Users Manual Part 1

FOX3-2G/3G/4G HARDWARE MANUAL VERSION 2.2.5
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7.2.2. 1-Wire interface description
A 1-Wire bus uses only one wire for signaling and power. One or several 1-Wire devices can be connected to the bus
at the same time. Only one master should be connected to the bus.
Driver identification, temperature and humidity sensors are quite often used on vehicle applications. Thanks to the
integration of 1-wire interface into the FOX3-2G/3G/4G devices, the system integrators for telematics, fleet
management and intelligent transportation system can be cost-benefit and time efficiently for their work due to the
use of extra external devices which are not integrated in the in-vehicle computers. Using of the 1-Wire interface, you
are able to know which drivers are in which vehicles and at the same time monitor the temperature and humidity of
their refrigerated trucks. In this way, shippers can record by their server the transportation and the delivery state of
their temperature-sensitive loads.
How does it work?
A 1-Wire network consists of a master controller which is connected to one or many slave devices. The 1-Wire
interface on FOX3-2G/3G/4G is a master controller. All of the actual monitoring devices (lightning detector,
moisture meter, motion detector, barometer, etc.) are slave devices. FOX3-2G/3G/4G communicate with
temperature and iButton devices via 1-Wire protocol developed by Dallas Semiconductor, sending and receiving
signals over a single data line plus ground reference. The 1-Wire protocol synchronizes the monitoring devices to
the FOX3-2G/3G/4G. FOX3-2G/3G/4G initiate and requests all activities on the 1-Wire network. One key feature of
the Dallas system is that every 1-Wire slave device has a guaranteed unique address saved on-chip ROM (Read Only
Memory). This enables the master to recognize individually each of your slave devices, and means you can have
multiple devices of the same type on the same network without conflict.
Figure 13: Typical application connection
Setting up a 1-Wire network with the FOX3-2G/3G/4G devices is quite easy. 1-Wire is a simple system of devices
such as temperature, iButton devices etc. that are connected through the 1-Wire data line plus ground reference
to the FOX3-2G/3G/4G devices. Remember that you can use and connect to the FOX3-2G/3G/4G 1-Wire line only
sensors that require power supply anywhere between 2.9V and 5.0V. FOX3-2G/3G/4G devices receive on demand
the unique address of the temperature and iButton IDs and other information they deliver. This information can
then be sent via alarms to the remote TCP server.
Figure 13.1: Typical application using 1-Wire single line.
More details about the 1-Wire interface, refer to the application note "AppNote_1-Wire_Guide.pdf".