1-wire

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(rough draft.)
 
(add references, etc.)
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[[Media: A Guide to the 1WRJ45 Standard.pdf]]
 
[[Media: A Guide to the 1WRJ45 Standard.pdf]]
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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
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may be labeled with the following 2-letter PCB silkscreen abbreviation:
 +
 +
  1 5R (VCC return)
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  2 +5 (VCC power)
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  3 AR (Analog return) (?)
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  4 OW (one-wire I/O)
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  5 OR (one-wire return)
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  6 AS (Analog signal) (?)
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  7 +V (V raw power)
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  8 VR (V raw return)
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== Further reading ==
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[[Wikipedia: 1-Wire]]
 
[[Wikipedia: 1-Wire]]
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to send power and data from the host to the parasitic-power 1-wire device,
 
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.
 
and an optocoupler to send data from the 1-wire device back to the host.
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 +
* [http://owfs.org/index.php?page=hubs 1-Wire File System (OWFS): "1-Wire Hubs"] describes several types of 1-wire hubs.
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* [http://www.simat.org.uk/ "SIMAT Electronic Projects"] has many links to 1-wire hubs, 1-wire weather station, other 1-Wire Projects, etc.
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* The hw-group publishes [http://www.hw-group.com/products/poseidon/pos_interfaces_en.html "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 [http://www.hw-group.com/products/sensors/index_en.html "Sensors, Detectors and accessories"].
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* The [http://www.midondesign.com/Documents/1-Wire%20Application%20GuideOO103.pdf "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.
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* The [http://www.shellypark.co.nz/?q=node/2 "Shelly Park Weather Station"] uses a bunch of 1-wire sensors connected to a 1-wire hub.
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* [http://beehivesleuth.com/onewire/pictures.php BeeHiveSleuth: "My 1-Wire Setup"] has detailed photos of a 1-wire network, including temperature sensors inside a bee hive.
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* [https://sites.google.com/site/raspberry1wire/ "Using the Hobby Boards 6-channel 1-wire master hub with Raspberry Pi"]
  
  

Revision as of 19:36, 2 November 2014

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

Wikipedia: 1-Wire

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.


Is it true that "IEEE 1451.4 uses the Dallas Semiconductor "one-wire" interface" ?

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