PCB Self-Testing (PST)
Performed automatically by the firmware at power-on or when using the Serial Self-Test option.
These tests confirm both electrical connections and that the correct firmware is loaded for the LCC Fusion Card being assembled or installed.
Self-Testing by LCC Fusion Card
🔧 Self-Test Summary by Card
Focus: soldering/connectivity, devices installed, and use of test boads (Card Monitor Board for outputs; Card Button Board for inputs).
| Test Item | Node Card | Sound Card | Audio Card | BSD Card | UOD Card |
|---|---|---|---|---|---|
| Firmware–Hardware Match | X | X | X | X | |
| Serial Connections (Serial Console / WebSerial / BT) | X | X | X | X | |
| Power Input | Test and optinally report on OLED 12 VDC, 5 VDC, and 3.3 VDC, Low Voltage Alerts | 5V Power LED | 5V Power LED | 5V Power LED | 5V Power LED |
| Self-Test Summary Report | X | X | X | X | X |
| Incoming Command Validation | X | X | X | X | |
| I²C Device Scan / Connection Test | X | N/A | N/A | N/A | N/A |
| I²C Bus Test of Connections and Pull‑ups | Test to Node Bus Hub. | Test to Node Bus Hub and OLED (if present). | Test to Node Bus Hub. | Test to Node Bus Hub. | |
| UART Pins Connectivity | Tests RX (from DFPlayers, gentle) and TX (to DFPlayers, idle‑HIGH). | N/A | N/A | N/A | |
| Output Verification (open-circuit/short-circuit) | Test speakers by playing track 001 on SD | Test speakers by playing test tone | LEDs (on card or Card Monitor Board) | LEDs (on card or Card Monitor Board) | |
| Input Verification (open-circuit/short-circuit) | Test SD present and track 001.wav found | N/A | Occupancy / Shorts via Card Button Board | N/A | |
| Device / Module Detection | N/A | Test DFPlayer modules | N/A | N/A | Detects ultrasonic modules by trigger/echo response. |
| CAN Bus Test | X | N/A | N/A | N/A | N/A |
| Test Name | What This Checks | When Done | If There’s a Problem, Likely Causes | Things to Try / Fixes |
|---|---|---|---|---|
| Firmware–Hardware Match | Confirms the firmware matches the correct LCC Fusion Card by measuring a reference voltage on a specific MCU pin (each card has a unique resistor pair) | Card Installation | Wrong firmware loaded for this card, damaged resistor pair, or pin not soldered | Reload correct firmware for the card type; check resistor pair values; reflow pin on MCU or resistors |
| Serial Connections (Serial Console / WebSerial / BT) | Confirms the ESP32 starts correctly and serial connection is working | Card Installation | Wrong baud rate, missing data lines in USB cable, firmware not loaded | Use 115200 baud; try another cable or USB port; re-flash firmware |
| Power Input Check | Confirms that 12 VDC, 5 VDC, and 3.3 VDC lines are present and stable | Card Installation | Missing regulator, poor solder joint, short on a power line | Check voltages with a meter; reflow or replace suspect regulator; inspect for shorts |
| Open-Circuit Check | Uses internal pull-ups/downs to see if a GPIO responds to small “nudges,” confirming the pin isn’t floating or disconnected | Card Assembly or Installation | Unsoldered pin, broken trace, or poor joint | Reflow solder; check trace continuity; inspect under magnification |
| Short-Circuit Check | Detects if a GPIO is stuck high or low, suggesting it’s shorted to power or ground | Card Assembly or Installation | Solder bridge, reversed part, or shorted IC leg | Wick away solder bridge; clean and inspect area; re-seat IC |
| Drive / Readback Test | MCU drives a pin HIGH / LOW and reads back the change to confirm output works and trace is connected | Card Assembly or Installation | Wrong pin mode, open connection, or solder bridge | Verify correct pin number in code; inspect trace and solder |
| ESP32 → I2C Device Connection Test | MCU toggles its pin and verifies that the connected IC (e.g., ESP32 / MCP23017 / PCA9685) detects the change | Card Assembly or Installation | IC leg not soldered, wrong trace routing, or bad via | Reflow the IC leg; verify routing; clean pads and retest |
| Walking Pattern Check | Each GPIO is tested one by one to ensure there are no unintended links between pins | Card Assembly or Installation | Pins bridged by solder, wrong header, or duplicated trace | Inspect under magnifier; rework header or remove bridge |
| I²C Device Scan | Firmware checks that all connected I²C cards respond at their correct addresses | Card Installation | Address DIP switch incorrect, wiring open or reversed, missing pull-ups | Set proper address switch; recheck cable pinout; add or fix pull-ups |
| CAN Bus Test | Sends and receives a short test message on the CAN network to confirm wiring and transceiver function | Card Installation | Missing termination, reversed transceiver, CAN-H/L shorted | Check 120 Ω termination; verify transceiver orientation; inspect RJ45 pinout |
| Low-Voltage Alert | Detects supply voltage drop (brown-out) or weak power source | Card Installation | Underrated power adapter, poor solder joint, or short | Use stronger supply; reflow power connectors; check current draw |
| Self-Test Summary Report | Prints a summary of all pass/fail results to the Serial Monitor | Card Installation | One or more checks failed | Review the log for each failed line; fix the cause and rerun the test |
Tip: The self-test messages appear in the Serial Monitor window and can be saved to a text file for troubleshooting or support documentation.