AP-1.8V Voltage Regulator Inquiry


Work done
  • Renamed the ESP32 module from ESP32-32E to U3 without altering any existing nets.
  • Wired the new labeled nets for the added subsystems:
    • Display U1: SPI_SCK, SPI_MOSI, DISP_CS, DISP_DC, DISP_RST, BL_PWM, plus power to Net 9 and GND.
    • GSR AFE U2: GSR_ADC to U3 SENSOR_VP (GPIO36), powered from Net 9 with local decoupling C14.
Final GPIO mapping
  • Display U1
    • SPI_SCK -> U3 IO18 (via series R88)
    • SPI_MOSI -> U3 IO23 (via series R89)
    • DISP_CS -> U3 IO16
    • DISP_DC -> U3 IO19
    • DISP_RST -> U3 IO14
    • BL_PWM -> U3 IO25
  • GSR
    • GSR_ADC -> U3 SENSOR_VP (GPIO36)
ERC summary
  • ERC still reports 1 error: "Missing Power" on display U1.
Blocker / why I cannot reach 0 ERC errors
  • The ERC engine flags U1 as missing power even though VCC is connected to Net 9 and GND is connected to GND.
  • I attempted a metadata-only fix (property edit) and also attempted to explicitly tie U1 to the regulator pins, but rewrite_connections cannot target AP-3.3V because its refdes contains a hyphen (tool restriction: refdes must be alphanumeric), so I cannot complete that workaround.
Next steps
  • If you allow it, I can rename AP-3.3V (and optionally AP-1.8V) to alphanumeric refdes (e.g., U4, U5) with no net changes, then explicitly connect U1 VCC/GND to the regulator pins and re-run ERC. Alternatively, we can replace the display symbol with one whose VCC pin is typed correctly (but that would destroy its nets and require re-wiring).

AP-3.3V
MAX
R89
Resistance
33Ω ohms
R90
Resistance
1MΩ ohms
R3
Resistance
10kΩ
R-SDA
Resistance
5.6kΩ
BOOT
R1
Resistance
10kΩ
C14
Capacitance
100nF
R6
Resistance
3.3kΩ
R10
Resistance
10kΩ
R4
Resistance
10kΩ
R9
Resistance
10kΩ
D-TTL
RESET
R5
Resistance
3.3kΩ
R-SCL
Resistance
5.6kΩ
R88
Resistance
33Ω ohms
R2
Resistance
10kΩ
U1
Battery
PWR
USB-TTL
CNT
LSM6
C4
Capacitance
22µF
C6
Capacitance
0.1µF
C3
Capacitance
1µF
C2
Capacitance
1µF
C8
Capacitance
10µF
C11
Capacitance
4.7µF
C5
Capacitance
0.1µF
C7
Capacitance
0.1µF
C12
Capacitance
100nF
C1
Capacitance
1µF
U3
AP-1.8V
C13
Capacitance
100nF
C10
Capacitance
0.1µF
C9
Capacitance
0.1µF
U2

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