MC68HC11F1 Datasheet, PDF (41/68 Pages) Motorola, Inc – Technical Summary 8-Bit Microcontroller

Bit 5 — Not implemented. Reads always return zero and writes have no effect.
GNPOL — General-Purpose Chip-Select Polarity
0 = CSGEN is active low
1 = CSGEN is active high
GAVLD — General-Purpose Chip-Select Address Valid
0 = CSGEN is valid during E-clock valid time (E-clock high)
1 = CSGEN is valid during address valid time
GSIZ[A:C] — Block Size for CSGEN
Refer to Table 20 for bit values.
Table 20 General-Purpose Chip Select Size Control
GSIZ[A:C]
000
001
010
011
100
101
110
111
Address Size
64 Kbytes
32 Kbytes
16 Kbytes
8 Kbytes
4 Kbytes
2 Kbytes
1 Kbyte
0 Kbytes (disabled)
MC68HC11F1/FC0
MC68HC11FTS/D
MOTOROLA
41