Castlevania (NES)/RAM map

The following article is a RAM map for Castlevania (NES).

Address    Size    Description
--------   ----    -----------
$0012        02    Various
                     CHR Data Pointer
                       Points to CHR data, stored as follows:
                       byte 0 = value for $0027; byte 1-2 = CHR data RAM address;
                       byte 3-4 = PPU write address; byte 5-6 = data size
$0018              System State
                       00 = Booting; 01 = Title Screen; 02 = Demo Mode; 03 = Start Game;
                       04 = Introduction; 05 = Gameplay; 06 = Respawning; 07 = Game Over;
                       08 = Door Transition; 09 = Autowalk; 0a = Entering Castle; 0b = Autoclimb;
                       0c = Scoring & Map; 0d = Continue; 0e = Falling; 0f = Ending
$0019              System Substate
$001A              Frame Counter (resets to 01 when changing rooms)
$001B              Graphics Enabled
$001D              Transition Timer (used for autowalk sequences, death animation, and loading rooms)
$001E              Title Screen Bat State
$001F              Fade-in Timer 
$0020              Tile Data Pointer
$0022              User Paused
$0024              Current ROM Bank
$0027              Previous ROM Bank
$0028              Stage
$0029              Previous Stage
$002A              Lives (01 = last life, can be set to #ff but displays as 99 max)
$002B              Difficulty
$002C              Score Target (grants 1Up when equal to $07FE, then increments by 3)
$002D              View Position Subpixel
$002E        02    View Position
$0035              Rightmost Tile Section
$0036              Leftmost Tile Section
$0037        02    Tile Map 1 Address
$0039        02    Tile Map 2 Address
$003B              Tile Refresh Cutoff (toggles #20 every 32 pixels view moves)
$003C              Scroll State
                       bit 0 = scroll right; bit 1 = scroll left; bit 2 = at room edge
$003D              Scroll Speed Subpixel
$003E              Off Stairs (always 00 at start of frame)
$003F              Simon Real Y-Coordinate
$0040        02    Simon X-Coordinate Copy (for solid collisions)
$0042        02    Timer
$0044              Simon Display Health (adjusts every 4 frames to match $0045)
$0045              Simon Real Health
$0046              Floor (for stages with stair transitions)
$0047              Stun Timer (when hit by enemies)
$0048              Boss Screen (locks scrolling)
$0049              Rightward Scroll Speed
$004A              Music Continuity (00 = load new BGM after stair & gate transitions)
$004B              Various
                     Y-coordinate offset for solid collision
                     Whip Collision Object
                     Sprite Mirrored copy for rendering
                     Subweapon ID ($015B - #08)
                     Display Health copy for adjusting health bars gradually
                     Crusher Y-Offset
$004C              Various
                     X-coordinate offset for solid collision
                     Sprite Data Low Byte
                     Enemy Drops Low Byte (indexed by [Stage-1]/3)
                     Collision Width (max horizontal distance in collision check)
                     Tile Solidity
                       40 = #5F<Tile ID<#6C; 80 = Tile ID is #66
$004D              Various
                     Sprite Data High Byte
                     Enemy Drops High Byte
                     Collision Height (max vertical distance in collision check)
$004E              Various
                     Tile Position Iterator (when loading new tiles)
                     Current Instance ID
                     Current Crusher ID
$004F              Various
                     Potential Spawner Pointer
                     Off-screen Attribute Overflow
                     Crusher Sequence ($001A - $004E)
$0051              Scroll Attribute Mask (ref. $0300)
                       00 = scrolled right; ff = scrolled left
$0052              Scroll Speed
$0053              Scroll Speed subpixel
$005B              Wounded Timer (for iFrames)
$005F              Simon Height
$0063              Ghoul Counter (spaces Ghouls apart in Stages 01 & 20)
$0064              Weapon Multiplier
$006D              Spawn Area To Load ($0075-5 or $0076+5)
$006F              Randomizer
$0070              Whip Level
$0071              Hearts
$0072              Subweapon Dropped (prevents multiple subweapons dropping)
$0073              Whip Length
$0074              Whip Height
$0075              Leftward Stage Spawn Zone
$0076              Rightward Stage Spawn Zone
$0079              Subweapon Kills (until Multiplier drop)
$007B              Enemy Drops ($007B & 3 determines item, ref. $004C)
$007D              Invincibility Potion Timer (unused, game uses $005B instead)
$007F              Ignore Sound Effect Request
$0080              Square Wave 1 Duration
$0081              Square Wave 1 Octave
$0082              Square Wave 1 Track
$0083        02    Square Wave 1 Note Address
$0085              Square Wave 1 Volume Envelope
$0087              Square Wave 1 Volume Write
$0088              Square Wave 1 Halt
$0089              Square Wave 1 Next Duration
$008A              Square Wave 1 Timbre
$008B              Square Wave 1 Fade Delay
$008C              Square Wave 1 Fade
$008D              Square Wave 1 Fade Speed
$008E        02    Square Wave 1 Loop Address
$0090              Square Wave 2 Duration
$0091              Square Wave 2 Octave
$0092              Square Wave 2 Track
$0093        02    Square Wave 2 Note Address
$0095              Square Wave 2 Volume Envelope
$0097              Square Wave 2 Volume Write
$0098              Square Wave 2 Halt
$0099              Square Wave 2 Next Duration
$009A              Square Wave 2 Timbre
$009B              Square Wave 2 Fade Delay
$009C              Square Wave 2 Fade
$009D              Square Wave 2 Fade Speed
$009E        02    Square Wave 2 Loop Address
$00A0              Triangle Wave Duration
$00A1              Triangle Wave Octave
$00A2              Triangle Wave Track
$00A3        02    Triangle Wave Note Address
$00A5              Triangle Wave Linear Counter
$00A7              Audio Timer Low copy 1
$00A9              Triangle Wave Next Duration
$00AB              Audio Channel Index
                       80 = Square 1; 90 = Square 2; A0 = Triangle
                       B0 = Noise; C0 = Square 1 SFX; D0 = Square 2 SFX
$00AC              Audio Channel Offset
$00AE        02    Triangle Wave Loop Address
$00B0              Noise Duration
$00B1              Noise Octave?
$00B2              Noise Track
$00B3        02    Noise Note Address
$00B7              Noise Volume
$00B8              Audio Timer Low copy 2
$00BA        02    Working Note Address (used by all channels)
$00BC              Audio Timer Hi
$00BD              Audio Timer Low
$00BE        02    Updated Note Address (same as $0083, $0093, $00A3, and $00B3)
$00C0              Square Wave 1 SFX Duration
$00C1              Square Wave 1 SFX Octave
$00C2              Square Wave 1 SFX Track
$00C3        02    Square Wave 1 SFX Note Address
$00C5              Square Wave 1 SFX Volume Envelope
$00C7              Square Wave 1 SFX Volume Write
$00C8              Square Wave 1 SFX Halt
$00C9              Square Wave 1 SFX Next Duration
$00CA              Square Wave 1 SFX Timbre
$00CB              Square Wave 1 SFX Fade Delay
$00CC              Square Wave 1 SFX Fade
$00CD              Square Wave 1 SFX Fade Speed
$00CE        02    Square Wave 1 SFX Loop Address
$00D0              Square Wave 2 SFX Duration
$00D1              Square Wave 2 SFX Octave
$00D2              Square Wave 2 SFX Track
$00D3        02    Square Wave 2 SFX Note Address
$00D5              Square Wave 2 SFX Volume Envelope
$00D7              Square Wave 2 SFX Volume Write
$00D8              Square Wave 2 SFX Halt
$00D9              Square Wave 2 SFX Next Duration
$00DA              Square Wave 2 SFX Timbre
$00DB              Square Wave 2 SFX Fade Delay
$00DC              Square Wave 2 SFX Fade
$00DD              Square Wave 2 SFX Fade Speed
$00DE        02    Square Wave 2 SFX Loop Address
$00E0        02    Audio Track Address
$00E2              Audio Fade-Out
$00E3              Audio Fade-Out Timer
$00E4              Audio Track Offset
$00E5              Audio Track
$00E6              Channel Pointer Alternate
$00E7              Channel Pointer
$00EE              Stopwatch Mute
$00EF              Pause Music
$00F1        02    Demo Behavior Address
$00F3              Demo Cycle (determines stage and behavior)
$00F4              Demo Mode
$00F5              Gamepad 1 Input Pressed
$00F6              Gamepad 2 Input Pressed
$00F7              Gamepad 1 Input Held
$00F8              Gamepad 2 Input Held
$00FC        02    PPU Scroll
$00FE              PPU Mask (to change colors or disable sprites)
$00FF              PPU Control
$0143              Fall Distance (stuns if greater than 7 when landing)
$0144              Secrets Found (per stage)
$0145              Secret Timer (how long Simon stands still)
$0146              Blocks Broken
$014A        03    Crusher State
                       bit 0 = active; bit 2 = pause all crushers; bit 3 = falling
$014D        03    Crusher Y-Coordinate (top of chain)
$0150        03    Crusher X-Coordinate Low
$0153        03    Crusher X-Coordinate High
$0156        03    Crusher Position
                       bits 0-3 = vertical-offset, multiplied by 8;
                       bits 4-7 = return position ($0156 >> 4 = $004B)
$015B              Subweapon
                       08 = Dagger; 09 = Boomerang; 0A = Rosary (cut);
                       0B = Holy Water; 0D = Axe; 0F = Stopwatch
$015C              Subweapons Locked
$015D              Rosary Flash
      Spawners indexed by position in room, modulo 06
$0160        06    Spawner Disabled
$0166        06    Spawner Object
$016C        06    Spawner State
$0172        06    Spawner X-Coordinate
$017E        06    Spawner Y-Coordinate
$0184        06    Spawner Timer
$0190        0f    Candle Status
                       0f = upper floor destroyed; f0 = lower floor destroyed
$01A9              Boss Real Health
$01AA              Boss Display Health
$0200        ff    OAM Data
      Instances typically ordered as follows:
        Gameplay:
          00 = Simon; 01-02 = Whip; 03-0d = Enemies; 0e-13 = Candles;
          14-16 = Subweapons; 17 = Hidden Treasure; 17-18 = Moving Platforms;
          18-1b = Debris (deliberately handled even while game is paused)
        Title Screen:
          00 = Bat; 01 = "C" Top; 02 = "C" Bottom
        Gate Screen:
          00 = Simon; 01 = Cloud; 02 = Left Bat; 03 = Right Bat
        Map Screen: 
          00 = Simon; 17 = Map Position; 18 = Target Position;
$0300        1c    Attributes
                       bit 0 = In-view; bit 7 = Invisible
$031C        1c    Sprite Frame
$0338        1c    Pallet Offset
$0354        1c    Y-Coordinate
$0370        1c    Y-Coordinate Subpixel
$038C        1c    X-Coordinate
$03A8        1c    X-Coordinate Subpixel
$03C4        1c    Vertical Speed 
$03E0        1c    Vertical Speed Subpixel
$03FC        1c    Horizontal Speed
$0418        1c    Horizontal Speed Subpixel
$0434        1c    Object Index
                     Simon's Objects (just another state machine):
                       00 = Passive; 01 = Standing Whip (and on stairs); 02 = Ducking Whip;
                       03 = Jumping Whip; 81 = Standing Subweapon; 83 = Jumping Subweapon
$0450        1c    Sprite Mirrored
$046C        1c    State
                     Simon's States:
                       00 = Walking; 01 = Jumping (and Air Attack); 02 = Ground Attack;
                       03 = Ducking; 04 = Climbing Stairs; 05 = Knocked Back;
                       06 = Approach Stairs; 07 = Dropping; 08 = Dead; 09 = Stunned;
$0488              Jump State
$0489        1b    Animation Time 
$049F              Moving Platform Speed (doubles per speed)
$04A4              Simon Step Count (determines walking sprite frame)
$04A5        1b    Animation Frame
$04C0        1c    Sprite Index
  $04C2              Gate Bats Animation Timer (changes image every 4 frames)
  $04C3              Gate Right Bat Bob Timing
$04DC              Vertical Vector Address Low Byte
$04DF        0b    Various
                     Bat & Medusae Base Focal Y-coordinate
                     Simon above enemy
                     Skeleton Motion Substate
                     Fishman walking
                     Bone Dragon Part Motion Substate
                     Axe Armor Axe ID
  $04DF              Gate Right Bat Bob Offset (add to $0533)
$04EA        06    Candle Index (for $0190,Y writes)
$04F0        03    Subweapon Collision ID
$04F8              Vertical Vector Address High Byte
$04FB        11    Various
                     Movement Direction for moving backward
                       00 = right; 01 = left;
                     Bone Dragon Part Vertical Offset
                     Drop Pickup Delay (pointless)
$050C        03    Individual Subweapon Kills
$050F        04    Moving Platform X-Coordinate Subpixel
$0514              Vertical Direction
$0517        11    Various
                     Small Heart Focal X-coordinate
                     Bone Dragon Part Vertical Offset Subpixel
$052B              Moving Platform Left Edge
$0530              Simon Attack State (same as $046C)
$0531        15    Spawner ID (based on 6 room positions)
  $0533              Gate Right Bat Y-Origin
$054C              In-Air Attack
$054F        0d    Generic Timer
$0568              Whip Timer (counts up to #16)
$056B        11    Extinguish Timer (duration of flare and drop)
                     For subweapons:
                       Boomerang = return time; Holy Water = burn duration
$057F        02    Moving Platform Y-coordinate Subpixel
$0582              Hidden Treasure Object
                       00 = Coins; 01 = 1UP; 02 = Crown; 03 = Chest; 04 = Moai
$0584              Gamepad 1 Input Held Copy
$0587        11    Item Drop
$059B        02    Moving Platform Y-Coordinate
$05A0       160    Collision Map
$0700        c0    Tile Data Dump
$07F5              Previous Y Register (when audio loaded)
$07F6              Next Sound Effect
$07F8              Demo Gamepad Input Delay
$07F9              Demo Gamepad Input Pressed
$07FA              Demo Gamepad Input Held
$07FC        03    Score ($07FE used for 1UP checks)