XC912BC32CFU8 Motorola Semiconductor Products, XC912BC32CFU8 Datasheet - Page 84

• Manufacturer Part Number: XC912BC32CFU8
• Description: M68HC12B Family Data Sheet
• Manufacturer: Motorola Semiconductor Products

Operating Modes and Resource Mapping
5.4.5 Miscellaneous Mapping Control Register
Data Sheet
84
Single-chip modes:
Expanded modes:
NOTE:
Reset states:
Address: $0013
Read:
Write:
Figure 5-5. Miscellaneous Mapping Control Register (MISC)
EE15–EE12 — Internal EEPROM Position Bits
EEON — EEPROM On Bit
Additional mapping controls are available that can be used in conjunction with
FLASH EEPROM/ROM and memory expansion.
The 32-Kbyte FLASH EEPROM/ROM can be mapped to either the upper or lower
half of the 64-Kbyte address space. When mapping conflicts occur, registers, RAM,
and EEPROM have priority over FLASH EEPROM.
Only the MC68HC912B32 contains FLASH EEPROM. The MC68HC12BE32
contains ROM.
To use memory expansion, the part must be operated in one of the expanded
modes.
Read: Anytime
Write: Once in normal modes; anytime in special modes
NDRF — Narrow Data Bus for Register-Following Map Bit
These bits specify the upper four bits of the 16-bit EEPROM address. Write
once in normal modes or anytime in special modes.
EEON allows read access to the EEPROM array. EEPROM control registers
can be accessed and EEPROM locations can be programmed or erased
regardless of the state of EEON.
EEON is forced to 1 in single-chip modes.
Write only in expanded and peripheral modes.
This bit enables a narrow bus feature for the 512-byte register-following map. In
expanded narrow (8-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 moves
also.
Bit 7
0
0
0
1 = EEPROM in memory map
0 = EEPROM removed from memory map
1 = Register-following map space acts the same as an 8-bit external data
0 = Register-following map space acts as a full 16-bit external data bus.
bus.
Operating Modes and Resource Mapping
NDRF
6
0
0
RFSTR1
5
0
0
RFSTR0
4
0
0
EXSTR1
3
1
1
EXSTR0
2
1
1
M68HC12B Family — Rev. 8.0
MAPROM
1
0
1
MOTOROLA
ROMON
Bit 0
0
1