The LINK™ Family Manual
Version 1.6 ©iButtonLink, LLC 2016
Page 14
Arrival/Departure Scanning
Command “ $ ” (dollar sign)
Command Compatible With:
Link | LinkHub-S | LinkHub-E | LinkOEM |
LinkUSB
This command starts the arrival/departure scanning for some LINK
TM
devices. Figure 1 below
shows an arrival on a LinkUSB. Scanning is terminated by a Reset, First, Next, or a number of
other operations.
N
OTE
:
A bus scanning function is included in many LINK products to scan and report the arrival
or departure of a new 1-Wire® device on a 1-Wire® bus. When turned ON using the “ $ ”
command, the scanning system continually performs “First” and “Next” device discovery
operations. It will build a table of device serial numbers, reporting up to eight (for LinkHub-S
and LinkHub-E) or 10 (for Link, LinkOEM, and LinkUSB) devices. The
arrival
will be reported
as a string with an exclamation point (!), a comma (,), and then the arriving device’s serial
number. The
departure
will be reported as a question mark (?), followed by a comma (,), and
then the serial number of the device departed from the bus. This will make sure that the device is
actually gone by doing multiple reads.
On The LinkHub-E and LinkUSB,
the current contents of the table can be reported with a “ * ”
(asterisk) command while scanning is active.
N
OTE
:
The scanning system will not work properly if more than eight (for LinkHub-S and
LinkHub-E) or 10 (for Link, LinkOEM, and LinkUSB) 1-Wire® or iButton® devices are present
on the bus. Exceeding these numbers will exhaust the Link’s memory capacity.
! , 8000000202214928
! , 9A00000208AC5528
? , 8000000202214928
? , 9A00000208AC5528
Figure 1: Command " $ " showing the arrival of a
T-Sense and a T-Probe on a LinkUSB
Figure 2: Command " $ " showing the departure of
a T-Sense and a T-Probe on a LinkUSB