Nios® V Processor: Lockstep Implementation User Guide

ID 833274
Date 4/17/2025
Public

Visible to Intel only — GUID: akq1724947516273

Ixiasoft

Document Table of Contents

1.1. Nios® V Processor Lockstep Features

The Nios® V processor Lockstep mainly comprises the features listed in the following table.
Table 2.  Lockstep Features and Description
Feature Description
Self-checking Comparator
  • Self-diagnostic logic preventing false detection.
  • Fine grain comparator to accommodate Nios® V processor configurations at minimum resource usage.
  • Programmable blind window to temporarily disable the comparator after reset.
Common Cause Failure Countermeasure Time diversity by means of timing skew between the two Nios® V processor instances.
Programmable Timers and Counters
  • Programmable RESET and ENABLE events counter to detect never-ending system loops due to wrong software execution.
  • Programmable timeout to flag deadlocks at system level during or after the boot.
Error Controller Interface
  • User interface to read the Alarm signal status.
  • Flags error detection to the system supervisor.
  • Programmable alarm severity to meet the applications needs.
  • Programmable decisions and actions in the event of errors.
Configuration and Status Interface
  • User interface to read status and configure fRSmartComp.
  • Logs and alarm context information generated for each safety mechanism to enable fine-grain failure control techniques.
  • Configuration registers containing safety-related information protected against faults.
Built-in Hardware Fault Injector Dummy faults injection facilities to ease chip-level hardware and software integration tests
Supported processor Nios® V/g processor
Figure 2. Microarchitecture of Lockstep DCLS ArchitectureThis figure shows a conceptual view of the key features of the Lockstep DCLS architecture but does not represent the IP microarchitecture.
The fRSmartComp solution contains these interfaces:
  • Configuration interface— Avalon® memory-mapped interface to configure and control the fRSmartComp solution.
  • System interface—conduit representing the Lockstep alarm, reset, and mode signals.
  • Extended Reset interface—reset interface for Extended Reset Control.