Intel 80C186EA User Manual page 181

CHIP-SELECT UNIT
Table 6-5. MCS Block Size and Start Address Restrictions
MPCS Block Size Bits
M6 M5 M4 M3
0 0 0 0
0 0 0 0
0 0 0 0
0 0 0 1
0 0 1 X
0 1 X X
1 X X X
X= don't care, but should be 0 for future compatibility.
Block Size is
defined by M6:0
Base + 3/4 Block Size
Base + 1/2 Block Size
Base + 1/4 Block Size
MCS Base
(Defined by U19:13)
6-14
Block Size
M2 M1 M0
0 0 1
0 1 X
1 X X
X X X
X X X
X X X
X X X
Starting Address
MCS3 Active Range
MCS2 Active Range
MCS1 Active Range
MCS0 Active Range
Memory Map
Figure 6-10. MCS3:0 Active Ranges
MMCS Start Address
(Kbytes)
8 None
16 U13 must be zero.
32 U14:13 must be zero.
64 U15:13 must be zero.
128 U16:13 must be zero.
256 U17:13 must be zero.
512 U18:13 must be zero.
NOTE: If U19 is one, will overlap UCS.
Ending Address
Base + (Block Size-1)
Base + (3/4 Block Size-1)
Base + (1/2 Block Size-1)
Base + (1/4 Block Size-1)
Restrictions
A1136-0C