Hedgehog (Sega Master System, Game Gear).

These addresses are for the Sega Master System version.

Note that sizes are listed in decimal.

Offset	Size		Description
----	----		-----------
C000	4096		Level layout
D000	26		Sonic credits movement data
D063	1		Sprite 1 X value on camera
D064	1		Sprite 1 Y value on camera
D075	1		Sprite 2 X value on camera
D076	1		Sprite 2 Y value on camera
D100	440		Camera data?
D1B8	72		Empty
D203	1		Controller input (FF none, XE up, XD Down, XB Left, X7 Right, CX Button 1, DX Button 2)
D205	1		Level type|Normal/Demo switch
D207	1		Timer/Pause flag?
D20A	1		Monitor flash flag
D20E	1		Lettering flag?
D212	1		Related to Sonic screech
D212	3		Time bonus
D214	2		Sonic's position hitbox X
D216	1		Time bonus hex number & Continue countdown
D219	1		Title Screen trigger?
D223	2		Total Frame tally in levels
D225	6		Empty?
D22B	1		autopalette cycles 1
D230	1		autopalette cycles 2
D235	1		Tilemap bank value
D23C	1		Sprite table byte
D23E	1		Current act
D23F	1		Current Bonus act
D246	1		Lives value
D251	1		Freeroll Camera X
D252	1		Freeroll Camera Y
D257	1		Camera place X
D258	1		Camera place Y
D25A	2		Camera X values
D25D	2		Camera Y values
D26B	2		End post X camera position
D26D	2		End post Y camera position
D271	2		Camera Y values 2
D273	1		Camera positioning
D275	1		End Post camera centering
D27F	1		Emeralds collected counter
D280	1		Extra Lives gained by monitors counter (except special stages)
D281	1		Special Stages entered
D282	1		Special Stages complete 1
D283	1		Death flag for bonus
D284	1		Continue counter
D285	1		Special Stages complete 2
D287	1		Death timer before fadeout
D288	1		After landing post flag
D289	1		Timer after hitting post/machine to fading out level
D28A	1		Teleport timer
D28B	1		Time after picking up C.Emerald to restart music
D28C	1		Labyrinth Sonic sliding down water
D28D	1		Invincibility timer
D28E	1		Sonic's jump height when button is held
D297	1		Rings frames
D298	1		Ring spinning mechanism
D299	2		How long Sonic stands still for
D29B	2		Sonic underwater timer (LZ)
D2A5	1		Color Cycle speed
D2A6	1		Color cycles auto
D2A7	1		Color cycle of levels
D2A8	1		Lightning mechanism/auto palette
D2AA	1		Rings
D2AB	1		Growing flower flag
D2AD	1		Growing flower flag 2
D2AF	1		Growing flower sprite flag?
D2B4	1		Monitor flash flag 2
D2B7	2		Camera position
D2B9	1		Sonic's status sprite
D2BA	4		Score
D2AC	1		Pause switch
D2CE	3		Timer
D2D0	1		Timer milliseconds
D2D2	1		Previous Music byte
D2D4	1		Collision byte?
D2D9	2		Sonic's Y position (blocks)
D2DF	1		Sonic's sprite value?
D2E1	1		Star Bumper solidity timer
D2E4	1		Star Bumper sonic position
D2E9	1		Sky Base Lightning timer (AB)
D2EC	1		Boss hit tally
D2FB	1		Sonic bubble pickup frames
D2FC	1		Song that plays after C.Emerald jingle
D2FD	1		Extra life every 50,000 points flag
D2FF	3		Special Bonus score
D302	1		Related to losing rings/Death
D305	1		Related to 1-up monitors
D30B	1		Related to Chaos Emeralds
D311	1		Related to checkpoint monitor
D317	1		Related to switches
D31D	1		Ring pickup frames
D31F	1		Related to rings
D321	1		Ring pickup frames
D354	1		Solidity byte
D355	1		Floor Width bytes
D357	1		Floor Height bytes
D359	1		Level left bytes
D35B	1		Level right bytes
D35D	1		Level top bytes
D35F	1		Level bottom bytes
D361	1		Sonic X start byte
D362	1		Sonic Y start byte
D363	1		Floor layout bytes
D365	1		Floor size bytes
D367	1		Floor mapping bytes
D369	1		Level art bytes
D36B	1		Sprite art bytes
D36D	1		Art bank byte
D36E	1		Initial palette byte
D36F	1		Cycle speed byte
D370	1		Cycle Count byte
D371	1		Cycle palette byte
D372	1		Object layout bytes
D374	1		Ring/Scroll flag
D375	1		Underwater Flag
D376	1		Time/Lightning Flag
D377	1		Unknown Flag
D378	1		Music Flag
D37E	62		Sprite block data
D3BC	32		Palette fade in/out block
D3FD	3		Sonic's X position (free)
D400	3		Sonic's Y position (free)
D404	1		Related to Sonic's speed
D410	1		Sonic's sprite flag
D411	1		Speed shoes timer
D41B	1		Labyrinth water height
D73B	1221		Empty
DC0A	3		Tempo of music
DC1C	unknown		Music data | DC2C Channel 1 music, DC59 Channel 2 music, DC86 Channel 3 music
DC2C	2		Channel 1 music
DC59	2		Channel 2 music
DC86	2		Channel 3 music
DD12	679		Empty