MC9S12T64 Datasheet, PDF (135/608 Pages) Motorola, Inc – Specification

Freescale Semiconductor, Inc.
Module Mapping Control (MMC)
Functional Description
in the MISC register during reset. In particular, one can also disable
access to the first half of the FLASH EEPROM (locations $0000 - $7FFF)
by setting the ROMHM bit. Although the CALRAM can also be disabled,
ultimately it is the enabling condition FLASH EEPROM that determines
if access will be external or internal. This is true because the FLASH
EEPROM covers all the MCU address space and has a selection priority
only superior to external accesses (See Table 26). Table 27 summarizes
the conditions necessary for an access to be internal/external in
expanded modes.
Table 27 Access Type in Expanded Modes
ROMON
/ROMHM
MCU Address
Range
Type of Access
Normal Mode
Special Mode
1/0
$0000–$FFFF
Internal
Internal
External only if
External only if
$0000–$7FFF
internal resources internal resources
1/1
cannot be accessed cannot be accessed
$8000–$FFFF
Internal
Internal ⁽¹⁾
External only if
External only if
0/x
$0000–$FFFF
internal resources internal resources
cannot be accessed cannot be accessed
1. Accesses to all Flash pages, even to the ones disabled ($3D,$3E) by ROMHM bit, are al-
lowed through the Program Page Window ($8000 <= MCU address <= $BFFF).
Emulation Chip
Select (ECS) Signal
Functionality
When the EMK bit in the MODE register is set, Port K bit 7 is used as an
active-low emulation chip select signal, ECS. This signal is active when
the system is in Emulation mode, the EMK bit is set and the Flash
EEPROM or ROM space is being addressed. When the EMK bit is clear,
this pin is used for general purpose I/O.The ECS signal functions based
upon the assigned memory allocation. The operation of the ECS signal
depends upon the state of the ROMHM bit in the MISC register. Table 28
below summarizes the functionality of these signals based upon the
allocated memory configuration.
Table 28 64K Byte Physical Flash/ROM Allocated
Address Space
$0000 - $7FFF
ROMHM
0
1
ECS
0
1
MOTOROLA
Module Mapping Control (MMC)
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MC9S12T64Revision 1.1.1
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