Design Log DEC 067 am sw1sw2 tactile switch rating accepted for production - thepinkmile/Enigma-NG GitHub Wiki
DEC-067 - AM SW1/SW2 Tactile Switch Rating Accepted for Production
| Field | Value |
|---|---|
| Decision ID | DEC-067 |
| Status | Confirmed |
| Date | 2026-05-12 |
| Author | Izzyonstage & Copilot |
| Amends | - |
Context
The Actuation Module carries two through-hole tactile switches adjacent to the UART service header (J5): SW1 (RESET_N) and SW2 (BOOT0), both specified as the Omron B3F-1070 (50 gf, rated 50,000 cycles). The purpose of these switches is to enter the STM32G071K8T3TR ROM bootloader for UART firmware loading - hold SW2 (BOOT0), press and release SW1 (RESET_N), then release SW2. This procedure is only needed at manufacturing time for initial firmware load and, rarely, during field maintenance if a firmware update is required and the primary SWD path (J4) is unavailable.
Decision
SW1 and SW2 shall remain as the Omron B3F-1070 (or equivalent SPST NO through-hole tactile switch) for production. No higher-rated or alternative switch type is required.
Rationale
The B3F-1070 is rated for 50,000 actuation cycles. Given that the buttons are used exclusively for manufacturing-time programming and occasional maintenance firmware updates - not by end users and not as part of normal operation - the expected lifetime actuation count is negligible relative to the rated cycle life. Longevity is not a concern. The existing part is appropriate and no change is warranted.
Files Changed
- None - no design change; decision documents a confirmed review outcome.