Introduction:
The LinkHub-E™ is an advanced, intelligent, multiport network interface for use with
Dallas Semiconductor 1-Wire™ and iButton™ components. It uses superior digital and
analog methods to accomplish reliable operation on a wide variety of network topologies.
It also offers many functions that simplify network communications and some diagnostic
tools as well.
There are five (5) 1-Wire busses (1 internal and 4 external) which are logically or-ed into
a single composite 1-Wire bus. Software written for the Dallas Semiconductor DS2480B
interface will work even though the 1-Wire devices are physically on separate busses.
Each external bus can be up to 1000 feet long. This yields a logical 1-Wire network of
4000 feet with 4 times the network weight of a standard 1-Wire bus.
The LinkHub-E pr12V and +5V power on the 1-Wire bus cables.
The LinkHub-E is designed to operate reliably on long and short 1-Wire busses. This is
accomplished by a special analog interface design that uses matched impedances and
slew rate controls, as well as smart cable pre-charge. The firmware (programming) is
adaptive and automatically adjusts many 1-Wire network parameters.
The LinkHub-E is based on the Link, designed in cooperation with Dallas Semiconductor
Corp., Dallas, Texas, the originator of 1-Wire and iButton devices and various
accessories. Some terms used in this document may be trademarks of Dallas
Semiconductor Corporation, and are used with their permission.
DS2480B Emulation:
The LinkHub-E is programmed to closely emulate a Dallas DS2480B serial port to
1-Wire line driver so that existing software can use it without modification. This allows
The LinkHub-E to be used in place of the Dallas DS2480B in most cases where increased
performance or reliability is required. Some DS2480B functions are not emulated by the
LinkHub-E, as described below. DS2480B Emulation will be removed in a future
LinkHub-E firmware release.
Calibration:
Unlike the DS2480B, the LinkHub-E does not require calibration from the serial port
because it has a crystal-controlled time base. This means that drift in the interface data
rate and waveform timing is not an issue. The LinkHub-E expects a calibration byte for
DS2480B software compatibility but it is ignored.
Copyright © 2008 by iButtonLink LLC
iButton and 1-Wire are trademarks of Dallas Semiconductor Corp, Dallas, Texas, USA.
2 of 17
