EXPANSION CARD #1:
1090 CP/M Module. (This was to be the 1090 version of the "Sweet-Pea"
which was an external box called the Atari 1060 CP/M Add-on.
The 1090 CP/M card is the Atari 1066.) This expansion card
would have allowed an Atari computer to run software written for Zilog
Z-80 processor CP/M (Control Program for Microcomputers) computers.
The card contains a Zilog Z-80 processor and support circuitry.
However this board has not been able to be tested since no software drivers
have yet been found. The card does contain an expansion header,
it is unknown whether or not this header may have been used for a daughter
card with RAM or perhaps a floppy disk controller board or some other feature.
EXPANSION CARD #2:
80 Column Video Module. This is a bare unfinished board.
It capabilities are unknown. Whether or not it had character attributes
and multiple split screens similar to the Atari Corp XEP80 80 column/parallel
port module is unknown. However it is most likely a necessary
board in conjunction with the CP/M module since most CP/M software would
have functioned more properly in an 80 column mode.
EXPANSION CARD #3:
64K Memory Module. Up to 3 of these modules could have resided within
the 1090XL expansion chassis. They would be daisy chained together
via the expansion header located in the top center of the card. The
card had 2 "Personality" modes. One mode was the "Bank Switching"
mode for use with the 800XL, 1400XL and 1450XLD. The second mode
was the "1064" mode which would have allowed a single memory card to act
as a 1064 expansion module. (The 1064 Expansion module was a 64K box
which could only plug into an Atari 600XL giving it 80K of total memory).