• 2WIRE
  • Intermediate
  • 5 min
  • Serial CLI

Recipe · Intermediate · 2WIRE

How to probe an SLE4442 smartcard ATR

Open the 2WIRE smartcard shell and probe an SLE4442 card to read its ATR before any memory operation.

SLE4442 smartcard inserted in a reader.
A practical ESP32 Bit Pirate workflow based on the documented firmware commands.

Wiring View

BP CLK2WIRE clock pinIO2WIRE data pinVCC/GNDsmartcard suppl...
Generated from the wiring summary: to BP.
Step 1

Commands

Open the smartcard shell from 2WIRE mode, then choose Probe in the interactive menu.

Result

What it means

The output confirms that the protocol path is working and gives you a baseline for deeper experiments.

Troubleshooting

  • Check physical card orientation and contacts.
  • Re-enter 2WIRE mode if CLK or IO pins changed and follow the setup prompts.
  • Do not try unlock or write steps until Probe is reliable.

Next steps

  • Run the smartcard security check.
  • Dump memory before modifying anything.
  • Keep the ATR in your project notes.

SLE4442 ATR probe FAQ

What does the ATR prove?

The ATR proves that the card responds to reset and that the 2WIRE smartcard shell is communicating well enough for read-only discovery.

Why should Probe come before dump or unlock?

Probe is the lowest-risk confirmation step. It helps identify the card path before memory reads, PSC checks or writes that depend on stable contacts and timing.

What does ATR or probe prove before card operations?

It proves that the card contact path and 2-wire session are good enough to identify the card family. That makes later read, status or lab write steps easier to interpret.

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