MC68HC812A4 Datasheet, PDF (139/342 Pages) Motorola, Inc – 16-bit device composed of standard on-chip peripheral modules connected by an intermodule bus. Modules include

Memory Expansion and Chip-Select
Chip-Select Registers
CS3EP — Chip-Select 3 Follows Extra Page
1 = Chip-select 3 follows accesses to the 1-Kbyte extra page
($0400 to $07FF or $0000 to $03FF). Any accesses to this
window cause the chip-select to go active. (EWEN must be set
to 1.)
0 = Chip-select 3 includes only accesses to a 128-byte space
following the register space.
8.7.3 Chip-Select Stretch Registers
Each of the seven chip-selects has a 2-bit field in this register which
determines the amount of clock stretch for accesses in that chip-select
space.
Read: Anytime
Write: Anytime
Address: $003E
Bit 7
6
5
4
3
2
1
Bit 0
Read: 0
Write:
0
SRP1A SRP1B SRP0A SRP0B STRDA STRDB
Reset: 0
0
1
1
1
1
1
1
= Unimplemented
Figure 8-18. Chip-Select Stretch Register 0 (CSSTR0)
Address: $003F
Bit 7
6
5
4
3
2
1
Bit 0
Read:
STR3A
Write:
STR3B
STR2A
STR2B
STR1A
STR1B
STR0A
STR0B
Reset: 0
0
1
1
1
1
1
1
Figure 8-19. Chip-Select Stretch Register 1 (CSSTR1)
Advance Information
MOTOROLA
Memory Expansion and Chip-Select
MC68HC812A4 — Rev. 3.0
139