1 Wire Bus

1 Wire Bus Electronic Design & Firmware
by Embedded Design Engineer John Heritage


Dallas Semiconductor’s 1-Wire bus is an asynchronous, master/slave bus with no protocol for multi-master. Like the I2C bus, 1-Wire is half-duplex, using an open-drain topology on a single wire for bidirectional data transfer. However, the 1-Wire bus also allows the data wire to transfer power to the slave devices, although this is somewhat limited. Though limited to a maximum speed of 16Kbps, bus length can be upwards of 1,000 feet, given the proper pull-up resistor.