PXS20RM Datasheet, PDF (530/1368 Pages) Freescale Semiconductor, Inc – PXS20 Microcontroller

Fault Collection and Control Unit (FCCU)
The CONFIG state is accessible only from NORMAL state and if the configuration is not locked.
The configuration lock can be disabled only by a global reset of the FCCU. The configuration shall
always be locked when running a safety critical application.
The CONFIG to NORMAL state transition can be executed by SW or automatically following a
time-out condition of the watchdog.
The incoming faults, occurring during the configuration phase (CONFIG state) are latched in order
to process them when the FCCU is moved into the NORMAL state, according to the selected
configuration.
• NORMAL: the FCCU operating state when no faults are occurring. It is also the default state on
the reset exit. The FSM will leave the NORMAL state following one of these events:
— Critical faults  the FCCU moves to the FAULT state
— Unmasked non-critical faults with the time-out disabled  the FCCU moves to the FAULT
state
— Unmasked non-critical faults with the time-out enabled  the FCCU moves to the ALARM
state
— Masked non-critical faults  the FCCU stays in NORMAL state
• ALARM: the FCCU moves into the ALARM state when an unmasked non-critical fault occurs and
the time-out is enabled. The transition to the ALARM state goes along with an interrupt. By
definition, this fault may be recovered within a programmable time-out period, before it generates
a transition to the FAULT state. The time-out is reinitialized if the FCCU state moves to the
NORMAL state. The time-out is stopped if the FCCU state moves to the FAULT state due to a
critical-fault occurring when the FCCU is in ALARM state. The time-out restarts following the
recovery from the FAULT state.
• FAULT: the FCCU moves into the FAULT state when one of the following condition occurs:
— Critical fault
— Time-out related to a non-critical fault when the FCCU is in the ALARM state
— Unmasked non-critical faults with the time-out disabled
• The transition from NORMAL/ALARM state goes along with the generation of:
— NMI interrupt
— FCCU_F signalling
— SAFE mode request after a certain amount of time
— SW option: Soft reaction (Short ‘functional’ reset)
— SW option: Hard reaction (Long ‘functional’ reset)
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PXS20 Microcontroller Reference Manual, Rev. 1
Freescale Semiconductor