MC68HC912BD32CFU10 FREESCALE [Freescale Semiconductor, Inc], MC68HC912BD32CFU10 Datasheet - Page 56

• Manufacturer Part Number: MC68HC912BD32CFU10
• Description: Advance Information
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

MISC — Miscellaneous Mapping Control Register
Operating Modes and Resource Mapping
MC68HC912BD32 Rev 1.0
RESET:
Bit 7
0
0
0
NDRF
6
0
0
This register can be read anytime. In Normal modes MISC can be written
once; in Special modes it can be written anytime.
NDRF — Narrow Data Bus for Register-Following Map
RFSTR1, RFSTR0 — Register-Following Stretch Bit 1 and Bit 0
EXSTR1, EXSTR0 — External Access Stretch Bit1 and Bit0
This bit enables a narrow bus feature for the 512-byte
register-following map. In Expanded Narrow (eight bit) modes, Single
Chip modes, and Peripheral mode, NDRF has no effect. The
register-following map always begins at the byte following the
512-byte register map. If the registers are moved this space will also
move.
These bits determine the amount of clock stretch on accesses to the
512-byte register-following map. It is valid regardless of the state of
the NDRF bit. In Single Chip and Peripheral modes this bit has no
meaning or effect.
These bits determine the amount of clock stretch on accesses to the
external address space. In Single Chip and Peripheral modes this bit
has no meaning or effect.
Freescale Semiconductor, Inc.
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0 = Register-following map space acts as a full 16-bit data bus
1 = Register-following map space acts the same as an 8-bit
RFSTR1
Stretch bit RFSTR1
Operating Modes and Resource Mapping
5
0
0
Table 12 Register-Following Stretch-Bit Definition
external data bus
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0
0
1
1
RFSTR0
4
0
0
EXSTR1
Stretch bit RFSTR0
3
1
1
EXSTR0 MAPROM ROMON
0
1
0
1
2
1
1
1
0
1
E Clocks Stretched
Bit 0
0
1
2
3
0
1
SIngle-chi
Ex. mode
p mode
$0013
10-mode