Frozen Placement DRC Routing
Thought for 2 mins 2 sec
I’ll continue from the current partially routed board with the new permission: small local moves are allowed in the USB/display/power areas, then I’ll route and verify DRC.
Worked for 7 mins 46 sec
The local placement pass unexpectedly nudged U3 despite the instruction not to move it, so I’m restoring that mechanical constraint first and then cleaning up the stale trace issues before routing.
Thought for 29 sec
I read the attached routing instructions, inspected the current board state, and confirmed the board still had 48 airwire DRC errors before making changes. I then ran a small-local-placement pass intended to open routing channels, but it unexpectedly nudged U3 despite the “do not move U3” constraint and introduced overlapping copper from stale routing.
Open items:
- Restore/verify U3’s intended placement and antenna keepout.
- Clean up the newly introduced overlapping copper/stale traces.
- Continue routing remaining airwires.
- Add/verify GND pours and run final DRC.
I’m blocked from continuing because the account currently has no available ACUs, so AI execution tools are unavailable right now.
Restore U3 cleanup
Prioritize DRC errors
Remove stale traces
Verify U3 placement
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Board Bring-Up Plan — Mini Retro TV
Prerequisites
- Multimeter, current-limited USB supply or bench supply, oscilloscope if available, USB-C cable, protected 1-cell LiPo, and test firmware from the Firmware Starter file.
- Start with the slide switch OFF when checking charging.
- Use a protected LiPo cell; the board does not include a dedicated battery protection IC.
1. Visual Inspection
- Check USB-C, MCP73831, XC6220, ESP32-C3 module, MOSFETs, LEDs, JST polarity, and Hall sensor orientation.
- Confirm no solder bridges on USB-C, ESP32-C3 castellations, and ST7789 display header.
- Verify charge LEDs are oriented correctly.
2. Power Rail Verification
Table
| Rail | Source | Expected Voltage | Measure At | Initial Current Limit | Pass Criteria |
|---|---|---|---|---|---|
| VBUS_RAW | USB-C | 5.0 V | J1/F1 input | 100 mA | 4.75–5.25 V |
| VBUS | F1 output | 5.0 V minus fuse drop | U1 VDD / C1 | 100 mA | Present when USB connected |
| BAT+ | LiPo / MCP73831 | 3.0–4.2 V | J2 pin 1 / C2 | 100–300 mA | No reverse polarity; charges toward 4.2 V |
| VSYS | Slide switch | BAT+ when ON | TP3 / U2 VIN | 100 mA first power | Switch fully disconnects system when OFF |
| 3V3 | XC6220B331MR | 3.3 V | TP1 / U3 3V3 | 100 mA first power | 3.20–3.40 V no-load/light-load |
3. Critical Signal Verification
Table
| Signal | Expected State | Measure At | Notes |
|---|---|---|---|
| EN | High after RC delay | TP4 | Low disables ESP32-C3 |
| GPIO2_STRAP | High | TP6 | Must not be forced low at reset |
| BOOT_GPIO9 | High idle, low when eject pressed | TP5 / SW2 | Doubles as eject and BOOT |
| USB_DP_MCU / USB_DN_MCU | USB full-speed activity | TP7 / TP8 | Check only after firmware/USB enumerates |
| HALL0/1/2 | Pull-up high, low when active | U4-U6 OUT | Depends on magnet polarity and latch state |
| BAT_ADC | About VBAT x 150k/(470k+150k) | U3 IO1 / C7 | 4.2 V battery gives about 1.02 V |
4. Connector and Interface Tests
Table
| Connector | Test |
|---|---|
| J1 USB-C | Verify VBUS, GND, CC pull-downs, and USB enumeration |
| J2 JST-PH | Verify polarity before plugging battery |
| J3 Display | Verify pinout: VCC, GND, SCK, MOSI, CS, DC, RST, BLK |
| TP1-TP8 | Verify labels against 3V3, GND, VSYS, EN, BOOT, GPIO2, USB D+, USB D- |
5. Programming and Debug
- Connect USB-C.
- Confirm the ESP32-C3 enumerates as USB Serial/JTAG.
- If upload fails, hold Eject/BOOT low while resetting/powering.
- Flash the starter firmware with PlatformIO.
- Confirm serial monitor prints cassette ID and battery voltage.
6. Functional Validation
Table
| Test | Expected Result |
|---|---|
| Red charge LED | On while MCP73831 is charging |
| Green charge LED | On at charge-complete state for MCP73831-2 STAT behavior |
| Slide switch | OFF disconnects VSYS/3V3 system power; charger still charges battery from USB |
| Display | ST7789 initializes and prints status text |
| Backlight | Firmware PWM controls brightness via Q1 |
| Hall sensors | 3-bit cassette ID changes with magnet positions |
| Eject/BOOT | Button reads low in firmware; also can force BOOT mode during reset |
| Piezo | Firmware tone produces beep through Q2/BZ1 |
| Battery ADC | Reported VBAT matches multimeter within calibration tolerance |
Open Bring-Up Risks
- US1881 sensors are not guaranteed below 3.5 V supply.
- Charging while the system is ON may disturb charge termination because MCP73831 is not a power-path charger.
- Display backlight behavior depends on the exact ST7789 module BLK implementation.
Prerequisites
1. Visual Inspection
2. Power Rail Verification
3. Critical Signal Verification
4. Connector and Interface Tests
5. Programming and Debug
6. Functional Validation
Open Bring-Up Risks
