AN 978: Nios® V Processor Migration Guidelines

ID 773196
Date 5/15/2024
Document Table of Contents

5.9. Error Correction Code

All Nios® V processor variant and Nios® II/f processors support ECC (except for Nios® II/e processor).
Table 33.  ECC Comparison
ECC Nios® V Processor Nios® II/f Processor
Supported variant
  • Nios® V/m
  • Nios® V/g
  • Nios® V/c
Nios® II/f
ECC Detection
  • 1-bit ECC error
  • 2-bit ECC error
  • 1-bit ECC error
  • 2-bit ECC error
ECC Recovery Available for instruction cache, or any 1-bit ECC errors.
Output Signals A conduit group, called cpu_ecc_status. An Avalon streaming source, called ecc_event_bus.
Status Reporting
  • cpu_ecc_status indicates the error status using 2-bit label encoding.
  • cpu_ecc_sourcecpu_ecc_source indicates the error source using 4-bit label encoding.

29-bit one-hot encoding representing:

  • Affected internal RAM blocks, and
  • Error type.