U Fault s a n d C P U a b o r t s

WO R K I N G W I T H T H E C P U

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MMU faults and CPU aborts. .

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M M U f a u l t s a n d C P U a b o r t s

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The MMU generates an abort on these types of faults: Alignment faults (data accesses only) Translation faults

Domain faults Permission faults

In addition, an external abort can be raised by the external system. This can happen only for access types that have the core synchronized to the external system:

Alignment fault checking

Fault Address and Fault Status registers

Page walks

Noncached reads

Nonbuffered writes

Noncached read-lock-write sequence (SWP)

Alignment fault checking is enabled by the A bit in the R1: Control register. Alignment fault checking is not affected by whether the MMU is enabled. Translation, domain, and permission faults are generated only when the MMU is enabled.

The access control mechanisms of the MMU detect the conditions that produce these faults. If a fault is detected as a result of a memory access, the MMU aborts the access and signals the fault condition to the CPU core. The MMU retains status and address information about faults generated by the data accesses in the Data Fault Status register and Fault Address register (see “Fault Address and Fault Status registers” on page 119).

The MMU also retains status about faults generated by instruction fetches in the Instruction Fault Status register.

An access violation for a given memory access inhibits any corresponding external access to the AHB interface, with an abort returned to the CPU core.

On a data abort, the MMU places an encoded four-bit value — the fault status — along with the four-bit encoded domain number in the Data Fault Status register. Similarly, on a prefetch abort, the MMU places an encoded four-bit value along with the four-bit encoded domain number in the Instruction Fault Status register. In addition, the MVA associated with the data abort is latched into the Fault Address

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NS9215 specifications

The Digi NS9215 is a powerful solution designed for industrial applications that require reliable connectivity and robust performance. Built on a foundation of advanced technologies, the NS9215 serves as a versatile networking device that meets the demands of automation, remote monitoring, and data acquisition.

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In conclusion, the Digi NS9215 is a robust networking device designed for a wide range of industrial applications. Its multi-protocol support, reliability, security features, user-friendly interface, and scalability make it a valuable addition to any industrial network infrastructure, delivering performance and efficiency that businesses can depend on for critical operations.

Digi NS9215 manual U Fault s a n d C P U a b o r t s

Models: NS9215

M M U f a u l t s a n d C P U a b o r t s

NS9215 specifications