Nios® V Processor: Lockstep Implementation User Guide

ID 833274
Date 4/17/2025
Public

Visible to Intel only — GUID: jir1725868690849

Ixiasoft

Document Table of Contents

2.2.2.1. Transitioning between System States

One-hot encodings of the fRSmartComp state:
  • 0x01—DISABLED.
  • 0x02—OD
  • 0x04—FCS
  • Others—Reserved/Unused
Table 5.  Supported Actions for System States (Executed by System Supervisor)
Configuring System States Action
Read the current system Reads the ERRCTRL_FNPERIPHGI4[7:0] register.
Enter the DISABLED state Writes the ERRCTRL_ENABLE_KEY register with the DISABLE key (0xABCDABCD).
Enter the OD state from the DISABLED state Writes the ERRCTRL_ENABLE_KEY register with the ENABLE key (0x75601522).
The DISABLED state behavior:
  • Provides a standard DCLS configuration in which the fRSmartComp’s diagnostic functionalities are active.
    • The comparator is active unless the DISABLED state has been reached after a comparator mismatch. In such a case, it is not active.
    • The Timeout, the Counters, and the Latent fault safety mechanisms are active.
  • In this state, the fRSmartComp does not take most failure control actions in DISABLED state. In particular:
    • If any alarm is generated, the system maintains the DISABLED state and does not activate a Timeout for restoration.
    • If a Comparator enters self-detection, it generates the ALARM2, but it does not activate the dedicated logic to identify the fault position (third comparison).
    • The automatic reset request after a Comparator mismatch is not generated, despite being enabled.