OneWire: general ideas


OneWire, or "w1", is a low-speed bus for short distances
More like I2C or SPI than USB
It supports longer distances than I2C, but a much lower data rate

Designed by Dallas Semiconductors (now part of Maxim)
No other vendor, so far (patent-related?)
You can buy thermometers, eeproms, and MAC addresses.

W1 is actually two wires, or three
Ground
The data line
Optionally, a power supply

You usually can drive it from GPIO lines
Some vendors offer a logic cell in the SoC