PCB Design Revision
Run ERC/DRC and list any remaining schematic issues.
Thought for 9 sec
I’ll rerun both schematic/ERC and PCB/DRC checks now, then list only remaining schematic-side issues separately from layout results.
Thought for 4 sec
I’m blocked from running the requested ERC/DRC because the session has run out of execution credits.
Current known state from the last completed checks:
- PCB/layout DRC was previously clean after routing cleanup.
- The earlier missing-power ERC errors on J4:VCC and MEGA1:VIN were cleared after adding VCC and VIN power-source markers.
- One known schematic warning remained: Floating pin: PWR_VCC:P1 on the power marker terminal. This appears to be a marker-symbol warning, not a functional rail issue.
What remains:
- Re-run ERC and DRC fresh when credits are available.
- Confirm whether PWR_VCC:P1 is still the only schematic warning.
- If desired, replace/adjust the marker implementation so the power-source marker itself does not create a floating-pin warning.
Fix PWR_VCC warning
Inspect power markers
Document review status
Re-run later
Refine this doc
Ask about this doc
Board Bring-Up Plan — Mini Paper USV PCB Upgrade v1.0
Prerequisites
- Multimeter, bench supply/current-limited battery adapter, oscilloscope if available.
- Arduino Mega 2560 USB cable and firmware from the Firmware Starter project file.
- Do not install the motor or servo for first power-on current checks.
1. Visual Inspection
- Confirm U1 L293D orientation.
- Confirm J3 battery polarity: pin 1 = 9V, pin 2 = GND.
- Confirm R1, R2, R3 are 220 ohm.
- Inspect LED orientation: anodes to resistors, cathodes to GND.
2. Power Rail Verification
Table
| Rail | Source | Expected Voltage | Measure At | Current Limit | Pass Criteria |
|---|---|---|---|---|---|
| 9V | J3 dual battery input | 7-12V acceptable for MEGA VIN; 9V nominal | J3 pin 1 to GND | 200mA initial without motor/servo | No short, stable input |
| 5V | MEGA onboard regulator / 5V rail | 5.0V | U1 VCC1, J4 VCC, J5 pin 2 | 200mA initial without motor/servo | 4.75-5.25V |
| GND | J3 pin 2 | 0V reference | all GND pins | n/a | continuity to MEGA GND |
3. Critical Signal Verification
Table
| Signal | Net | Expected State / Test |
|---|---|---|
| Motor enable | ENA | PWM on D9 when motor commanded |
| Motor direction | IN1 / IN2 | complementary logic on D8/D7 |
| Ultrasonic trigger | TRIG | 10us pulse on D11 |
| Ultrasonic echo | ECHO | TTL pulse width proportional to distance on D12 |
| Servo signal | SERVO_SIG | 50Hz servo pulse on D6 |
| LEDs | GL1/YL1/RL1 | GPIO-driven 5V logic through 220 ohm resistors |
| Buzzer | BUZ | D28 toggles or tone output |
4. Connector and Interface Tests
Table
| Connector | Pins to Verify | Test Method |
|---|---|---|
| J3 battery input | 1=9V, 2=GND | polarity and voltage check before connecting board |
| J4 HC-SR04 | VCC/TRIG/ECHO/GND | verify 5V and firmware distance reading |
| J5 servo | 1=SIG, 2=5V, 3=GND | verify pulse before plugging servo |
| J6 motor | Pin_1/Pin_2 | verify motor voltage with PWM command |
| J7 buzzer | +=BUZ, -=GND | run tone test |
| J8/J9/J10 LEDs | anode via resistor, cathode GND | blink test |
5. Programming
- Connect the MEGA 2560 USB cable.
- Select Arduino Mega 2560 / ATmega2560.
- Upload the firmware starter sketch.
- Open serial monitor at 115200 baud.
- Verify distance readings appear.
6. Functional Validation
Table
| Test | Components | Expected Output |
|---|---|---|
| LED test | R1-R3, J8-J10 | each LED lights under firmware control |
| Ultrasonic test | J4 | distance updates when object moves |
| Servo test | J5 | rudder servo moves to commanded angles |
| Motor test | U1, J6 | motor spins with direction and speed control |
| Buzzer test | J7 | audible tone when obstacle threshold is met |
7. Pass/Fail Summary
Table
| Section | Result | Notes |
|---|---|---|
| Visual inspection | [ ] Pass / [ ] Fail | |
| Power rails | [ ] Pass / [ ] Fail | |
| Programming | [ ] Pass / [ ] Fail | |
| Sensor | [ ] Pass / [ ] Fail | |
| Actuators | [ ] Pass / [ ] Fail | |
| Indicators | [ ] Pass / [ ] Fail |
Design Risk to Check
If the servo causes the 5V rail to sag or the MEGA regulator becomes hot, add a dedicated 5V regulator for servo/peripheral power before PCB fabrication.
Prerequisites
1. Visual Inspection
2. Power Rail Verification
3. Critical Signal Verification
4. Connector and Interface Tests
5. Programming
6. Functional Validation
7. Pass/Fail Summary
Design Risk to Check
