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E • 5
ntDD RBGISTBR (PORT
OBBII) ••••• Wr i te
only
In the standard EM unit, index address 50 and 51 are used in
its index register.
After using the index address, BIOS always clears to
"0",
so
that content of the data register should not be changed by
any other program except BIOS.
E. 6 Ell CmlPIGORA'l'ION REGIS'l'ER- 0 (Index 50/(0)
E. 6 • I
<
Wr
i
te>
Within
thi~
register, I/O address of the EM unit is set by
the bits 3-0 of the EMU port, while bits 7-4 are not used.
Bit
1/0 Address
3
2
1
0
(When Power is on)
0
0
0
0
208H - 20FH
0
0
0
1
218H - 21FH
0
1
0
1
258H - 25FH
0
1
1
0
268H - 26FH
1
0
1
0
2A8H - 2AFH
1
0
1
1
2B8H - 2BFH
1
1
1
0
2E8H - 2EFH
X
1
1
1
Disable*
Note: *Disable
=
Read/Write operation towaards the
expansion memory is disabled.
E - 8
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