Chapter 1 Device Overview MC9S12XE-Family
MC9S12XE-Family Reference Manual , Rev. 1.19
80
Freescale Semiconductor
MPU is set, access to system resources is only allowed if enabled by a memory range descriptor as defined
in the Memory Protection Unit (MPU) description.
1.4.4.2
User State
This state is intended for carrying out system tasks and is entered by setting the U bit of the condition codes
register while in Supervisor state. Restrictions apply for the execution of several CPU instructions in User
state and access to system resources is only allowed in if enabled by a memory range descriptor as defined
in the Memory Protection Unit (MPU) description.
1.5
Security
The MCU security feature allows the protection of the on chip Flash and emulated EEPROM memory. For
a detailed description of the security features refer to the S12X9SEC description.
1.6
Resets and Interrupts
Consult the S12XCPU manual and the S12XINT description for information on exception processing.
1.6.1
Resets
Resets are explained in detail in the Clock Reset Generator (CRG) description.
Table 1-13. Reset Sources and Vector Locations
1.6.2
Vectors
lists all interrupt sources and vectors in the default order of priority. The interrupt module
(S12XINT) provides an interrupt vector base register (IVBR) to relocate the vectors. Associated with each
I-bit maskable service request is a configuration register. It selects if the service request is enabled, the
service request priority level and whether the service request is handled either by the S12X CPU or by the
XGATE module.
Vector Address
Reset Source
CCR
Mask
Local Enable
$FFFE
Power-On Reset (POR)
None
None
$FFFE
Low Voltage Reset (LVR)
None
None
$FFFE
External pin RESET
None
None
$FFFE
Illegal Address Reset
None
None
$FFFC
Clock monitor reset
None
PLLCTL (CME, SCME)
$FFFA
COP watchdog reset
None
COP rate select
Because
of
an
order
from
the
United
States
International
Trade
Commission,
BGA-packaged
product
lines
and
part
numbers
indicated
here
currently
are
not
available
from
Freescale
for
import
or
sale
in
the
United
States
prior
to
September
2010:
S12XE
products
in
208
MAPBGA
packages