Posted By
JamesD
on 2016-09-26
11:12:56
|  Re: What would I do differently in the Plus/4
Is this the 4MHz C64 project you were talking about?
*edit*
Here is the project page, the csdb page I originally posted had some relevant comments but it also had a lot of drama.
projekt64:turbo
Here is the most important comment from the csdb page:
"...I've decided to force CPU to run at 2 Mhz at bad line, 3 Mhz at long/normal line, and 4 Mhz on borders. CPU power at 4Mhz mode is about 3.5 faster as is in 1Mhz mode. I found benchmark on internet (some FP calculations in BASIC) so 1Mhz takes 1m41s and 4Mhz mode takes 29s. ..."
I just want to point out that the CPLD he's using here, has more pins than the TED and possibly as many as the TED and CPU combined.
Doing this back in the day would have required a lot of high speed 74LS parts that may have been in short supply or a new TED.
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