Industrial MESBox Controller Design
Configure 100Ω Ethernet rules, route the Ethernet pairs first, then run full DRC.
Thought for 11 sec
I’ll configure the Ethernet nets for 100 Ω differential routing, route the Ethernet pairs first, then run a full DRC and report the remaining board issues.
Thought for 15 sec
I’m blocked because the account has no available ACUs, so I can’t configure routing rules, route traces, or run DRC right now.
Accomplished before this request:
- Ethernet schematic support was completed: RJ45 center taps, LEDs, ESD arrays, KSZ9477 straps/clock/reset/MDIO, and CM4 uplink.
- Ethernet block placement was completed: RJ45s on the board edge, ESD arrays behind them, KSZ9477 behind the protection row, and crystal/load caps near U61.
- Ethernet layout constraints were documented in the project file.
Remaining work when ACUs are available:
- Configure 100 Ω differential-pair rules for all Ethernet pairs.
- Route Ethernet pairs first from RJ45 → ESD → KSZ9477.
- Route remaining power/control nets.
- Run full DRC and fix/report remaining layout violations.
Review constraints
List Ethernet pairs
Manual routing checklist
Estimate pair geometry
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Board Bring-Up Plan — Industrial MESBox Controller
Prerequisites
- Current-limited 24 V bench supply, multimeter, oscilloscope, STM32 SWD debugger, Ethernet tester, and Linux SOM serial console.
- Start with outputs unloaded and field I/O disconnected.
1. Visual Inspection
- Verify orientation of SOM connector/module, STM32, regulators, TVS diode, ideal-diode controller, STISO isolators, SPI flash, and polarized capacitors.
- Inspect RJ45 shield tabs and chassis bonding network.
2. Power Rail Verification
Table
| Rail | Source | Expected | Initial Current Limit | Pass Criteria |
|---|---|---|---|---|
| 24V_IN_RAW | Input connector | 24 V DC | 200 mA first power | No reverse-protection heating |
| 24V_PROTECTED | LTC4359 + filter | ~24 V minus MOSFET drop | 200 mA | Correct polarity, no oscillation |
| 5V_LOGIC | D24V50F5 buck | 5.0 V | 500 mA | 4.85–5.15 V |
| 3V3_LOGIC | LMR33630 | 3.3 V | 500 mA | 3.20–3.40 V |
| 24V_OUT_FIELD | protected field domain | 24 V | load-dependent | Separated from logic rail |
3. Critical Signals
Table
| Signal | Expected |
|---|---|
| NRST | High after 3.3 V is valid |
| WDI | STM32 toggles periodically after firmware starts |
| BOOT0 | Low for normal STM32 boot |
| SWDIO/SWCLK | Programmer can read STM32 device ID |
| CNT1/CNT2 | Count 10 kHz square wave without missed pulses |
4. Functional Tests
- Bring up logic rails without SOM installed if possible.
- Program STM32 via SWD and verify watchdog heartbeat.
- Install SOM and verify boot console.
- Test six buttons and display UI path.
- Apply 24 V to each isolated input and verify STM32 state changes.
- Apply 10 kHz test pulses to counter inputs and compare counts over 60 s.
- Test each transistor output with resistive load first, then representative inductive load with clamp temperature monitoring.
- Validate all three Ethernet ports with link, DHCP/static IP, and sustained traffic.
Open Bring-Up Items
- Add explicit test points in schematic/layout for all rails, SWD, reset, watchdog, field common, and each output.
- Finalize output driver MPN before production validation.
- Finalize Ethernet switch/expansion architecture for three physical RJ45 ports.
Prerequisites
1. Visual Inspection
2. Power Rail Verification
3. Critical Signals
4. Functional Tests
Open Bring-Up Items
