Safety Manual for MPC5777M, Rev. 1.1
General information
NXP Semiconductors6
2.4 Correct operation
Assumption: [SCG18.010]Correct operation of the MPC5777M is defined as: [end]
• Assumption: [SCG18.011]Vital system modules (ViMos) and other supporting modules (SuMos)
are operating according to specification. [end]
• Assumption: [SCG18.012]Peripheral modules (PeMos) are operating according to specification.
[end]
• Assumption: [SCG18.013]Non-safety modules (NoSaMos) are not interfering with the operation
of other modules. [end]
• Other support modules (SuMo) are safety-relevant and in principle potential members of the
ViMos category, and cannot lead to a violation of the safety goal on their own. Typically, these will
only have multiple point faults, but not single point faults.
NOTE
[SCG18.902]See “Module classification” table in the MPC5777M
Reference Manual’s “Functional Safety” chapter for specific module safety
classification. [end]
2.5 Failure indication signaling
The Fault Collection and Control Unit (FCCU) offers a hardware channel to collect errors and to bring the
device to a Safe state
MCU
when a failure is present in the device. The FCCU provides two error output pins
(bidirectional FI[0] and FI[1], on PB[11] and PC[2], respectively) as a failure indication to the external
world.
Different protocols for the error output pins are supported:
• Dual rail protocol
• Time switching protocol
• Bi-stable protocol
If bi-stable protocol is selected, it is possible to use only one of the two error output pins on the
MPC5777M. Since the pin multiplexing that is utilized for each of the error output signals works
differently, FI[0] should be the signal used in this configuration.
After start-up reset, the error output signal FI[0] is in high impedance while FI[1] is functionally a GPIO
input with a weak pullup. The error output pins transition to the operational state only on software request.
A functional reset has no influence on FI[0] but sets FI[1] to high impedance with a pullup. To avoid
changing FI[1] during functional reset when time switching or bi-stable protocol is used, it is
recommended to write 0 to FCCU_CFG[PS].
Refer to Section 4.5, Error Out Monitor (ERRM) for details on specific requirements for connecting FI[0]
and FI[1] to an external device.
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