docs: Update unreleased changes in changelog and README

- Fixed USB hub controller (U401/CH334): XO pin connected to GND for crystal-less operation
- Fixed DC/DC converter (U202/XR76208): Enable circuit changed to Zener diode for 12V operation
- Fixed USB outputs: Replaced fuses with TPS2557 power distribution switches for backfeed protection
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2025-12-23 07:27:59 +01:00
parent 68937e160f
commit b883bc6c7d
17 changed files with 10132 additions and 8119 deletions

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@@ -9,6 +9,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/).
## [Unreleased]
### Fixed
- **USB Hub Controller (U401/CH334):** Pin 4 (XO) connected to GND to enable operation without crystal
- **DC/DC Converter (U202/XR76208):** Enable circuit changed from voltage divider to Zener diode to enable 12V operation
- **USB Outputs:** Fuses replaced with TPS2557 power distribution switches to prevent backfeeding
### Changed
- **Production:** Test points TP202/TP203 excluded from BOM
- **JLCPCB Optimization:** Rotation offsets adjusted for automated assembly
@@ -16,6 +21,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/).
- U401: FT Rotation Offset 180°
### Technical Details
- **USB Hub Stability:** CH334 now operates in internal oscillator mode without external crystal
- **Extended Input Voltage:** XR76208 now supports 12-24V input voltage through Zener diode-based enable circuit
- **USB Backfeed Protection:** TPS2557 prevents backfeeding from external USB devices and provides overcurrent/short-circuit protection
- **Manufacturing Efficiency:** Optimized component orientation reduces production time
## [Rev. 0.3] - 2025-12-09