SafeIsland Project Layout

Directory Structure

SafeIsland/
  rtl/                  Safety island RTL source files
    AXI/                Reusable AXI master/slave RTL
    safety_island_top.f Top-level RTL filelist, intended to run from rtl/
  tb/                   Testbench source files
    axi/                AXI unit testbenches and simulation-only models
  sim/
    modelsim/           ModelSim run scripts for top-level tests
      axi/              ModelSim run scripts for AXI unit tests
    vcs/                VCS/Verdi Linux replay templates
    out/                Generated simulation libraries, logs, WLF, VCD
  docs/                 Design notes, requirement check, simulation notes
  meeting/              Meeting and schedule notes

Main ModelSim Commands

Run from SafeIsland/sim/modelsim.

cd D:\studydoc\competition\PIC\SafeIsland\sim\modelsim
& 'D:\software\modelism\MODELISM\win64\vsim.exe' -c -do run_safety_island_top_basic_tb.do
& 'D:\software\modelism\MODELISM\win64\vsim.exe' -c -do run_safety_island_top_full_tb.do
& 'D:\software\modelism\MODELISM\win64\vsim.exe' -c -do run_safety_island_fault_injection_tb.do

Full-test waveforms are generated at:

SafeIsland/sim/out/safety_island_top_full/safety_island_top_full.wlf
SafeIsland/sim/out/safety_island_top_full/safety_island_top_full.vcd
SafeIsland/sim/out/safety_island_fault_injection/safety_island_fault_injection.wlf
SafeIsland/sim/out/safety_island_fault_injection/safety_island_fault_injection.vcd

Current full top regression covers 33+ cases, including AXI out-of-order, read interleaving, S_AXI write-verify, heartbeat self-check, KAT, and CRC-8/16 R-channel check tests.

The monitor AXI read interface includes m_axi_rcheck_flat, a parameterized CRC per master R beat (CRC_WIDTH=8 or 16). In CRC-8 mode the check covers {RID,RDATA,RRESP,RLAST} with polynomial 0x07 and initial value 0x00. In CRC-16 mode a two-stage E2E signature covers both AR-channel parameters and R-channel fields with polynomial 0x1021 and initial value 0xFFFF. A mismatch is reported as a bus fault.

Fault injection also writes the campaign summary to:

SafeIsland/sim/out/safety_island_fault_injection/fault_injection_summary.txt

The current engineering fault-injection campaign covers 21+ cases with undetected=0, including config shadow, core registers, bus faults, CRC E2E, TMR, and KAT.

Open WLF in ModelSim:

& 'D:\software\modelism\MODELISM\win64\vsim.exe' -view D:\studydoc\competition\PIC\SafeIsland\sim\out\safety_island_top_full\safety_island_top_full.wlf

AXI Unit Test Commands

Run from SafeIsland/sim/modelsim/axi.

& 'D:\software\modelism\MODELISM\win64\vsim.exe' -c -do run_axi_master_tb.do
& 'D:\software\modelism\MODELISM\win64\vsim.exe' -c -do run_axi_slave_tb.do

VCS/Verdi Templates

SafeIsland/sim/vcs/ contains Linux replay templates:

cd SafeIsland/sim/vcs
./run_top_full.sh
./run_fault_injection.sh

These scripts assume vcs/verdi and licenses are available from the shell environment. The locally verified flow for this workstation is still the ModelSim flow above.

ASIL-D Safety Enhancements (2026-06-25)

The following safety enhancements have been implemented to address AXI port interface fault detection gaps:

Enhancement	Files	Description
CRC-16 E2E Protection	safety_island_axi_read_engine.v, safety_island_top.v	Parameterized CRC_WIDTH (8/16), AR channel signature with two-stage CRC
Heartbeat Self-Check	safety_island_heartbeat.v	Periodic test injection to verify fault_detect output path integrity
Known-Answer Test (KAT)	safety_island_core_logic.v, safety_island_axi_config_slave.v	Pre-scan known-register read to validate complete read path
TMR Critical Paths	tmr_voter.v, safety_island_core_logic.v, safety_island_top.v	Triple-modular redundancy on FSM state, fault outputs, config lock
Write-Verify	safety_island_axi_config_slave.v	Post-write shadow consistency check for S_AXI write protection

Verification Summary

• Full TB regression: 33+ test cases
• Fault injection campaign: 21+ cases covering config shadow, core registers, bus faults, CRC E2E, TMR, KAT
• CRC_WIDTH=8 backward compatibility maintained