Design Log DEC 104 user settings module role reworked as hid colour audio hub and jtag i2c spine - thepinkmile/Enigma-NG GitHub Wiki
DEC-104 - User Settings Module Reworked as HID Colour / Audio Hub and JTAG/I2C Spine
| Field | Value |
|---|---|
| Decision ID | DEC-104 |
| Status | Decided |
| Date | 2026-09-17 |
| Author | Izzyonstage & GitHub Copilot |
| Amends | DEC-032, DEC-034, DEC-051, DEC-071 |
| Related | DEC-103, DEC-105 |
Context
USM previously documented a switch-and-indicator role for CFG_ROUTE / CFG_REFMAP. The agreed
redesign repurposes the board into the shared HID lighting hub and the physical bridge between
Cypher, the HID pair, and Plugboard.
Decision
- USM becomes the shared HID colour / brightness hub.
- USM hosts the dedicated Cypher-peripherals I2C bus endpoint for the HID lighting path.
- USM hosts the relocated JTAG idle-termination network for the HID branch.
- USM reserves a placeholder-only audio position pending a later buzzer / speaker choice.
- USM no longer carries a user switch panel role.
Rationale
- Centralises the shared HID lighting and JTAG aggregation on the one board that physically touches Cypher, both HID boards, and Plugboard.
- Removes now-obsolete panel-control circuitry from the active design.
- Keeps the deferred audio decision attached to the correct physical board.
Impact
design/Electronics/User_Settings_Module/Design_Spec.mdandBoard_Layout.mdare rewritten.- Cypher, Cypher-Input, Cypher-Output, and Cypher-Plugboard documents now reference USM as the HID hub and JTAG / I2C spine.