Telegesis (UK) Limited
TG-ETRXn-UG-01-103
28
User Guide
1.04
ETRX1 and ETRX2
©2008 Telegesis (UK) Ltd
ETRXn User Guide (Rev 1.04)
The solution is to specify a common key value in S03; it is not necessary to alter the contents of
S06 that relate to secured joining.
10 Application Examples
In this section there is a list of suggested applications using the ETRXn module. This list will never
be exhaustive, but should give you an idea about the great flexibility and versatility of the Telegesis
ETRXn Wireless Meshing Module.
10.1 Simple Temperature Sensor
Let us assume we have a simple temperature sensor on a remote node and a data-gatherer node
which sinks the data transmitted by the sensor, possibly talking to one another via several relaying
FFDs.
The temperature sensor could be attached to A/D1, and A/D2 can be used to monitor the battery of
the sensing device.
The simplest approach would be to poll the sensor every now and then from the data-
gatherer using the “ATSREM12:<EUI64>?” command. The sensing node could be a
sleepy or mobile sleepy end device as well as a router. The advantage of the later would
be that every sensing node is an FFD and can therefore relay messages forming a reliant
and failsafe meshed network. A host controller would have to initiate the polling operation
on the data sink.
An alternative is to use one of the ET
RXn‟s built-in timers and select a suitable function
from the list of built in functionality which is further explained in section 11, such as 0101 or
0111 (send I/O and ADC readings to sink). This will make the sensor send its temperature
information to the sink periodically. As in the previous option the sensor could be an end
device in power mode 2, thus being battery operated.
10.2 Switch Application
For a classical switch application like a light switch, it is quite obvious that polling is not the right
way forward as this would lead to a massive increase of network traffic.
For this scenario the following methods can be considered:
By setting register S16 to 0100 and enabling the appropriate interrupt in S2E every falling
edge on I/O1 will cause the switch unit to transmit the status of its I/O and both A/D
readings to the sink, which can control the light.
Alternatively, the falling edge on I/O1 can wake up the switch module from power mode 3.
Being a sleepy end device this could lead to many years of battery operated lifetime
depending on how often the switch has been triggered and also the shelf life of the battery.
Starting with firmware version R211, built-in function 0019 allows a device to send the state
of its logic inputs to another node whenever an input changes. The receiving node will set
its outputs to match the incoming pattern, so that switch inputs on one node can be
mirrored to load outputs on another node.
Starting with firmware version R211, built-in function 001B allows a device to read the
inputs of another device and set its outputs to correspond with them. However, this is not
as good as function 0019 as the local node must continually send radio messages to
interrogate the remote node, and if a fast response is needed there will be a lot of radio
traffic that could degrade the network. However, the corresponding one-shot function 001A
