Intel 80C188XL - Manual (Page 167)

CHIP-SELECT UNIT
6-12
The UMCS and LMCS registers can be programmed in any sequence. To program the MCS and
PCS chip-selects, follow this sequence:
1. Program the MPCS register
2. Program the MMCS register to enable the MCS chip-selects.
3. Program the PACS register to enable the PCS chip-selects.
6.4.2 Programming the Active Ranges
The active ranges of the chip-selects are determined by a combination of their starting or ending
addresses and block sizes. This section describes how to control the active range of each chip-
select.
6.4.2.1 UCS Active Range
The UCS starting address is 100000H (1 Mbyte) minus the block size; its ending address is fixed
at 0FFFFFH.Table 6-2 defines the acceptable values for the field (U17:10) in the UMCS register
that determines the UCS block size and starting address.
Table 6-2. UCS Block Size and Starting Address
UMCS Field
U17:10
Block Size
(Kbytes)
Starting Address
00H 256 0C0000H
80H 128 0E0000H
C0H 64 0F0000H
E0H 32 0F8000H
F0H 16 0FC000H
F8H 8 0FE000H
FCH 4 0FF000H
FEH 2 0FF800H
FFH 1 0FFC00H