This is my old (2004) unfinished project of internal interface for ZX Spectrum 128+2:
(http://velesoft.speccy.cz/hardware_in_development.htm)
http://velesoft.speccy.cz/other/profi-2004.png
This is old specification:
PROFI INTERFACE FOR ZX128+2 (ISSUE 3 ONLY)
512kB-1MB SRAM + 128-512kB FLASH EPROM
emulation: ZX Profi 1024, Pentagon 128-1024, ZS Scorpion 256-1024
trdos mapping (work with ramdisc)
Actually is refresh work on this project. :v2_yahoo:
http://velesoft.speccy.cz/other/profi-2009-3d.jpg
http://velesoft.speccy.cz/other/profi-2009-top.jpg
http://velesoft.speccy.cz/other/profi-2009-bot.jpg
New board is redesigned and contain only one CPLD, 1MB SRAM, 512kB FLASH EPROM, Z80 CPU, battery CR2032. PROFI Interface work at 100%.
This is new specification:
512kB-1MB SRAM with battery backup
512kB FLASH EPROM
memory paging compatible with ZX Profi 1024, Pentagon 128-1024, ZS Scorpion 256-1024
TR-DOS mapping (work with ramdisc in PROFI or PENTAGON memory)
Speed-up slow ZX memory (contended memory pages)
Hardware unrainer and bug-fixer
Replacement of original chip HAL10H8
Next plans:
- rom emulation with extended ram
- DIVIDE interface emulation
- MB02 memory emulation
- software controlled NMI button
- memory paging compatibilty with all popular russian ZX CLONES
- russian CACHE emulation
- possibility disable acces to low 16kB for external peripherals
- more other features....