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by HeyLaughingBoy 1062 days ago
Fun project! "Back in the day" there was a speedup for the PC/AT called the Chang Modification: when the CPU was executing an internal instruction, the clock was switched to a faster one since internal memory didn't require wait states.

I noticed that there was a pin on the MC6809E that indicated whether the current instruction was accessing external RAM or running from registers and realized that I could do the same thing. A Chang-modified CoCo2. However, I was young and had far more projects than I could get to. Most of which I never finished... 30 years later I still have the same problem!

Anyway, the challenge is open if you want to take it up :-)

> Absolutely remarked AliExpress parts, but I do wonder what these used to be.

And this, ladies and gentlemen, is why we validate our Supply Chain :-)