• 1-Wire
  • Intermediate
  • 5 min
  • Serial CLI

Recipe · Intermediate · 1-Wire

How to sniff 1-Wire bus timing

Use 1-Wire sniff mode to observe reset, presence and bit timing on a Dallas-style single-wire bus.

1-Wire bus with target devices.
A practical ESP32 Bit Pirate recipe based on documented firmware commands.
Step 1

Commands

Run this sequence from the CLI. Adjust pins, addresses or filenames to match your own setup.

Result

What it means

You can see whether the bus is alive before trying read, temp, ibutton or EEPROM operations.

Troubleshooting

  • Re-enter the selected mode setup if pins changed.
  • Confirm the target shares ground with the ESP32 Bit Pirate.
  • Start with short commands before using longer capture or bridge sessions.

Next steps

  • Use scan to enumerate devices after timing looks clean.
  • Use read to inspect ROM and scratchpad data.
  • Move to the EEPROM or iButton shell for device-specific workflows.

1-Wire sniffing FAQ

What does 1-Wire sniff mode detect?

It passively watches the data line and tries to recognize reset pulses, presence responses and bit-slot timing. Use it to confirm bus activity before decoding higher-level meaning.

Can sniff mode replace scan or read?

No. Sniffing observes traffic generated by another master, while scan and read actively talk to devices. Use sniff for timing visibility and active commands for controlled tests.

What timing information does the 1-Wire sniffer preserve?

It preserves the timing relationship between reset, presence and data pulses so you can understand whether a 1-Wire master and target are exchanging recognizable bus activity.

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