Intel 80C186EA User Manual page 170

Internal
Address Bus
= Block Size
= Block Size
= Block Size/4
= Block Size/4
= Base
= Block Size/4
= Block Size/4
= Base
Memory/
I/O Selector
MS
UCS
LCS
MCS3
MCS2
MCS1
MCS0
Base + 0
Base + 128
Base + 256
Base + 384
Base + 512
Base + 640
Base + 768
Internal Address Bit
Figure 6-2. Chip-Select Block Diagram
CHIP-SELECT UNIT
PCS0
PCS1
PCS2
PCS3
PCS4
A
MUX
A1
B
A2
EX Control Bit
PCS5
A/B
PCS6
A1139-0A
6-3