0hmX/am3352-ddr-track-a-local-dfm-wip-20261007

docs/routing-244-checkpoint.md

# Routing checkpoint: 244 of 251 nets

DDR BA2 now has zero uncovered trace body and a measured 0.0109 mm margin on both Inner1 and Inner3. A straight/45-degree CPU escape and slight reductions to four existing tuning banks preserve its 41.070761 mm length, Inner2 routing, 0.100 mm width and two centered endpoint vias. No plane, hole, placement or other trace changes occur. Physical copper and finished-hole gaps are 0.1875 and 0.2625 mm. No new spacing or plane exception is required.

The preceding D1 and A10 repairs, reviewed support placements and exact 33-ohm channel mappings remain. Since the initial 240-net snapshot, HDMI_D2, HDMI_D17, HDMI_D5 and HDMI_D20 are complete. The processor and RAM stay fixed.

Direct production native bytes match the independently validated candidate. Native regression exits 0 against f5bcf91; actual Gerber/Excellon checks retain 244 nets with zero shorts or missing pin/barrel/drill copper. Fresh whole-board post-drill comparison finds no new reference gaps. All emitted reference copper and 1187 actual holes are unchanged, preserving the proven connected group of 393 ground terminals. All 46 DDR route lengths/layers/widths and 68 centered signal vias are retained; no route has more than two. Official trace lint reports zero issues. Twenty-three inherited projected warnings remain visible and do not establish manufacturing feasibility.

DDR reference-area findings decrease from 11 to 10; additional zero/low margins remain open. Seven nets remain: HDMI_D0/D8/D11/D15 and SYSBOOT2/6/10. Three signal midpoints, nine off-pad power joins, two connector overhangs and 15 missing-courtyard warnings remain. RAM supply barrel dependencies, RGB timing, active pull stubs and source termination remain unqualified. Unaccepted SYSBOOT6/SYSBOOT10 studies are excluded.

Runtime/source bytes match accepted local checkpoint `3278cc54eb9747336d3907b282f8525856c136e5`; publication uses separate commit lineage. Native SHA256: `a67ba602cd5ad28a9b3adc3e96f0171671f41f2fe9bcec1c5da660e025f42c4d`. See the [validation summary](routing-244-validation.json). Keep this PR draft: no fabrication, boot, timing, SI/PI or ampacity signoff.