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Arm

CoreLink™ GIC-600AE Generic Interrupt Controller

Technical Reference Manual

Document ID: 101206_0003_04_en

Issue: 04

Functional Safety

•

Possible lockup on external buses that causes the GIC blocks and internal interconnect to stall.

The source of the lockup might be software issues, DoS issues, or systematic faults in the silicon.

Related information

Ping mechanisms on page 202

6.13 DFT protection

Functional Safety Mechanisms have been added to protect the MBIST and ATPG Scan logic from

faults during functional mode.

6.13.1 MBIST

The MBIST wrapper logic built into GIC-600AE is duplicated, which lets the mechanism detect

faults in this logic.

For example, it can detect a fault on a RAM address bit. It can detect the fault due to the

comparators at the inputs of the shared RAMs.

The following MBIST interface inputs can cause mission-mode errors, so they are protected.

Table 6-13: Protected MBIST inputs

Signal Protection Notes

mbistreq Assertion

detection

If the mbistreq signal is asserted when the GIC block is in functional mode, the GIC detects and reports it. If this

assertion happens in MBIST mode, we assume that software ignores and clears the fault, either through a reset

or the FMU clearing mechanism. Alternately, to prevent the fault from asserting, software can disable the SM

before entering MBIST mode.

nmbistreset Duplication The reset is duplicated. The duplicated reset signal is nmbistreset_fdc. For a reset to occur, both the nmbistreset

and nmbistreset_fdc signals must assert. See 6.5.2 Resets on page 213 for more information.

The MBIST interface pins themselves are unchanged from GIC-600.

The other MBIST inputs, including the mbistaddr and mbistindata signals, are benign and cause no

harm if they experience faults during functional mode.

If faults occur on the MBIST controller or MBIST signals, it is assumed the MBIST controller detects

them.

Non-Conﬁdential

Page 247 of 268

ARM CoreLink GIC-600AE User Manual

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