MC9S12NE64_06 Datasheet, PDF (430/554 Pages) Freescale Semiconductor, Inc – Microcontrollers

Chapter 16 Module Mapping Control (MMCV4)
16.3.2.4 Miscellaneous System Control Register (MISC)
7
6
5
4
3
2
R
0
0
0
0
EXSTR1 EXSTR0
W
Reset: Expanded
or Emulation
0
0
0
0
1
1
Reset: Peripheral
or Single Chip
0
0
0
0
1
1
Reset: Special Test
0
0
0
0
1
1
1. The reset state of this bit is determined at the chip integration level.
= Unimplemented or Reserved
Figure 16-6. Miscellaneous System Control Register (MISC)
1
ROMHM
0
0
0
0
ROMON
—¹
1
0
Read: Anytime
Write: As stated in each bit description
NOTE
Writes to this register take one cycle to go into effect.
This register initializes miscellaneous control functions.
Table 16-5. INITEE Field Descriptions
Field
Description
3:2
EXSTR[1:0]
External Access Stretch Bits 1 and 0
Write: once in normal and emulation modes and anytime in special modes
This two-bit field determines the amount of clock stretch on accesses to the external address space as shown in
Table 16-6. In single chip and peripheral modes these bits have no meaning or effect.
1
ROMHM
FLASH EEPROM or ROM Only in Second Half of Memory Map
Write: once in normal and emulation modes and anytime in special modes
0 The fixed page(s) of FLASH EEPROM or ROM in the lower half of the memory map can be accessed.
1 Disables direct access to the FLASH EEPROM or ROM in the lower half of the memory map. These physical
locations of the FLASH EEPROM or ROM remain accessible through the program page window.
0
ROMON
ROMON — Enable FLASH EEPROM or ROM
Write: once in normal and emulation modes and anytime in special modes
This bit is used to enable the FLASH EEPROM or ROM memory in the memory map.
0 Disables the FLASH EEPROM or ROM from the memory map.
1 Enables the FLASH EEPROM or ROM in the memory map.
Table 16-6. External Stretch Bit Definition
Stretch Bit EXSTR1
0
0
1
1
Stretch Bit EXSTR0
0
1
0
1
Number of E Clocks Stretched
0
1
2
3
MC9S12NE64 Data Sheet, Rev. 1.1
430
Freescale Semiconductor