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E.6.2 <Read>
Bits 7-4 of this register shows the
10
bits 3-0 of the EM
unit, and these
10
codes are used to keep the compatibility
with the up-revisioned EMU in the future.
The
10
of the
current EM unit is 8H.
By bits 3-0 of this register, I/O port address set on
writing is read.
E.7 EM CONFIGURATION REGISTER - 1 (Index 51/61)
E.7.l <Write>
Bits 7-6 (Not used)
Bit 5 (Not used)
Bits 4-0 •..•• Hard RAM bits 4-0
These are the bits used when expansion memory is used
as the Hard RAM.
The expansion memory with the following capacity is
used as the Hard RAM.
Bit
Real memory capacity
4
3
2
1
0
of the EM
0
0
0
0
0
0
0
0
0
0
1
64 kbytes (4 pages)
0
0
0
1
0
128 kbytes (8 pages)
S
S
S
S
S
S
1
1
1
1
1
2 Mbytes (128 pages)
These bits 4-0 are not used as hardware of the EM, but
as software (RMM, SYS, BIOS).
From the hardware's point of view, it can be seen as if
simply Read/Write possible register exists.
E.7.2 <Read>
The contents written in the register can be read out.
E -
9
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