MC68HC812A4 Datasheet, PDF (89/342 Pages) Motorola, Inc – 16-bit device composed of standard on-chip peripheral modules connected by an intermodule bus. Modules include

Operating Modes and Resource Mapping
Mode and Resource Mapping Registers
Address: $0012
Bit 7
6
5
4
3
2
1
Read:
EE15 EE14 EE13 EE12
0
0
0
Write:
Reset:
Expanded and peripheral: 0
0
0
1
0
0
0
Single-chip: 1
1
1
1
0
0
0
Figure 5-4. EEPROM Initialization Register (INITEE)
Bit 0
EEON
1
1
Read: Anytime
Write: Varies from bit to bit
EE15–EE12 — EEPROM Position Bits
These bits specify the upper four bits of the 16-bit EEPROM address.
Normal modes: Write once
Special modes: Write anytime
EEON — EEPROM On Bit
EEON enables the on-chip EEPROM. EEON is forced to 1 in
single-chip modes.
Write anytime
1 = EEPROM at address selected by EE15–EE12
0 = EEPROM removed from memory map
5.5.5 Miscellaneous Mapping Control Register
Additional mapping controls are available that can be used in
conjunction with memory expansion and chip selects.
To use memory expansion, the part must be operated in one of the
expanded modes. Sections of the standard 64-Kbyte memory map have
memory expansion windows which allow more than 64 Kbytes to be
addressed externally. Memory expansion consists of three memory
expansion windows and six address lines in addition to the existing
standard 16 address lines. The memory expansion function reuses as
Advance Information
MOTOROLA
Operating Modes and Resource Mapping
MC68HC812A4 — Rev. 3.0
89