PXD10RM Datasheet, PDF (940/1332 Pages) Freescale Semiconductor, Inc – PXD10 Microcontroller

by hardware. In order to switch from one mode to another, the application should access ME_MCTL
register twice by writing
• the first time with the value of the key (0x5AF0) into the KEY bit field and the required target mode
into the TARGET_MODE bit field,
• and the second time with the inverted value of the key (0xA50F) into the KEY bit field and the
required target mode into the TARGET_MODE bit field.
Once a valid mode transition request is detected, the target mode configuration information is loaded from
the corresponding ME_<mode>_MC register. The mode transition request may require a number of cycles
depending on the programmed configuration, and software should check the S_CURRENT_MODE bit
field and the S_MTRANS bit of the global status register ME_GS to verify when the mode has been
correctly entered and the transition process has completed. For a description of valid mode requests, please
refer to Section 25.4.5, Mode Transition Interrupts.
Any modification of the mode configuration register of the currently selected mode will not be taken into
account immediately but on the next request to enter this mode. This means that transition requests such
as RUN0…3  RUN0…3, DRUN  DRUN, SAFE  SAFE, and TEST  TEST are considered valid
mode transition requests. As soon as the mode request is accepted as valid, the S_MTRANS bit is set till
the status in the ME_GS register matches the configuration programmed in the respective
ME_<mode>_MC register.
SYSTEM MODES
software
request
software
request
SAFE
recoverable
hardware
failure
USER MODES
RUN0
RUN1
HALT
RESET
DRUN
non-recoverable
failure
TEST
RUN2
RUN3
STOP
25-34
STANDBY
Figure 25-24. MC_ME Mode Diagram
PXD10 Microcontroller Reference Manual, Rev. 1
Preliminary—Subject to Change Without Notice
Freescale Semiconductor