The Legend of Zelda: Oracle of Seasons/RAM map

NOTE: All values in Tables are Hexadecimal unless noted otherwise.

The following article is a RAM map for The Legend of Zelda: Oracle of Seasons.

Bank 0 ($C000 - $CFFF)

TBD

RAM	Length	Purpose	Note
$C5C0 - $C5FF	64 Bytes	Unappraised Rings Carried
$C602 - $C607	6 Bytes	Player Name	Bytes $C602 $C603 $C604 $C605 $C606 $C607 First Letter Second Letter Third Letter Fourth Letter Fifth Letter Null Terminator This is always expected to be 0x00 Anything other than 0x00 will cause the game to softlock with either garbled graphics, or on a screen stating "This game can be played only on Game Boy® Color" Todo: Map valid characters.
$C616 - $C61D	8 Bytes	Rings Owned

Totals Since File Creation

RAM	Length	Purpose	Note
$C61E - $C61F	2 Bytes	Deaths	Value is represented in decimal This value will display on the file select screen.
$C620 - $C621	2 Bytes	Enemies Killed	When total killed enemies reaches 0x03E8, 0x01 is added to $C6CA to set a flag for Vasu to give the Slayer's Ring, and this no longer increments when killing enemies.
$C622 - $C625	4 Bytes	Time Passed (in frames)
$C626	1 Byte	Signs Destroyed
$C627 - $C628	2 Bytes	Rupees Collected	Value is represented in decimal. Example: If the total earned rupee count is 8,473, the hexadecimal representation will be 0x8473. When a rupee gain pushes the value over 0x9999, the value is then set to 0x6363, the value will no longer change, and $C6CA is then incremented by 0x02 so that Vasu will give the Rupee Ring the next time he is spoken with.

TBD

RAM	Length	Purpose	Note
$C629	1 Byte	Message Speed	0x00 - 0x04 Some higher values yield hilarious results such as a letter appearing once per few seconds.
$C63A	1 Byte	Current Level Bank
$C63B	1 Byte	Current Absolute Overworld Screen OR Current Relative Dungeon Screen	On the overworld, all 256 map tiles are represented in order; left to right, top to bottom, 0x00 - 0xFF. Inside a dungeon, only map tiles that are valid rooms are represented while empty map tiles are not counted; the only empty map tiles that are counted are the ones leading up to the first valid room in order, then from there, the value only increases with each valid room.
$C63C	1 Byte	Current Absolute Dungeon Screen	Unlike with $C63B, all tiles on the dungeon map, including ones that do not represent a valid room, are counted in order; left to right, top to bottom, 0x00 - 0xFF.
$C63D	1 Byte	Current Dungeon Floor

Enemies killed since...

RAM	Length	Purpose	Note
$C63E	1 Byte	Last Maple Encounter	Maple appears at the first available opportunity when this reaches 0x1E, then it resets to 0x00.
$C64C	1 Byte	Gasha Seed Planted at ??
$C64D	1 Byte	Gasha Seed Planted at ??
$C64E	1 Byte	Gasha Seed Planted at ??
$C64F	1 Byte	Gasha Seed Planted at ??
$C650	1 Byte	Gasha Seed Planted at ??
$C651	1 Byte	Gasha Seed Planted at ??
$C652	1 Byte	Gasha Seed Planted at ??
$C653	1 Byte	Gasha Seed Planted at ??
$C654	1 Byte	Gasha Seed Planted at ??
$C655	1 Byte	Gasha Seed Planted at ??
$C656	1 Byte	Gasha Seed Planted at K7
$C657	1 Byte	Gasha Seed Planted at ??
$C658	1 Byte	Gasha Seed Planted at ??
$C659	1 Byte	Gasha Seed Planted at ??
$C65A	1 Byte	Gasha Seed Planted at ??
$C65B	1 Byte	Gasha Seed Planted at M9

Mysterious Counter

$C65C - $C65D

A counter for ??? for which various actions increment

Action	Incrementation	Note
Dig a Hole	0x01
Slay an Enemy	0x03	This excludes using gale seeds on enemies, and knocking them into water/holes.
Collect a Heart	0x04
Screen Transition	0x05	This excludes entering/exiting structures, or taking mini-boss warps in dungeons.
Collect a Fairy	0x18
Bomb a Wall	0x32
Great Fairy Heal	0x40
Collect a Heart Piece	0x64

Dungeon Things

RAM	Length	Purpose	Note
$C662	1 Byte	Has entered Hero's Cave	Exiting a sublevel or using a mini-boss warp in the corresponding level will also set these flags (though redundant). [There's more to these addresses than originally thought. More exploration needed.]
$C663	1 Byte	Has entered Level 1: Gnarled Root Dungeon
$C664	1 Byte	Has entered Level 2: Snake's Remains
$C665	1 Byte	Has entered Level 3: Poison Moth's Lair (?)
$C666	1 Byte	Has entered Level 4: Dancing Dragon Dungeon (?)
$C667	1 Byte	Has entered Level 5: Unicorn's Cave (?)
$C668	1 Byte	Has entered Level 6: Ancient Ruins (?)
$C669	1 Byte	Has entered Level 7: Explorer's Crypt (?)
$C66A	1 Byte	Has entered Level 8: Sword & Shield Maze (?)

$C66E	1 Byte	Small Keys — Hero's Cave
$C66F	1 Byte	Small Keys — Level 1: Gnarled Root Dungeon
$C670	1 Byte	Small Keys — Level 2: Snake's Remains
$C671	1 Byte	Small Keys — Level 3: Poison Moth's Lair
$C672	1 Byte	Small Keys — Level 4: Dancing Dragon Dungeon
$C673	1 Byte	Small Keys — Level 5: Unicorn's Cave
$C674	1 Byte	Small Keys — Level 6: Ancient Ruins
$C675	1 Byte	Small Keys — Level 7: Explorer's Crypt
$C676	1 Byte	Small Keys — Level 8: Sword & Shield Maze

$C67A	1 Byte	Has Big Key(s)
$C67C	1 Byte	Has Compass(s)
$C67E	1 Byte	Has Dungeon Map(s)

Items

RAM	Length	Purpose	Note
$C680	1 Byte	Item on B Button
$C681	1 Byte	Item on A Button
$C682	1 Byte	Inventory Slot 1
$C683	1 Byte	Inventory Slot 2
$C684	1 Byte	Inventory Slot 3
$C685	1 Byte	Inventory Slot 4
$C686	1 Byte	Inventory Slot 5
$C687	1 Byte	Inventory Slot 6
$C688	1 Byte	Inventory Slot 7
$C689	1 Byte	Inventory Slot 8
$C68A	1 Byte	Inventory Slot 9
$C68B	1 Byte	Inventory Slot 10
$C68C	1 Byte	Inventory Slot 11
$C68D	1 Byte	Inventory Slot 12
$C68E	1 Byte	Inventory Slot 13
$C68F	1 Byte	Inventory Slot 14
$C690	1 Byte	Inventory Slot 15
$C691	1 Byte	Inventory Slot 16

RAM	Length	Purpose	Note
$C6A2	1 Byte	Current Hearts	This represents the current number of quarter-hearts the player has (each full heart is equal to 0x04). If this value is equal to or less than $C6A3 divided by this number (rounded up), the low health beep will play. The maximum value this will reach normally is 0x40. Values above 0x80 cause instant game over.
$C6A3	1 Byte	Max Hearts	This represents the maximum number of quarter-hearts the player can have (each full heart is equal to 0x04). This value, despite being counted in quarter-hearts, is always a multiple of 0x04 unlike $C6A2
$C6A4	1 Byte	Number of Heart Pieces	Valid values are 0x00 - 0x03. When a heart piece is collected while this value is at 0x03, this will be reset to 0x00, and $C6A3 will be increased by 0x04. This address will effect what is displayed on the the third screen of the start menu. If the value is set above 0x03, the graphics on that screen will progressively be filled with garbage.
$C6A5 - $C6A6	2 Bytes	Rupees	Value is represented in decimal. Example: If the total rupee count is 639, the hexadecimal representation will be 0x0639.
$C6A7 - $C6A8	2 Bytes	Ore Chunks
$C6A9	1 Byte	Shield level
$C6AA	1 Byte	Current Bombs	Value is represented in decimal.
$C6AB	1 Byte	Max bombs	Value is represented in decimal.
$C6AC	1 Byte	Sword level
$C6B1	1 Byte	Boomerang level
$C6B3	1 Byte	Slingshot level
$C6B2	1 Byte	Magnetic Gloves Polarity	Bits 1 2 3 4 5 6 7 8 0 = South 0 = Default Flute Graphics 0 = Dimitri Flute Graphics UNUSED UNUSED UNUSED UNUSED UNUSED 1 = North 1 = Ricky Flute Graphics 1 = Moosh Flute Graphics
$C6B4	1 Byte	Roc's feather level
$C6B5	1 Byte	Ember Seeds
$C6B6	1 Byte	Scent Seeds
$C6B7	1 Byte	Pegasus Seeds
$C6B8	1 Byte	Gale Seeds
$C6B9	1 Byte	Mystery Seeds
$C6BA	1 Byte	Gasha Seeds
$C6BB	1 Byte	Essences	Bits 1 2 3 4 5 6 7 8 Fertile Soil Gift of Time Bright Sun Soothing Rain Nurturing Warmth Blowing Wind Seed of Life Changing Seasons Each bit corresponds to an essence. The value of this address will be the sum of all the essences collected up to 0xFF. Example: If the value of this address is 0x1F, bits 1 - 5 are set, and the collected essences will be Fertile Soil, Gift of Time, Bright Sun, Soothing Rain, and Nurturing Warmth. Any value in this address is valid, but many of them will not normally be used unless essences are collected out of sequence. Assuming all essences are collected in sequence, the value will progress setting each bit in sequence, as follows: 0x00 -> 0x01 -> 0x03 -> 0x07 -> 0x0F -> 0x1F -> 0x3F -> 0x7F -> 0xFF
$C6CA	1 Byte	Vasu Ring Flags	Bits 1 2 3 4 5 6 7 8 Slayed 1,000 Monsters Collected 10,000 Rupees Saved the World UNUSED Slayer's Ring Rupee Ring Victory Ring UNUSED Based on what events have occurred, the above bits get set. Example: If the value is 0x03 (bits 1 & 2 are set), the player has collected 10,000 rupees and slayed 1,000 Monsters. In this scenario, if the value is 0x23 (bits 1, 2, and 6 are set) then the Slayers Ring has been received from Vasu as well.
$C6C6	1 Byte	Ring Box level

TBD

RAM	Length	Purpose	Note
$C700 - $C7FF	256 Bytes	Overworld Screen Flags (used to track events and map exploration)	Todo: Specify which each address tracks.
$CC30	1 Byte	Enemies left on screen
$CE00 - $CEAF		Current Screen Collision Data	Dynamically generated from the screen tile data. This space is also used as a temporary store for compressed level data read from ROM.
$CF00 - $CFAF		Current Screen Tile Data

Unmapped

RAM	Note
$C000 - $C5BF
$C600 - $C601
$C608 - $C615
$C620 - $C621
$C628 - $C639
$C63F	Shop 1 item flags?
$C640	Shop 2 item flags?
$C641	Maple flags?
$C642	Subrosian shop item flags?
$C643	Ricky flags?
$C644	Dimitri flags?
$C645	Moosh flags?
$C646 - $C64B
$C65E - $C661
$C66B - $C66C
$C677 - $C679
$C67B
$C67D
$C67F
$C692 - $C6A1
$C6AD - $C6B0
$C6BC - $C6C5
$C6C7 - $C6FF
$C800 - $CC2F
$CC31 - $CDFF
$CEB0 - $CEFF
$CFB0 - $CFFF