# ECP5 fabric-owned safety-gate record — 2026-08-28

## Result and scope

Company-authored physical-board engineering evidence: a volatile SRAM image on
the Lattice ECP5-5G Evaluation Board exercised a small fabric-owned gate. The
soft CPU submitted a narrow GPIO command, while the fabric—not CPU GPIO—owned
the eight onboard LED outputs. Read-only fabric status returned through GPIO
input and was retained over UART.

The final raw record reported:

```
safe=0
permit=1
timeout=2
invalid=4
pass=valid_permit,timeout_fail_closed,malformed_fail_closed,readback=ok
```

The gate required a fresh rising strobe, the next four-bit sequence number and
zero reserved bits. It removed permit after 480,000 fabric-clock cycles (40 ms
at the 12 MHz test clock) and failed closed on a malformed request. The image
was loaded over JTAG into volatile SRAM only; configuration flash, expansion
pins, product I/O and actuators were not touched.

## Scope

An LED-only prototype result in volatile SRAM on the ECP5 evaluation board.

## Reproducibility

The completed internal record is
`evidence/runs/2026-08-28-ecp5-fabric-safety-gate-001/manifest.json`. It
retains final source inputs, bitstream, build log, raw UART capture and hashes,
as well as the first status-encoding mismatch that was corrected before the
passing rerun.