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LSDJ RAM Dump stuff

Started by charon the ferryman, 30, June, 2015, 02:21:25 PM

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charon the ferryman

LSDJ is a tracker for the Gameboy that allows players to create their own chiptunes with it. I've done quite a bit of music with this nifty piece of software and I can say it's pretty dang awesome. Unfortunately, being a Gameboy game, it's completely inaccessible outside of memorization. So I may be writing a specific GB emulator that will allow blind musicians to explore this pretty awesome tool.

I may just make it so that you can write your own files and then just load it into VBA but whatever, I found these, so have fun.

Anyways, I'm dumping my findings here, so hopefully someone else finds it useful.

LSDJ Memory Values:

0xB290-0xB68F

On the SONG screen, these values include the values of the various Chains.

These values do NOT reflect the actual values on any other screen. This should only be referenced when SONG is the active screen.

Each 4 bytes indicates a row of Chains. For example, the first byte in a set of 4 is PU1, then PU2, then WAV, then NOISE. Then it repeats until reaching FF.

These values seem to be stored elsewhere when not on the SONG screen, but I can't find them.

Idea: Extract these values when SONG is first loaded and place them in an array for quick access while on this screen, and flush the array when the screen changes.

0xA080-0xA87F

On the CHAIN screen, these values include references to various phrases.

These values do not reflect the actual values on any other screen. This should only be references when CHAIN is the active screen.

Each 16 bytes reflects a single chain. Chain 00 starts at A080, chain 01 starts at A090 ect.

These values are stored elsewhere but I can't find them.

Idea: Extract these values when CHAIN is first loaded and place them in an array for quick access while on this screen, and flush the array when the screen changes. Only reference the CURRENTLY SELECTED CHAIN.

0xA880-0xB07F

On the CHAIN screen, these values are the pitch offset for each individual phrase.

Similar to the references to the phrases, each 16 bytes corresponds with each chain. So A880 is chain 00, A890 is chain 1 ect.

0xA000-0xAFEF

On the PHRASE screen, represents the various notes. C3 (the lowest note) is represented with 01 while the highest note, B8, is represented by 48.

This has a weird update format. When deleting a note, it completely erases all the notes. This also occurs if you insert the same note. Adding the same instrument clears the memory as well. The list is resorted when you change the current note.

Each 16 bytes represents a single phrase. A000 is Phrase 00, A010 is phrase 01, ect.

0xC0AD

Current screen. Values correspond to:

01 - PHRASE screen
02 - GROOVE screen
03 - CHAIN screen
04 - SONG screen
05 - TABLE screen
06 - INSTRUMENT Screen
08 - FRAME screen
09 - PROJECT screen
0A - BANK screen

I might be missing a few, it's always tricky to go and figure this one out. lol

0xC1EF

5 character string representing currently selected instrument's name. Only applicable on INSTRUMENT screen.

The following are values that monitor the cursor. They stay the same when switching screens unless otherwise specified.

0xC1CC

PHRASE screen:

Horizontal cursor position. Starts at 1. 1 is note, 2 is instrument, 3 is type of modulation and 4 is modulation modifier.

0xC1CD

PHRASE screen:

Vertical cursor position.

0xC1D2

CHAIN screen:

Horizontal cursor position. 0 is chain, 1 is transpose.

0xC1D3

CHAIN screen:

Vertical cursor position.

0xC1D7

SONG screen:

Horizontal cursor position.

0xC1D8

SONG screen:

Vertical cursor position.