Freescale Semiconductor, Inc.
Operating Modes and Resource Mapping
5.5.4 Miscellaneous System Control Register
Additional mapping and external resource controls are available. To use
external resources the part must be operated in one of the expanded
modes.
Bit 7
6
5
4
3
2
1
Bit 0
MAPROM
NDRF
RFSTR1 RFSTR0 EXSTR1 EXSTR0 ROMON28 ROMON32
RESET:
RESET:
0
0
0
0
0
0
0
0
1
1
1
1
0
1
0
1
Exp Modes
SC Modes
MISC — Miscellaneous Mapping Control Register
$0013
Normal modes: write once; Special modes: write anytime. Read
anytime.
MAPROM — Map Location of ROM
This bit is used to swap the location of the on-chip Flash EEPROM
(68HC912D60) or ROM (68HC12D60) arrays.
0 = 28K byte array is mapped from $1000 to $7FFF, 32K byte array
is mapped from $8000 to $FFFF.
1 = 28K byte is mapped from $9000 to $FFFF, 32K byte array is
mapped from $0000 to $7FFF.
NDRF — Narrow Data Bus for Register-Following Map Space
This bit enables a narrow bus feature for the 512 byte Register-
Following Map. This is useful for accessing 8-bit peripherals and
allows 8-bit and 16-bit external memory devices to be mixed in a
system. In Expanded Narrow (eight bit) modes, Single Chip Modes,
and Peripheral mode, this bit has no effect.
0 = Makes Register-Following MAP space act as a full 16 bit data bus.
1 = Makes the Register-Following MAP space act the same as an 8
bit only external data bus (data only goes through port A externally).
The Register-Following space is mapped from $0200 to $03FF after
reset, which is next to the register map. If the registers are moved this
space follows.
Advance Information
84
68HC(9)12D60 — Rev 4.0
Operating Modes and Resource Mapping
MOTOROLA
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MOTOROLA [ MOTOROLA ]
