Cypher-Output Board - 26-Character Variant Design Specification

Status: Draft Project: Enigma-NG Version: v.0.1.0 Associated Hardware Revision: Rev A Last Updated: 2026-08-16 Parent Document: design/Electronics/Cypher-Output/Design_Spec.md

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1. Overview

This document specifies the 26-Char Classic variant of the Enigma-NG Cypher-Output Board. It mirrors the 26-Char Classic Cypher-Input Board's QWERTZ layout, 1:1: 26 lens positions, one per letter, with no positions for Shift, Space, or Enter (matching the paired keyboard's own lack of those keys). This is the simplest Cypher-Output variant.

All three Cypher-Output variants (26-Char Classic, 64-Character, 10-Numeric) share an identical circuit topology (ENC module mount, per-position LED indicator bank, Cypher Board interconnect, board-identification strap) - see design/Electronics/Cypher-Output/Design_Spec.md. Only lens count/layout, plain-bits allocation, and BOARD_ROLE_ID_OUT value differ between variants.

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2. Lens Layout

• Layout: QWERTZ, 26 lens positions (A-Z), mirroring the 26-Char Classic Cypher-Input keyboard layout 1:1 - see Cypher-Input/Cypher_Input_26_Char_Design.md §2.
• Lens count: 26.
• Non-cipher positions: None (no Space or Enter lens on this variant, matching the paired keyboard).

The physical lens arrangement mirrors the same three-row QWERTZ layout (9 + 8 + 9 positions) as the paired 26-Char Classic keyboard, per Mechanical/Lightboard_Assembly/Design_Spec.md §2:

  Q   W   E   R   T   Z   U   I   O
    A   S   D   F   G   H   J   K
  P   Y   X   C   V   B   N   M   L

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3. plain-bits Allocation

Range	Assignment
PB[0:25]	26 lens-position select outputs, QWERTZ layout, position-for-position matching Cypher-Input's own 26-Char Classic plain-bits allocation
PB[26:63]	Unused - spare plain-bit positions

Provisional pending Quartus pin-planning and PCB layout on the ENC module side. See Design_Spec.md §3 for the common ENC module interface and full J4 zig-zag pin map (Board_Layout.md §1). LED colour and illumination are received entirely from the User Settings Module and never use any plain-bits position - see Design_Spec.md §1.

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4. Board Identification

• BOARD_ROLE_ID_OUT[3:0] strap value: 0b0001 (Characters only; fixed, no switch; see Cypher/Board_Layout.md §4 encoding table).

This variant has no custom-support switch - only the 64-Character variant carries one (see Cypher_Output_64_Char_Design.md §4).

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5. Bill of Materials (26-Char Variant-Specific Components)

Variant-specific components for the 26-Char Classic variant. Common components shared across all Cypher-Output variants are listed in design/Electronics/Cypher-Output/Design_Spec.md §11.

RefDes	Specification	MPN	Manufacturer	DigiKey PN	Mouser PN	JLCPCB PN	Alt Supplier + PN	Notes	Footprint Available	Footprint Downloaded	Qty
D1-D26	RGB SMD LED (placeholder - MPN TBD, same part as Cypher-Input, pending confirmation)	TBD	TBD	-	-	-	-	One per lens position; colour/illumination received entirely from the User Settings Module (no local generation); top face - not populated in PCBA, hand-soldered by the user after delivery (see Design_Spec.md §2 Architecture)	-	-	26
R1-R26 (Red)	0402, value TBD pending LED part confirmation	TBD	TBD	-	-	-	-	Red channel current-limit	-	-	26
R1-R26 (Green)	0402, value TBD pending LED part confirmation	TBD	TBD	-	-	-	-	Green channel current-limit	-	-	26
R1-R26 (Blue)	0402, value TBD pending LED part confirmation	TBD	TBD	-	-	-	-	Blue channel current-limit	-	-	26
Q1-Q26	N-channel MOSFET, SOT-23	2N7002K	onsemi (or equiv.)	-	-	-	-	Per-position LED select, gated by that position's decoded plain-bits line; see Design_Spec.md §4	✔	-	26