Implement optional overclock for the 68000 #23
Closed
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Hello,
This modifications allows to overclock the MEGADRIVE 68000
COMBO-KEYS
START B A rises 0.5Mhz step
START B C downs 0.5Mhz step
From 8Mhz to 12.5Mhz
It works pretty well in a PAL MODEL 1600-18
not so well in PAL MODEL 1601-18 (Very unstable)
Hardware:
requires one external SPI function genrator
this one
AD9833 with 25Mhz reference frequency
or this one
AD9834 with 75Mhz reference frequency
also others could work
(changing the reference frequency in code is required)
GAMES
Games now run at the same speed but no more slowdown with many sprites on screen
games tested:
Street of rage 1, 2 & 3
Out Run
Super Hang ON
Sonic 1, 2 & 3
Aladin
Comix Zone
Dynamite Headdy
Gould'n Ghosts
Gunstar Heroes
Marble Land
Rocket Kinight Adventures
Megaman
Sparkster
Subterranea
Street Fighter 2 Turbo
Toe Jam & Earl
Thunder Force 3
Ristar
Contra Hard Corps
Castlevania Blood Line
Castle of Ilusion
Bubsy
Thanks