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ROM
Adapter |
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This
ROM Adapter plugs into the ROM socket on the
Memory-2 Board replacing the default 256K x 16 (27C4096)
ROM with a larger 2048K x 16 (27C322) ROM.
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Additional
68000 bus signals i.e. A21, A20, and A19 must be routed
to HDR1 on the ROM Adapter from the system backplane
headers using fly leads. |
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Signal
|
Backplane Header |
ROM
Adapter HDR1 |
| 68000
bus - A21 |
H1 pin 29 |
A20 |
| 68000
bus - A20 |
H2 pin 29 |
A19 |
| 68000
bus - A19 |
H1 pin 28 |
A18 |
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To map all 4MB
of the 27C322 ROM into the upper 4MB region of the
68000's
address space, a modification to the address decoding on
the Memory-2 Board is required. IC2 controls address
decoding on the Memory-2 Board and IC2 is an
electrically erasable programmable logic device thus a
simple firmware update is all that is required. This
firmware update (gal8d.jed) and instructions on
programming IC2 can be found here: |
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Memory-2/Firmware |
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| Note: |
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For correct operation of the ROM Adapter, JB1 on the
Memory-2 Board MUST be set as follows: |
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| JB1 pins
1-2 open, 3-4 short, and 5-6 open |
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