Sinclair ZX80 / ZX81 / Z88 Forums

Designing a Homebrew ‘ZX Spectrum Plus’ Specification A real Z80 CPU at the core of the system, 128K or 512K SRAM with 64K ROM. A large CPLD such as an Altera EPM7512 as substitute for an enhanced ULA, the EPM7512 works at 5V on I/O lines, internal at 3.3V so can be interfaced easily with legacy CP...

This may ( or may-not ) be of interest to anyone into Electronics and building their own DIY homebrew Z80 : ZX Spectrum microcomputer ? I've talked a Chinese supplier into making homebrew DIY IC kits .. Homebrew ZX Spectrum kits are available : https://www.ebay.com/itm/Zilog-Z80-512K-ZX-Spectrum-Ho...

A ZX Spectrum with Real Chips ..like the original..is that too much to ask ? :idea: Why Not Design & Make a ‘New’ ZX Spectrum Super ULA ?? I was recently discussing the pros-and-cons of making a ASIC (application specific Integrated Circuit) and being told that it is an expensive thing..costing aro...

Why Not Design & Make a ‘New’ ZX Spectrum Super ULA ?? I was recently discussing the pros-and-cons of making a ASIC (application specific Integrated Circuit) and being told that it is an expensive thing..costing around $200,000 , and a minimum production run of tens of thousands of units being need...

Why Not Design & Make a ‘New’ ZX Spectrum Super ULA ?? I was recently discussing the pros-and-cons of making a ASIC (application specific Integrated Circuit) and being told that it is an expensive thing..costing around $200,000 , and a minimum production run of tens of thousands of units being neede...

A Simple ZX80 design using an inexpensive CPLD. Below is the parts list for a simple ZX80 homebrew microcomputer, based around a simple and cheap CPLD (EPM7128SLC84-15) . The CPLD having 60+ I/O Lines and 128 macroccells . These are just examples to give people ideas of what can b e done for theore...

Other ICs that I have are : again free to anyone that's building designing a homebrew ZX81 8-) Z80 CPUs .................................. DIP & PLCC Z80 KIO.................................... PLCC Z80 CTC.................................. DIP & PLCC Z80 SIO................................... DIP &...

Free to good home...... I've just found some CPLDs..which may be useful to anyone building a homebrew ZX81 around a CPLD. There's only a few so first come first served. I'll even post for free to anyone that's a serious homebrew builder/designer. CPLDs EPM7128SLC84-15 PLCC84 EPM9320LC84 PLCC84 EPM7...

Homebrew Builders: Sourcing ICs Something slightly off-topic and probably of interest to anyone new to homebrew microcomputer building. Sourcing ICS There’s many places to source Integrated Circuits (Chips).Here are just a few. Electronics Distributors : Large (or Small) electronics distributors : ...

If you are a homebrew builder looking for some FREE ICs... CPU,SRAM,EPROMs etc then look here :

http://www.mtxworld.dk/memorum/viewtopic.php?f=16&t=348

Dave's Website is here, were he can be emailed.

http://www.primrosebank.net/computers/mtx/mtx512.htm