LED Blinker Circuit Design
DXF Drawing
MILLING_CUTOUT layer and shows the 1.5mm non-plated full-height isolation slot centered at x=85mm on the 200×140mm board. Specify 2-layer FR4, ENIG in the fab order notes.Table
| ERC Item | Design Decision | Why Accepted | Do Not Fix By |
|---|---|---|---|
| J_SIM:VPP | Leave unconnected | SIM VPP/programming voltage is unused on modern SIM cards; SIM1 power comes from U_LTE:USIM1_VDD to J_SIM:VCC. | Do not tie to 3.3V/4V/5V. |
| U_LTE:VDD_1V8 | Leave unconnected | Module auxiliary/reference 1.8V rail; not used by the board-level STM32 interface. Main LTE power is on U_LTE VBAT pins 55/56/57. | Do not back-feed external power. |
| U_LTE:VDD_2V8 | Leave unconnected | Module auxiliary/reference 2.8V rail; not required for the selected UART/SIM/RF interface. | Do not back-feed external power. |
| U_LTE:VBUS | Leave unconnected | USB interface is not used in this design; LTE control is via UART2. | Do not connect unless USB service port is intentionally added. |
| U_LTE:VBAT_ADC | Leave unconnected | Optional LTE ADC battery-sense input is unused; board already powers LTE from regulated VCC_4V_LTE. | Do not connect unless adding validated LTE voltage-sense divider. |
Status
Summary
Accepted ERC Power Warnings
Verified Main Connections
Layout Reminder