Level One Memory System
ARM DDI 0363E Copyright © 2009 ARM Limited. All rights reserved. 8-7
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8.3 Fault handling
Faults can occur on instruction fetches for the following reasons:
• MPU background fault
• MPU permission fault
• External AXI slave error (SLVERR)
• External AXI decode error (DECERR)
• Cache parity or ECC error
• TCM parity or ECC error
• TCM external error
• TCM external retry request
• Breakpoints, and vector capture events.
Faults can occur on data accesses for the following reasons:
• MPU background fault
• MPU permission fault
• MPU alignment fault
• External AXI slave error (SLVERR)
• External AXI decode error (DECERR)
• Cache parity or ECC error
• TCM parity or ECC error
• TCM external error
• TCM external retry request
• Watchpoints.
Fault handling is described in:
• Faults
• Fault status information on page 8-9
• Correctable Fault Location Register on page 8-10
• Usage models on page 8-10.
8.3.1 Faults
The classes of fault that can occur are:
• MPU faults
• External faults on page 8-8
• Cache and TCM parity and ECC errors on page 8-8
• TCM external faults on page 8-8
• Debug events on page 8-9.
MPU faults
The MPU can generate an abort for various reasons. See MPU faults on page 7-12 for more
details. MPU faults are always precise, and take priority over other types of abort. If an MPU
fault occurs on an access that is not in the TCM, and is Non-cacheable, or has generated a
cache-miss, the AXI transactions for that access is not performed.