A2Z80plus is Z80 coprocessor card for APPLE II but, not just a card.
It has real Z80 CPU, RAM and interface port as a complete 8bits computer.
Basically, It designed to run up to 16Mhz Z80 board for compatible PCPI Appli-card
And has a expansion port with VDP-1000plus for extra fun games(This function is only for APPLE IIe).
It has flexible configurable structure to control Z80, Memory and I/O.
APPLE IIe could use this card as Memory card or I/O device.
Features;
Appli-card 128K compatible.
CP/M80 HDD booting as the 2nd photo.
APPLE IIe can direct access on Z80 memory and I/O.
APPLE II can control Z80 INT/NMI or Reset.
Z80 INT/NMI chain to 6502 IRQ under user configuration.
32KB 16banks (Total 512KB) can handle by APPLE IIe So, it can be used as memory card on APPLE IIe.
*MSX system ready
*Colecovision system ready
*SG1000 system ready
*those system code are ready to run but, need VDP and Sound I/O device to display it. anyway internally can run the code.
APPLE II and Z80 card runs isolated way not interfere each other.
Therefore user could run APPLE II program with full speed even if Z80 run or wait
So, Dual running could be abstained.
Compatible;
Works on APPLE ][, ][+
APPLE //e (128KB Recommended)
APPLE IIGS
*Z80 area RAM reading is only allowed APPLE //e model Other model can't perform reading only writing works.
PCPI CP/M working video is here.
Carefully compare to the BASIC running speed.