Design Log DEC 084 cypher stack architecture migration and board role consolidation - thepinkmile/Enigma-NG GitHub Wiki

DEC-084 - Cypher-Stack Architecture Migration and Board-Role Consolidation

Field Value
Decision ID DEC-084
Status Confirmed
Date 2026-07-04
Author Izzyonstage & GitHub Copilot
Supersedes Architectural ownership model of standalone Stator/Reflector/Extension/JTAG Module/Actuation Module in active topology

Context

The merged extension-mechanical architecture discussions define a new active board topology centered on Cypher Board + mini-stack boards, with clear migration away from several legacy standalone board roles. The design now requires one consolidated decision entry to anchor this migration in the main design set.

Decision

Adopt the cypher-stack merged architecture as the active migration baseline:

  1. Cypher Board becomes the central cipher backplane and replaces standalone Stator + Reflector ownership in the active architecture.
  2. Stack-Input and Stack-Output replace standalone Extension ownership for mini-stack ingress/egress.
  3. Stack-Blanking is the passive end-of-chain routed termination board.
  4. Input-Cypher and Output-Cypher are the active user-facing cypher-side boards.
  5. Standalone JTAG Module and standalone Actuation Module ownership migrate into the new active board set (Cypher and Stack-Input respectively).

Rationale

The merged topology is mechanically and electrically consistent with the current discussion outcomes, reduces split ownership across legacy boundaries, and provides a clean architecture baseline for applying the merged discussions into the main design before final component/BOM lock.

Impact

  1. Main architecture docs are updated to use the merged board set and migration ownership model.
  2. New board-level design specs are created for:
    • Cypher_Board
    • Stack_Input_Board
    • Stack_Output_Board
    • Stack_Blanking_Board
    • Input_Cypher_Board
    • Output_Cypher_Board
  3. Legacy standalone board documents are retired from active paths and moved to .recycle-bin with path-preserving structure for traceability.
  4. Procurement-detail lock remains deferred to post-merge final design/BOM sweep.