mc9s12ne64 Freescale Semiconductor, Inc, mc9s12ne64 Datasheet - Page 410

• Manufacturer Part Number: mc9s12ne64
• Description: Hcs12 Microcontrollers Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

Chapter 15 Multiplexed External Bus Interface (MEBIV3)
410
MOD[C:A]
Field
EMK
EME
IVIS
7:5
3
1
0
Mode Select Bits — These bits indicate the current operating mode.
If MODA = 1, then MODC, MODB, and MODA are write never.
If MODC = MODA = 0, then MODC, MODB, and MODA are writable with the exception that you cannot change
to or from special peripheral mode
If MODC = 1, MODB = 0, and MODA = 0, then MODC is write never. MODB and MODA are write once, except
that you cannot change to special peripheral mode. From normal single-chip, only normal expanded narrow and
normal expanded wide modes are available.
See
Internal Visibility (for both read and write accesses) — This bit determines whether internal accesses
generate a bus cycle that is visible on the external bus.
Normal: write once
Emulation: write never
Special: write anytime
0 No visibility of internal bus operations on external bus.
1 Internal bus operations are visible on external bus.
Emulate Port K
Normal: write once
Emulation: write never
Special: write anytime
0 PORTK and DDRK are in the memory map so port K can be used for general-purpose I/O.
1 If in any expanded mode, PORTK and DDRK are removed from the memory map.
In single-chip modes, PORTK and DDRK are always in the map regardless of the state of this bit.
In special peripheral mode, PORTK and DDRK are never in the map regardless of the state of this bit.
Emulate Port E
Normal and Emulation: write never
Special: write anytime
0 PORTE and DDRE are in the memory map so port E can be used for general-purpose I/O.
1 If in any expanded mode or special peripheral mode, PORTE and DDRE are removed from the memory map.
In single-chip modes, PORTE and DDRE are always in the map regardless of the state of this bit.
Removing the registers from the map allows the user to emulate the function of these registers externally.
Table 15-8
and
Table
15-16.
Table 15-7. MODE Field Descriptions
MC9S12NE64 Data Sheet, Rev. 1.1
Description
Freescale Semiconductor