NMEA 2000 iPad Adapter
Worked for 9 mins 45 sec
Paused because the account is out of ACUs again, so I can’t continue routing or DRC/DFx cleanup.
Accomplished:
- Placed the 90 × 80 mm prototype board with USB/ESP on the left, isolated CAN/NMEA on the right, J1/J2 at board edges, and ESP32 antenna at the top edge.
- Applied a 4-layer routing setup and successfully completed one autoroute pass.
- Found the remaining DRC blocker at the USB ESD array ground, then repositioned/rotated D2 for a cleaner GND escape.
- Cleared stale routing so the board is ready for a fresh reroute.
Open items:
- Fresh autoroute is not complete; the run paused due to no ACUs.
- Current board will show expected airwires because routing was intentionally cleared before the fresh route.
- Need re-check the router’s reported placement anomaly after ACUs are available.
- Full DRC/DFx pass is still pending.
- Generic passives still need production MPNs.
Suggested next steps:
- Refill ACUs.
- Resume or restart autoroute from the current clean preflight state.
- Run full DRC and fix remaining routing/layout issues.
- Run DFx/manufacturing review and assign passive MPNs.
Resume autorouting
Inspect placement anomaly
Assign passive MPNs
Run DRC and DFx
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Board Bring-Up Plan — NMEA 2000 WiFi Listener
Prerequisites
- Bench USB 5 V supply or USB-C host capable of at least 700 mA.
- Multimeter, oscilloscope, USB serial monitor, and a bench CAN/NMEA 2000 test source.
- Use the Firmware Starter project file for initial firmware.
- Do not connect to a real vessel backbone until isolation, grounds, and listen-only behavior are verified on the bench.
1. Visual Inspection
- Confirm
U1ESP32-S3-MINI-1 orientation and antenna end. - Confirm
U2ISO1050,U3AP2112K,U4ISU0205S05,D1CAN ESD,D2USB ESD, andL1CMC orientation. - Confirm there is no fitted 120 ohm CAN termination in Rev A.
- Confirm no solder bridge crosses the USB/ESP ground domain to the isolated
ISO_GND/NET-C domain.
2. Power Rail Verification
Table
| Rail | Source | Expected | Measure at | Current limit | Pass criteria |
|---|---|---|---|---|---|
USB_5V | USB-C J1 VBUS | 5.0 V | J1:VBUS, U3:VIN, U4:+VIN | 700 mA | 4.75-5.25 V |
3V3 | U3 AP2112K-3.3 | 3.3 V | U3:VOUT, U1:3V3, U2:VCC1 | 600 mA | 3.20-3.40 V; no ESP32 brownout during Wi-Fi |
ISO_5V | U4 isolated DC/DC | 5.0 V isolated | U4:+VOUT, U2:VCC2 | 100 mA | 4.75-5.25 V relative to ISO_GND |
GND | USB side | 0 V ref | USB shell/GND, U2:GND1 | n/a | Not shorted to ISO_GND except through intended isolation capacitance |
ISO_GND | Isolated CAN side / NET-C | isolated ref | U4:-VOUT, U2:GND2, J2:3.x | n/a | Isolated from USB GND by resistance check |
Procedure:
- With power off, measure resistance between
USB_5VandGND,3V3andGND,ISO_5VandISO_GND, andGNDtoISO_GND. - Power from USB with current limit.
- Verify
USB_5V, then3V3, thenISO_5V. - During Wi-Fi AP operation, check
3V3droop and AP2112K temperature.
3. Critical Signal Verification
Table
| Signal | Expected state | Measure at | Notes |
|---|---|---|---|
ESP_EN | High after power-up | U1:EN | Pull-up R3, reset button S1 pulls low |
ESP_BOOT | High normally | U1:IO0 | Pull-up R4, boot button S2 pulls low |
CAN_TXD_RECESSIVE | High/recessive | U2:TXD, R5:P2 | Primary hardware listen-only check |
CAN_RXD | Toggles on received frames | U2:RXD, U1:IO18 | Logic-side receive only |
CAN_H/CAN_L | CAN differential waveform | U2, L1, J2 side | Use bench CAN source first |
4. Connector and Interface Tests
Table
| Connector | Pins to verify | Test method |
|---|---|---|
J1 USB-C | VBUS, GND, CC1/CC2, D+/D- | USB enumeration, 5 V present, firmware upload |
J2 NMEA prototype terminal | Shield, NET-C/ISO_GND, CAN_H, CAN_L | Continuity to ISO_GND, D1, L1, U2; verify field pinout before boat use |
5. Programming and Debug
- Flash the Firmware Starter using PlatformIO.
- Confirm serial output announces TWAI listen-only mode.
- Join iPad to AP
N2K-Listenerand openhttp://192.168.4.1/. - Confirm the web page updates the raw frame counter when bench CAN/NMEA 2000 traffic is present.
6. Functional Validation
Table
| Test | Input | Expected output | Pass criteria |
|---|---|---|---|
| USB programming | USB-C to host | ESP32-S3 enumerates/flashes | Firmware uploads reliably |
| Wi-Fi dashboard | iPad joins AP | Web page loads | /api/frame returns JSON |
| CAN receive | 250 kbit/s extended CAN frames | RX counter increments | PGN/source fields decode from 29-bit ID |
| Listen-only safety | Monitor CAN_TXD_RECESSIVE | Stays high | No dominant TXD pulses during reset, boot, Wi-Fi, or receive |
| Isolation sanity | DMM between GND and ISO_GND | No DC short | Domains remain separated |
7. Open Bring-Up Risks
- AP2112K thermal margin must be tested under sustained Wi-Fi AP load; switch to a buck regulator if it overheats or browns out.
J2is a prototype terminal connector; final NMEA 2000 field connector/pinout must be confirmed before layout freeze.- Shield handling is prototype-defined; do not bond NMEA shield to USB ground in Rev A.
Pass/Fail Summary
Table
| Section | Result | Notes |
|---|---|---|
| Visual inspection | [ ] Pass / [ ] Fail | |
| Power rails | [ ] Pass / [ ] Fail | |
| Critical signals | [ ] Pass / [ ] Fail | |
| USB programming | [ ] Pass / [ ] Fail | |
| CAN receive | [ ] Pass / [ ] Fail | |
| Listen-only safety | [ ] Pass / [ ] Fail | |
| Isolation sanity | [ ] Pass / [ ] Fail |
Board status: [ ] Ready for bench NMEA 2000 testing / [ ] Requires rework
Prerequisites
1. Visual Inspection
2. Power Rail Verification
3. Critical Signal Verification
4. Connector and Interface Tests
5. Programming and Debug
6. Functional Validation
7. Open Bring-Up Risks
Pass/Fail Summary
