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CoB Pad Frame and Precheck

CoB pad geometry, mapping, board compatibility, and golden-mask precheck.

This page owns CoB bond-pad geometry, pad mapping, slot-board compatibility, and the CoB-specific precheck.

Reference pad frame

The 1x1 reference described on 2025-10-09 has 74 pads: 54 signal pads and 20 power or ground pads. Signal-pad types may change. Pad positions and the power/ground arrangement should not change. Confirmed guidance by Leo Moser. (archive message; Discord)

The template workflow maps pads in config.yaml and instantiates them in chip_top.sv. Leo Moser warned that a different pad ring needs another wire-bonding setup. Confirmed guidance, 2025-10-27. (archive message; Discord)

Precheck history

  • 2026-06-03 — Confirmed release. Template 1.5.0 and precheck 1.6.0 added configurable SCL, PAD, and SRAM choices, the --cob check, and the parallel DRC runner. (archive message; Discord)
  • 2026-06-18 — Corrective action. Template 1.5.3 fixed a 0.5 µm north/south pad-position regression. Precheck 1.7.0 added a golden pad-mask check for CoB. Version 1.5.0 geometry is obsolete guidance where it conflicts with 1.5.3. (archive message; Discord)
  • 2026-07-10 — Run 2 guidance. The CoB setting changes precheck flags and verifies the expected pad layout. The deadline in the announcement is historical; the described check is durable. (archive message; Discord)
  • 2026-08-13 — Latest captured boundary. Manufacturing may accept any DRC-clean design, but CoB requires pads at the coordinates expected by the bonder. This is captured search evidence; its canonical Discord URL was not captured. (archive message)

Slot-board compatibility

The 1x0p5 board was reported power/ground compatible with 1x1. Pads 67 through 70 are reversed, so it is not fully signal-pin compatible. Confirmed design report, 2026-06-15. (archive message; Discord)

Proposal, 2026-05-24: Harmonizing all slot pinouts and avoiding half-slot die rotation were proposed, but the cited message does not show adoption. (archive message; Discord)

Conflict

BreakingTaps later said signal types can change and thought power pads might change, but marked that point uncertain. The earlier specific guidance says power/ground pads should not change. Use the fixed rule until the current golden mask supplies contrary evidence. (archive message; Discord) (archive message; Discord)

Sources

  • 1425749959227080724 — 2025-10-09T07:41:19.433Z — Leo Moser (mole99) — archive message; Discord — 74-pad reference and fixed geometry.
  • 1432270303668604948 — 2025-10-27T07:30:50.690Z — Leo Moser (mole99) — archive message; Discord — Pad mapping and bonding setup.
  • 1511722026648338514 — 2026-06-03T13:23:37.590Z — Leo Moser (mole99) — archive message; Discord — Template 1.5.0 and precheck 1.6.0.
  • 1508113764741025824 — 2026-05-24T14:25:40.913Z — RebelMike — archive message; Discord — Pinout-harmonization proposal.
  • 1516120547476373668 — 2026-06-15T16:41:46.676Z — RebelMike — archive message; Discord — Slot-board compatibility.
  • 1517130928248586290 — 2026-06-18T11:36:40.224Z — Leo Moser (mole99) — archive message; Discord — Pad regression fix and golden mask.
  • 1524956674861957282 — 2026-07-10T01:53:23.612Z — Tim 'mithro' Ansell — archive message; Discord — CoB precheck setting.
  • 1534312011234807838 — 2026-08-04T21:28:09.617Z — BreakingTaps — archive message; Discord — Uncertain power-pad opinion.
  • 1537441624102141982 — 2026-08-13T12:44:07.470Z — Leo Moser (mole99) — archive message — CoB coordinate boundary; canonical Discord URL not captured.