uart-console

Use when physical access is available, and you need an interactive root shell without desoldering chips or risking firmware corruption.

1. Pin identification

• Visual: Look for 3-4 unpopulated through-holes or test pads near the SoC.
• Multimeter:
  1. GND: 0 V (continuity with shielding).
  2. VCC: 3.3 V or 5 V (constant).
  3. TX: Idle HIGH (3.3 V), fluctuates during boot.
  4. RX: High-impedance (floats to ~0 V or pull-up).
• JTAGulator: Use UART scan capability if pads are unlabeled/dense.

2. Connection

Rule: Do NOT connect VCC if the device is self-powered. This causes voltage collision.

• Connect: GND → GND, RX → TX_pad, TX → RX_pad.