This is new external interface based on big CPLD chip (XC95144XL or XC95288XL), ram memory 512kB-64MB, flash eprom 512kB, AY chip,SD card slot, RGB output.
This interface will work as expansion for SAM COUPE. Add compatibility with ZX 128kB models, DIVMMC (SD card) with ESXDOS system, possibility use any own ZX rom or SAM COUPE rom, soundchip AY-3-8910 for play ZX music. PCB contain some pinheads for possibility connect second PCB with other components (AY chip, etc...).
Interface use own external CPU Z80 processor (disable internal CPU and run only external CPU) for possibility change address bus lines. I plan add also own RGB output with more colors (upgrade SAM paletter from 128 to 256 colors). CPU may theoretically run at higher speed (turbo mode).
Second PCB may contain sockets for two AY chips (turbo-sound) and two SAA chips, D/A. New RGB output may be transparent or modified (possible convert 256x192 mode 4 with 16 colors per pixel to 128x192 mode with 256 colors per pixel.
Socket on board contain 40 pins and here is possible connect srandard sram 512kB or sram 2MB (M48Z2M1) or any other own module with smd sram chips up to 64MB capacity). This memory will contain copy of internal SAM COUPE ram 512kB (1:1) + next memory will be usable as standard 1MB expansions (up to 63x 1MB = 63MB ram). Other ram is used for rom replacement (rom emulation) or DIVMMC memory.
One of my highest priority is SAM COUPE snapshot support (snap full 512kB memory without destroy stack point memory).
