docs: MMCM places but is dead on silicon -> open-flow structural options exhausted (Refs #1764)

[gHashTag]

Tests the last structural lever for the seed-lottery and closes the open-toolchain path.

Regenerate the 200 MHz clock through the MMCM/CMT tree (low-skew) instead of the fabric IBUFDS net, to probe the global clock-skew hypothesis. MMCME2_BASE places in nextpnr and the fasm builds, but the flashed bitstream is dead on the AX7203 — no UART response on any of four seeds, with or without a BUFG on the MMCM output. The open flow (prjxray fasm2frames) does not emit the MMCM configuration bits, so the MMCM never locks / drives no clock.

So the MMCM lever is placement-only on openXC7, not functional — the clock-skew hypothesis cannot be tested here, and the open-toolchain structural options are fully exhausted (11 local fixes ruled out + MMCM dead). Only commercial P&R (Vivado) can close timing directly or provide a working MMCM. Seed-search is the final practical answer on the open flow. Added ruled-out item #12.

Board restored to the generated capstone (XOR 4/4). Docs-only. Refs #1764

[github-actions]

📓 NotebookLM Notebook linked to this PR

• Notebook ID: b83263109fb055dc
• URL: https://notebooklm.google.com/notebook/b83263109fb055dc

This notebook contains session context, decisions, and artifacts for this work.

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PR Dashboard

Generated at: 2026-08-08 02:56:12 UTC

• docs: MMCM places but is dead on silicon -> open-flow structural options exhausted (Refs #1764) #1907 docs: MMCM places but is dead on silicon -> open-flow structural options exhausted (Refs #1764) | Created: 2026-08-08 | Updated: 2026-08-08 | 10 failing / 15 total
• feat(igla): Wave Loop 898 — module-scope [615][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes #1900 feat(igla): Wave Loop 898 — module-scope [615][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes | Created: 2026-08-07 | Updated: 2026-08-07 | 1 failing / 3 total
• chore: civilian mesh positioning — drop drone wording (bpsk.t27) #1874 chore: civilian mesh positioning — drop drone wording (bpsk.t27) | Created: 2026-08-07 | Updated: 2026-08-07 | 2 failing / 25 total
• feat(igla): Wave Loop 897 — module-scope [613][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes #1858 feat(igla): Wave Loop 897 — module-scope [613][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes | Created: 2026-08-07 | Updated: 2026-08-07 | 1 failing / 3 total
• feat(igla): Wave Loop 896 — module-scope [611][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes #1856 feat(igla): Wave Loop 896 — module-scope [611][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes | Created: 2026-08-07 | Updated: 2026-08-07 | 1 failing / 3 total
• feat(igla): Wave Loop 895 — module-scope [609][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes #1854 feat(igla): Wave Loop 895 — module-scope [609][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes | Created: 2026-08-07 | Updated: 2026-08-07 | 1 failing / 3 total
• feat(igla): Wave Loop 894 — module-scope [607][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes #1852 feat(igla): Wave Loop 894 — module-scope [607][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes | Created: 2026-08-07 | Updated: 2026-08-07 | 1 failing / 3 total
• feat(igla): Wave Loop 893 — module-scope [605][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes #1850 feat(igla): Wave Loop 893 — module-scope [605][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes | Created: 2026-08-07 | Updated: 2026-08-07 | 1 failing / 3 total
• feat(igla): Wave Loop 892 — module-scope [603][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes #1847 feat(igla): Wave Loop 892 — module-scope [603][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes | Created: 2026-08-07 | Updated: 2026-08-07 | 1 failing / 3 total
• feat(igla): Wave Loop 891 — module-scope [601][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes #1844 feat(igla): Wave Loop 891 — module-scope [601][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes | Created: 2026-08-07 | Updated: 2026-08-07 | 0 failing / 4 total
• feat(igla): Wave Loop 890 — module-scope [599][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes #1842 feat(igla): Wave Loop 890 — module-scope [599][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes | Created: 2026-08-07 | Updated: 2026-08-07 | 0 failing / 4 total
• feat(igla): Wave Loop 883 — module-scope [585][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes #1815 feat(igla): Wave Loop 883 — module-scope [585][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes | Created: 2026-08-06 | Updated: 2026-08-06 | 0 failing / 1 total
• feat(igla): Wave Loop 882 — module-scope [583][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes #1813 feat(igla): Wave Loop 882 — module-scope [583][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes | Created: 2026-08-06 | Updated: 2026-08-06 | 0 failing / 12 total
• feat(igla): Wave Loop 881 — module-scope [581][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes #1810 feat(igla): Wave Loop 881 — module-scope [581][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes | Created: 2026-08-06 | Updated: 2026-08-06 | 0 failing / 12 total

Summary

Status	Count
Total Open PRs	14
PRs with Failing Checks	1
PRs with All Checks Green	13
READY	5
FAILING	1
PENDING	0

Seal Status

• ⚠️ STALE -- sha256(compiler.rs)=2bd87d0d139e != manifest seal=87e5cbd3ad94.
  The committed NMSE numbers were certified against an older compiler.rs.
  Run scripts/reseal-check.sh locally for the two-step reseal command (advisory; not a merge gate).

[github-actions]

📓 NotebookLM Notebook linked to this PR

• Notebook ID: b83263109fb055dc
• URL: https://notebooklm.google.com/notebook/b83263109fb055dc

This notebook contains session context, decisions, and artifacts for this work.

[github-actions]

PR Dashboard

Generated at: 2026-08-08 02:56:52 UTC

• docs: MMCM places but is dead on silicon -> open-flow structural options exhausted (Refs #1764) #1907 docs: MMCM places but is dead on silicon -> open-flow structural options exhausted (Refs #1764) | Created: 2026-08-08 | Updated: 2026-08-08 | 10 failing / 15 total
• feat(igla): Wave Loop 898 — module-scope [615][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes #1900 feat(igla): Wave Loop 898 — module-scope [615][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes | Created: 2026-08-07 | Updated: 2026-08-07 | 1 failing / 3 total
• chore: civilian mesh positioning — drop drone wording (bpsk.t27) #1874 chore: civilian mesh positioning — drop drone wording (bpsk.t27) | Created: 2026-08-07 | Updated: 2026-08-07 | 2 failing / 25 total
• feat(igla): Wave Loop 897 — module-scope [613][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes #1858 feat(igla): Wave Loop 897 — module-scope [613][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes | Created: 2026-08-07 | Updated: 2026-08-07 | 1 failing / 3 total
• feat(igla): Wave Loop 896 — module-scope [611][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes #1856 feat(igla): Wave Loop 896 — module-scope [611][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes | Created: 2026-08-07 | Updated: 2026-08-07 | 1 failing / 3 total
• feat(igla): Wave Loop 895 — module-scope [609][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes #1854 feat(igla): Wave Loop 895 — module-scope [609][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes | Created: 2026-08-07 | Updated: 2026-08-07 | 1 failing / 3 total
• feat(igla): Wave Loop 894 — module-scope [607][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes #1852 feat(igla): Wave Loop 894 — module-scope [607][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes | Created: 2026-08-07 | Updated: 2026-08-07 | 1 failing / 3 total
• feat(igla): Wave Loop 893 — module-scope [605][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes #1850 feat(igla): Wave Loop 893 — module-scope [605][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes | Created: 2026-08-07 | Updated: 2026-08-07 | 1 failing / 3 total
• feat(igla): Wave Loop 892 — module-scope [603][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes #1847 feat(igla): Wave Loop 892 — module-scope [603][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes | Created: 2026-08-07 | Updated: 2026-08-07 | 1 failing / 3 total
• feat(igla): Wave Loop 891 — module-scope [601][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes #1844 feat(igla): Wave Loop 891 — module-scope [601][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes | Created: 2026-08-07 | Updated: 2026-08-07 | 0 failing / 4 total
• feat(igla): Wave Loop 890 — module-scope [599][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes #1842 feat(igla): Wave Loop 890 — module-scope [599][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes | Created: 2026-08-07 | Updated: 2026-08-07 | 0 failing / 4 total
• feat(igla): Wave Loop 883 — module-scope [585][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes #1815 feat(igla): Wave Loop 883 — module-scope [585][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes | Created: 2026-08-06 | Updated: 2026-08-06 | 0 failing / 1 total
• feat(igla): Wave Loop 882 — module-scope [583][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes #1813 feat(igla): Wave Loop 882 — module-scope [583][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes | Created: 2026-08-06 | Updated: 2026-08-06 | 0 failing / 12 total
• feat(igla): Wave Loop 881 — module-scope [581][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes #1810 feat(igla): Wave Loop 881 — module-scope [581][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes | Created: 2026-08-06 | Updated: 2026-08-06 | 0 failing / 12 total

Summary

Status	Count
Total Open PRs	14
PRs with Failing Checks	1
PRs with All Checks Green	13
READY	5
FAILING	1
PENDING	0

Seal Status

• ⚠️ STALE -- sha256(compiler.rs)=2bd87d0d139e != manifest seal=87e5cbd3ad94.
  The committed NMSE numbers were certified against an older compiler.rs.
  Run scripts/reseal-check.sh locally for the two-step reseal command (advisory; not a merge gate).