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Phase 2 — Power the TFT

Three wires to the display only. Backlight is the quick check. Leave the GNSS alone.

Firmware

Unchanged — firmware/01-hello/.

Preconditions

Checkpoint 1 done. TFT 8-pin header on. Unplug USB while seating jumpers.

Warning

Power the TFT from 3V3 only — 5V on the logic can kill the module. After wiring, check for heat and ~3.3 V on VCC before trusting it.

Wires

Phase 2 — TFT power

From ESP32 To
3V3 TFT VCC, TFT BL
GND TFT GND

Match 3V3 / GND by silk. Star on the breadboard rails (how the board is tied). TFT SPI pins stay open.

Check

Plug USB. Module cool. Meter ≈ 3.3 V on TFT VCC. Backlight on. After unplug/replug the port may move (ttyUSB0 → ttyUSB1) — check with ls /dev/ttyUSB* first.

pio device monitor -b 115200 --port /dev/ttyUSB0

gnss-field hello MAC=8C:94:DF:6D:C9:5C uptime_ms=5080613

Checkpoint 2

  • [x] Those three TFT wires only
  • [x] ~3.3 V, backlight on, no heat
  • [x] Hello still prints
  • [x] Lab log

Next: Phase 3 — GNSS power