Ast A. Moore wrote: ↑Wed Dec 12, 2018 10:44 pmSure, I understand that. But what’s the point of having a Spectrum, and why would you shelve it if it didn’t play ball with the DivMMC? I mean, I have a couple of Spectrums and no DivMMC or any other SD-card interface for them.
I may like the look of the hardware, but that doesn't mean I want to fiddle with cassettes and audio cables. That was NOT a fun part of owning an 80s 8-bit.
Thanks for the tip on the test program. I'll give that a shot when I get home.These are likely CMOS Z80s. Most (all?) original Spectrums came with an NMOS Z80 cpu. If I were you, I’d get the 6 MHz version, or even look online for an old-sock NMOS 4 MHz one. There’s no advantage of getting a higher-clock CPU here.
The thing is, the 6,8, and 10MHz chips are all the same price, and the 20MHz chip is only $3 more. So unless there's a good reason the better rated chip *won't* work, I intend to buy that. Typcically, there's no architectural difference between the slower and faster rated chips; the slower ones are just chips that didn't pass when tested at higher speeds.
What worries me is that there might be some electrical difference... can I just drop a CMOS CPU into a socket formerly occupied by an NMOS version?