owr_dl: Verification Report

1. Test results

Run on 2026-10-06 with GHDL 6.0.0 (mcode), VUnit 5.0.0.dev7, UVVM 2026.03.20: python run.py "*owr_dl*".

Testbench	Tests	Passed
owr_dl_tb	19	19

2. Summary

All 19 test cases pass; every requirement of the specification is covered (see the verification plan). VSG reports no errors and no warnings.

Measured values:

Item	Value
ErrorReset, ErrorWait, Started and Connecting timers	6.4 us and 12.8 us within the ranges of ECSS 5.5.7.1c, d
FCTs sent in Connecting with a receive FIFO of 64	7
User data throughput at 100 Mb/s, packets of 1000 bytes	79.96 Mb/s (99.9 % of the 80 Mb/s of 10-bit data characters)

Findings:

Finding	Resolution
The receive credit counter overflowed its range in a delta cycle of the simulation (stale FCT-sent event with the new credit)	Increment limited to 56; FCTs are only requested up to 48, so the limit never acts in a clock cycle
After a parity error the last data character before the error is not passed	Correct: its data bits are covered by the failing parity bit (ECSS 5.4.3.4b); the receiver passes only confirmed characters, the EEP follows the confirmed ones

Observations:

• An FCT, N-Char or broadcast code received in Started cannot be produced from the line: Started is entered with gotNull either not yet asserted (then no character is decoded) or asserted (then the port moves to Connecting two cycles later, after its first Null). The exit is implemented as specified.
• The reserved place for the EEP of a recovery is always free with the FCT rule of DL-4 (section 3 of the architecture), so the wait for room of ECSS 5.5.8.4a.4 is implemented but not reachable with a FIFO of 64.