The LINK™ Family Manual
Version 1.6 ©iButtonLink, LLC 2016
Page 18
Auxiliary Output Isolation Mode
Command “ “ ” (quotation)
Command Compatible With:
Link | LinkOEM | LinkUSB
On LINK
TM
devices, this command will cause the auxiliary output to enter isolation mode and
become an image of the 1-Wire® bus transmitter drive waveform. This signal can be useful
when trying to accomplish an isolated 1-Wire® connection or whenever a 2-Wire connection is
preferred. The original 1-Wire® bus remains unaffected. Figure 4 shows how isolation mode
runs on a 1-Wire® device.
Setting the auxiliary output level using the “ z ” or “ d ” commands will turn this feature off, as
will any reset of the device.
When in the isolation mode, the LINK
TM
devices output the 1-Wire® driving waveform on the
aux pin. This can be used to extend the 1-Wire® bus using other signaling protocols. It can also
be used to isolate the bus using optical or galvanic isolation devices. The following diagram
shows how isolation mode could be used to extend the 1-Wire® port on the LINK
TM
devices.
The LINK
TM
devices also have a mode where the timing of the 1-Wire® waveforms is slowed to
accommodate the longer turn-around times of extended host connections like that shown above.
In normal mode, network lengths of up to 3,000 feet can be used (depending on the medium). In
extended mode, network lengths of between 2,000 and 6,000 feet can be achieved.
S
IMILAR
C
OMMANDS
:
•
“ & ” - Auxiliary Line High Impedance
•
“ d ” – Auxiliary Line High Power and Low Impedance
•
“ z ” – Auxiliary Line Low Power and Impedance
The LINK
Open Drain
Open Drain
1-Wire Devices
Aux
O/W
Figure 4: Isolation Mode Extending 1-Wire® Port on LINK Device