A weblog focused on interesting circuits, ideas, schematics and other information about microelectronics and microcontrollers.
E-books
Disclaimer
Because I have not tested all electronic circuits mentioned on this pages, I cannot attest to their accuracy; therefore, I do not provide a warranty of any kind and cannot be held responsible in any manner.
External 128-512 kB RAM for ZX Spectrum
19. March 2009 - 19:30 — admin
ZX Spectrum is still alive - at least in the Czech Republic. :) Here is a Velesoft's (nearly) unobtrusive solution for ZXS memory enhancing (in English, don't worry).
I must say I like Velesoft's work - his circuits are minimal obtrusive and 27 years old ZX Spectrum meets the modern chips in them. For example this one... With one GAL, one 74HCT273 and one memory chip it provides the ZX128/+2/Pentagon compatible paging (at port #7FFD). It's totally unobtrusive if you have the ZXS 16kB version; with 48k version you have to remove (or disable) internal upper RAM (yes, yes, it's a little bit obtrusive, I know).