Mega Man 2/RAM map

The following article is a RAM map for Mega Man 2.

General

RAM	Function	Details
$001B	Camera state	$00 Default $01 Changing the nametable (E.g. scrolling within an area, creating the pause menu) $02 Freeze before and after scrolling to a new area $80 Scrolling vertically
$001F	Camera X position
$0020	Camera X screen	When $001F gets larger than $FF, this value increases by $01.
$0022	Camera Y position
$0023	Controller 1 Poll	(1)
$0025	Controller 1 Mirror	(1)
$0027	Controller 1 Poll	Only changes on first frame of state change. Crash Man checks this for jump code. (1)
$0030	Gravity
$004B	Invincibility timer	When above $00, invincibility frames will start and this will count down at a rate of $01 per frame.
$00CB	Difficulty setting	When an enemy takes damage, if this value is $00 (Normal) the damage given will be bitshifted left, doubling it.
$002A	Stage select cursor position	$00 is Dr. Wily, $01-$08 goes clockwise starting from Bubble Man.
$06C1	Boss HP

Sound

RAM	Function	Details
$0066	Sound effects strobe	Write $01 to play the SFX ID in address $0580
$0067	Music strobe	Write $01 to play the Music in address $0000
$0580	Sound effect queue

Player properties

RAM	Function	Details
$06C0	Mega Man's HP
$0460	Mega Man's X location
$04A0	Mega Man's Y location
$0036	Shooting pose timer
$0032	Tile type Mega Man is standing on (feet)	Value Type $00 Air $01 Ground $02 Ladder $03 Instadeath (Spikes, Lava) $04 Water $05 Right Conveyer $06 Left Conveyer $07 Ice
$0033	Tile type Mega Man is standing on (center)
$0034	Tile type Mega Man is overlapping
$003D	Is Mega Man shooting?
$009A	Unlocked Weapons/Stages beaten	Bits Hex Weapon 0000 0001 $01 Atomic Fire 0000 0010 $02 Air Shooter 0000 0100 $04 Leaf Shield 0000 1000 $08 Bubble Lead 0001 0000 $10 Quick Boomerang 0010 0000 $20 Time Stopper 0100 0000 $40 Metal Blade 1000 0000 $80 Crash Bomb
$009B	Unlocked Items	Bits Hex Item 0000 0001 $01 Item 1 (Helicopter Platform) 0000 0010 $02 Item 2 (Jet Sled) 0000 0100 $04 Item 3 (Climbing Platform)
$009C	Atomic Fire Ammo
$009D	Air Shooter Ammo
$009E	Leaf Shield Ammo
$009F	Bubble Lead Ammo
$00A0	Quick Boomerang Ammo
$00A1	Time Stopper Ammo
$00A2	Metal Blade Ammo
$00A3	Crash Bomb Ammo
$00A4	Item 1 Ammo
$00A5	Item 2 Ammo
$00A6	Item 3 Ammo
$00A7	Number of Energy Tanks Remaining	Can go above $04, but will break passwords.
$00A8	Number of Lives remaining	Looks glichy on the pause menu if greater than $64.
$0367-0369	Mega Man's Color Palette

RAM	Size (in bytes)	Description
$0F12	1	Mega Man facing: $00: left, $01: right
$0F15	1	Mega Man X coordinate
$0F16	1	Mega Man Y coordinate
$0F39	1	Frame counter for main gameplay (pauses during pause menu)

Graphics

RAM	Function	Details
$0200-$2FF	Sprite memory	These values are constantly read and sent to OAM. (2)
$0354	Palette cycling pattern	Values seem level-dependent?
$0355	Palette cycling speed	How many frames to wait before cycling the palette, $00 for no cycling. May glitch outside of levels.
$0356-$365	Palette memory (background)
$0366-$375	Palette memory (sprites)

Password Screen

RAM	Function	Details
$0420 - $0438	If 01, this grid space contains a dot.	Goes from left to right, top to bottom.
$0680	Number of dots left on Password entering
$0680	Position of cursor on Password entering

References

1. NESDev controller bits reference
2. NESDev sprite format reference