Computer (EPC) Index
EXM - EXpansion Module
EPC-21 / -22 Manuals
Manuals for -21 and -22 are the same.
Inserting an EPC into an EXM
Note: Make sure that
power to your system is off. The EPC-23 is not designed to
be inserted or removed from a live system.
Notice: Use of any of
the files or information on this page is
AT YOUR OWN RISK. If you want
a guarantee on this stuff, seek out any repair / service
company that supports EXM / EPC devices.
If you have any files or experience with these devices, please reach to
Supposedly, the -21 and -22 models were offered with:
-21 386SL-16, no 64KB cache and no 387SX
-22 386SL-25, 64KB cache, 387SX, and 0MB / 1MB / 4MB Base
EPC-16 4MB Base Memory,
0KB cache, no 387SX
EPC-22 0MB Base Memory,
64KB cache, no 387SX.
EPC-22 386SL-25, 4MB
Base Memory, 64KB cache, 387SX.
Intel386 SL Microprocessor SuperSet
KU82360SL Complete ISA Peripheral Subsystem Advance
KU80386SL 386SL CPU
The two ICs under the center of the SIMM are the 64KB cache,
CY7C195-25VC 64K x 4 Static RAM datasheet
64 KB four-way set-associative write-through cache.
Memory writes from the 386SL that hit the cache (find the
addressed location in the cache) also write into the DRAM.
0 to 640K are cached
640K to 1M are not cached.
1M to top of installed memory are cached
[except for a secondary graphics frame buffer
like on the EXM-14 Live video board].
Base Memory 1MB or 4MB
1 MB uses 2 4Mb chips (256K by 18-bit banks). 40 pin chips don't use the
4 MB uses 2 16Mb chips (1MB x 18-bit banks). 42 pin chips use all pads.
say this memory architecture supports a 16MB SIMM. YMMD.
EPC-22 Base Memory
EPC-21 / -22 Memory Amounts
0MB Base Memory, 2MB, 4MB or 8MB SIMM, max 8MB.
1MB Base Memory, 2MB, 4MB or 8MB SIMM, max 9MB.
4MB Base Memory, 2MB, 4MB, 8MB or 16MB SIMM, max 20MB.
Floppy Types Supported
360K, 720K, 1.2 MB, 1.44MB, and 2.88 MB. BUT... If you look
at the EMC-FDM, it appears to have a max 500Kbit/s transfer
rate, which suggests to me that it tops out at 1.44MB