overclock switch suggestions

So i'm looking at doing an overclock mod for my dreamcast but want to be able to switch it back to its default if playing a game where it's not helpful. Does anyone have any suggestions for a simple 2 way switch that can install securely? I've seen quite a few using rounded chrome plated ones. Any suggestions of a good supplier for stuff like this would also be appreciated.

 

A passive switch will not allow you to switch between two clock signals in a reliable way.

Switches "bounce"-- they make and break contact many times after being flipped in an unpredictable way. This increases the already high risk of a glitch from metastability issues, which are inherent to switching between two oscillators without a fixed phase relationship and at a safe hand-off point. Otherwise you'll end up with "runt pulses" which violate the setup and hold times of subsequent synchronous logic. Clock glitches may be tolerated a few times before a crash, but a crash is inevitable without taking precautions.

This is a pretty complicated subject so I'd suggest looking for premade clock multiplexer ICs, but even they are hard to select and use because this is such a rare application.

 

Thanks for the tips. It looks like an oscillator will be enough to overclock the cpu. I have no plans on switching between two clock speeds while the machine is running. I only planned on using the overclock when playing multiplayer games that are a bit sluggish (4 player unreal tournament comes to mind...) and for geist force

 

I made that an eon and a half ago, it might be useful to you:



You can buy those switch pretty much anywhere that sell electronics and any Single Pole Double Throw (SPDT) switch would work. Check ebay for bargains.