Reset switch for finding Konami cheats

Door Gregory

Master (178)

afbeelding van Gregory

19-05-2021, 11:25

I stumbled upon this page on the net:

Could someone give some more detail on how about the memory extension and the switch work? Or is there a schematic available for this?

It's... a memory extension with a switch. Yeps. On/off. I forgot which line the switch is supposed to be on, but ask this on the MSX-newsgroup and probably someone can tell you. How does it work? Well, when you put the switch "off", and boot the computer, it cannot find the memory extension and boots from normal ram. Now run your program, or the program you want to hack. Flick the switch to "on". Now wait until the program is in the phase you want to examine, (or just wait till your buggy program hangs,) and reset your computer!!

What happens is this: on booting, your computer now finds RAM first in your memory extension, thereby completely ignoring the contents of the computer-ram. When you now run "wbass" or something, selecting the slots correctly shows you all ram, including the high system area (.. such as stack pointer areas, fd9a/fd9f vector usage) exactly as it was when you resetted the computer! It's a really good trick. (Credits for this method should go to Emiel Hensen, who was Dr.Venom in Sigma. Way back, this.)

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Van sdsnatcher73

Prophet (2329)

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19-05-2021, 11:39

My guess would be SLTSL or the 5V line(s).

Van Pencioner

Scribe (1479)

afbeelding van Pencioner

19-05-2021, 11:50

I bet the right slotexpander with switches for subslots like Modulon and memory mapper of bigger RAM size than your computers' mapper will do the trick easily