1-wire
rough draft
The 1-wire network is a communications bus system designed by someone(?) at Dallas Semiconductor (now part of Maxim Integrated) that provides low-speed data, signaling, and power, using up a total of one pin on the CPU no matter how many peripheral chips are on that bus. (Other ways of connecting a peripheral to the CPU either require another pin for each peripheral, or require more pins for the first peripheral, or both).
The 1-wire network is perhaps the most popular way to measure temperatures at many different locations and send that data back to one central processor.
Media: A Guide to the 1WRJ45 Standard.pdf
It makes it easier to troubleshoot if each PCB has 2 RJ45 connectors (or a dual RJ45 connector), with 1 LED indicating power and 1 LED indicating 1-wire signals.
For clarity each of the 8 wires from the standard 1WRJ45 connector may be labeled with the following 2-letter PCB silkscreen abbreviation:
1 5R (VCC return) 2 +5 (VCC power) 3 AR (Analog return) (?) 4 OW (one-wire I/O) 5 OR (one-wire return) 6 AS (Analog signal) (?) 7 +V (V raw power) 8 VR (V raw return)
Further reading[edit]
Bich Pham. "One-Wire Serial Bus Carries Isolated Power And Data". http://electronicdesign.com/power/one-wire-serial-bus-carries-isolated-power-and-data The same circuit is also shown in "APPLICATION NOTE 3754: Single-Wire Serial Bus Carries Isolated Power and Data" http://www.maximintegrated.com/app-notes/index.mvp/id/3754 uses a MAX845 transformer driver and a transformer to send power and data from the host to the parasitic-power 1-wire device, and an optocoupler to send data from the 1-wire device back to the host.
- 1-Wire File System (OWFS): "1-Wire Hubs" describes several types of 1-wire hubs.
- "SIMAT Electronic Projects" has many links to 1-wire hubs, 1-wire weather station, other 1-Wire Projects, etc.
- The hw-group publishes "Poseidon HW interfaces for sensor connecting" which has a good description of 1-wire bus on RJ11 connectors and RS-485 bus on RJ45 connectors, as used on their "Sensors, Detectors and accessories".
- The "midon design: 1-Wire Application Guide" lists many tips for wiring up a 1-wire bus, including "some popular connector schemes" on 4-wire, 6-wire, and 8-wire connectors.
- The "Shelly Park Weather Station" uses a bunch of 1-wire sensors connected to a 1-wire hub.
- BeeHiveSleuth: "My 1-Wire Setup" has detailed photos of a 1-wire network, including temperature sensors inside a bee hive.
- Bernhard Linke. Maxim "Application note 5134: Implementing an Isolated 1-Wire Bus".
- 1-Wire File System (OWFS): http://owfs.org/
- has more information on 1-wire bus wiring standards using RJ-11 or RJ45 connectors.[1]
- The main page for using Arduino with 1-wire devices: http://playground.arduino.cc/Learning/OneWire
- read and write 1-wire devices with an 8-bit AVR microcontroller.
- Protocol Tool supports many protocols, including 1-wire.
Is it true that "IEEE 1451.4 uses the Dallas Semiconductor "one-wire" interface" ?
