Sonic the Hedgehog - FM - Mod - Hacks

Version	Date	By	IPS download	Size
1.02	6 Dec 2014	Valleybell	SonicTheHedgehog-SMS-FM-Mod-1.02.zip	10KB

Did you ever dream of playing the Master System version of Sonic 1 with FM music?

I did in 2011. And I made this hack to make this dream come true.

Features:

FM music using the YM2413 chip (PSG music can be toggled at the title screen by pressing the Pause button)
sound effects are still using the PSG, so they won't interrupt the music
a sound driver with many changes, including new commands, less per-channel RAM usage and FM support
an improved sound format that's about 20-30% smaller (all the additional code and music data fits within the 16 KB ROM bank used by the sound driver)
many easter eggs (i.e. hidden songs)
a few bug fixes to existing songs

Project History:

I remade most of the songs from Sonic 1 in 2011 using the OPLL/YM2413 and released VGMs of them on SMS Power!.
Although I never finished the whole set, I made a few OPLL remakes in 2012 that I never released. (like Green Hill Zone and the Ending Theme)
In 2013, Kroc disassembled the Sonic 1 SMS ROM, but required help with sound and music. So I decided to make a disassembly of the sound driver.
The work on this project effectively began on the 20th July 2014 by writing a small tool that would convert the original sound format to a more optimized one.
By the 23rd July the sound driver had fully working FM support and could read the new format properly.
The first FM song, Sky Base Act 2, was finished and compiled into the game on the 22nd July.
The first easter egg was added on the 24th July.

Thanks to:

Kroc for the Sonic 1 disassembly. I used it to find places where I could inject code to add all the easter eggs.
MAME Team for the MESS emulator and its debugger.

All Versions

file name	size (bytes)
total 5 files	3.3M
SonicTheHedgehog-SMS-FM-Mod-1.00.zip	10K
SonicTheHedgehog-SMS-FM-Mod-1.01-checksumfixed.zip	157K
SonicTheHedgehog-SMS-FM-Mod-1.01.zip	10K
SonicTheHedgehog-SMS-FM-Mod-1.02-source.zip	3.1M
SonicTheHedgehog-SMS-FM-Mod-1.02.zip	10K