Operating Modes
68HC(9)12DG128 Rev 1.0
66
Operating Modes
MOTOROLA
unintended operations, a write to one of these registers should be
followed with a NOP instruction.
If conflicts occur when mapping resources, the register block will take
precedence over the other resources; RAM or EEPROM addresses
occupied by the register block will not be available for storage. When
active, BDM ROM takes precedence over other resources, although a
conflict between BDM ROM and register space is not possible. The
following table shows resource mapping precedence.
The 68HC912DG128 contains 128K bytes of Flash EEPROM
nonvolatile memory which can be used to store program code or static
data. This physical memory comprises four 32k byte array modules,
00FEE32K, 01FEE32K, 10FEE32K and 11FEE32K. The 32K byte array
11FEE32K has a fixed location from $4000 to $7FFF and $C000 to
$FFFF. The three 32K byte arrays 00FEE32K, 01FEE32K and
10FEE32K are accessible through a 16K byte program page window
mapped from $8000 to $BFFF. The fixed 32K byte array 11FEE32K can
also be accessed through the program page window.
The 68HC12DG128 contains 128K bytes of ROM which can be used to
store program code or static data. This physical memory comprises four
32k byte array modules, 00ROM32K, 01ROM32K, 10ROM32K and
11ROM32K. The 32K byte array, 11ROM32K has a fixed location from
$4000 to $7FFF and $C000 to $FFFF. The three 32K byte arrays
00ROM32K, 01ROM32K and 10ROM2K are accessible through a 16K
byte program page window mapped from $8000 to $BFFF. The fixed
32K byte array 11ROM32K can also be accessed through the program
page window.
Table 12 Mapping Precedence
Precedence
Resource
1
BDM ROM (if active)
2
Register Space
3
RAM
4
EEPROM
5
On-Chip Flash EEPROM / ROM
6
External Memory
8-modes