Telegesis (UK) Limited
TG-ETRXn-UG-01-103
13
User Guide
1.04
ETRX1 and ETRX2
©2008 Telegesis (UK) Ltd
ETRXn User Guide (Rev 1.04)
3.3.10 AT+REMSN
– Scan for remote device’s direct neighbours
This returns the direct neighbours of a remote device. Optionally the RSSI and LQI readings
between the remote device and the reporting device can be displayed if bit 6 of register S06 is set
as described in section 5.
3.3.11 AT+LINKCHECK - Check link parameters with a neighbour
This gives you the opportunity to check the RSSI and LQI between the local node and a direct
neighbour without the delays inflicted by AT+SN.
3.3.12 AT+PING - Indicate presence in the network
A remote device can indicate its presence in the network by pinging out its ID when instructed by
the “AT+PING” command. All devices receiving the ping that have bit 6 of register S06 set will
display the RSSI and LQI.
3.3.13 ATS & ATSREM
– Read and write S-registers
“ATSxx?” returns the contents of local register xx, while “ATSxx=XXXX” sets it to XXXX. The
corresponding syntax for register xx of remote node <EUI64> is “ATSREMxx:<EUI64>?” and
“ATSREMxx:<EUI64>=XXXX”. The S-registers control the module‟s functions and I/O; for
example “ATS0F=0000” clears all the bits of the output register 0F, and for a module on a Devkit
board lights up all the LEDs. “ATSxxy” or “ATSREMxxy” accesses bit y alone of register xx.
3.4 Managing a Network
Previously we used the AT+SN command to scan the network for other nodes. Having found
them, we were able to interact with those nodes by referencing them using their unique serial
number.
Nodes can also be asked to disassociate from the coordinator both locally as well as remotely by
the coordinator itself,
using the “AT+DASSL” and “AT+DASSR” commands respectively.
By default, remote nodes are automatically permitted to join a PAN, but various bits in register S06
can set a secure restricted joining mode or can close a PAN to all new members.
All these commands may seem a lot to memorise at this point, but their use will become more
obvious once you have looked at the examples in Section 10.
3.5 Maintaining a Network
A network is self-healing, which means that if a certain path between two nodes breaks, the mesh
will find a new path to make communication possible, unless one of the nodes has simply gone out
of range of the entire network.
Each node periodically checks it has not lost its neighbouring devices; if it has lost connectivity to
its PAN, it leaves the network (default function of Timer 4). A module that is not part of a network
periodically searches for one that it can join (default function of Timer 3); hence a node may
temporarily drop out of the net and come back in again, possibly via a different parent node if it has
moved. If there is a risk that a node may drop out and be re-captured by a different PAN, security
modes should be invoked (see section 8).
