Card-Crack: Cardputer ESP32-S3 home-lab recon toolkit

Manual-trigger firmware toolkit for pentesting owned devices:
- Pin Scan: UART/JTAG/SWD detection (baud est + IDCODE reads)
- V-Sense: target voltage probe w/ logic-family guess
- UART Sniff: passive capture + manual-only frame replay
- USB Enum: ESP32-S3 host, read-only descriptor fingerprinting
- DefCred: single-host factory-default login check, rate-limited

Modular shell (core/ + modules/), PlatformIO build, hardware/safety docs.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AAhMHMRAQLQ9hSbBECKNfn

docs/HARDWARE.md

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+# Hardware & wiring — read before probing
+
+The Cardputer's ESP32-S3 is a **3.3 V** part. Several targets you'll poke are
+not:
+
+- Car OBD/USB, PC USB: **5 V** VBUS.
+- Some debug headers idle at 1.8 V.
+
+**Always** go through protection. Never land a probe on a live target until
+V-Sense has told you the voltage.
+
+## Probe header
+
+`src/core/pins.h` defines `pins::PROBE[]`. By default:
+
+- `G1`, `G2` — the side Grove connector (safe, use these first).
+- `G8..G13` — StampS3 pads via a breakout ribbon (optional).
+
+## Minimum protection rig
+
+| Signal        | Between probe and target                              |
+|---------------|-------------------------------------------------------|
+| Any GPIO in   | 1 kΩ series + 3.3 V clamp (BAT54S to 3V3/GND)         |
+| V-Sense (G10) | resistor divider R1:R2 = 2:1 → 0–9.9 V range (ratio 3)|
+| Level shift   | bidirectional shifter (e.g. TXS0108) for 5 V buses    |
+
+Adjust `pins::VSENSE_RATIO` if you change the divider.
+
+## USB host
+
+To use **USB Enum** the S3 must supply VBUS to the target as a host. Use an
+OTG adapter on the S3 USB port, keep the CDC console on the built-in USB, and
+never hot-plug a 5 V target onto a GPIO — it goes on the USB D+/D-/VBUS lines
+only.
+
+## Safety checklist
+
+1. Target powered from its **own** supply, common ground with the Cardputer.
+2. V-Sense the line first. If it reads ≥ 5 V, shift or stop.
+3. Start passive (Pin Scan / UART Sniff). Only replay/TX when you mean to.
+4. It's your device. Keep it that way.