User manual

WiFly GSX/EZX
www.rovingnetworks.com WiFly-RN-UM 11/9/2011
809 University Avenue • Los Gatos, CA 95032 • Tel [phone] • [e-mail]
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11.2. UDP Auto Pairing
UDP auto pairing feature temporarily stores the Host IP address of the first remote device that send a UDP
packet into the module. This host IP address is stored in the RAM which will not survive a sleep or power
cycle.
This feature allows the WiFly module to echo back to any client that sends a UDP packet. To use this
feature, the host IP addresses and set the ip flags.
set ip host 0.0.0.0
set ip flags 0x40
11.3. UDP Retry
This feature adds a level of reliability to the UDP protocol without adding the complete overhead of TCP
protocol. When enabled, the module waits for a response on every UDP packet sent, (any UDP packet
coming back in). If the response packet is not received by approximately 250 ms, the same UDP packet is
sent out.
This continues until either
• A UDP response is seen, or
• A new UDP packet is sent from the module and is acknowledged
To enable this feature, use set ip flags <value>
11.4. Using the UDP Broadcast function
The WiFly module can be setup to automatically generate UDP broadcast packets. This is useful for a
number of reasons:
- Some Access Points will disconnect devices that sit idle and don’t send any packets after a time.
Using the UDP broadcast informs the AP that WiFly is alive and wants to stay associated.
- This feature can be used by application programs to auto-discover and auto configure the WiFly
module. If an application is listening for the UDP broadcast, a number of useful parameters are
present in the package that can be used for auto-discovery. For example, the IP address and port
number of the WiFly are both part of the packet, and thus the WiFly can be connected to and
configured remotely with this information.
- The MAC address of the associated AP, channel, and RSSI value are available in this packet, thus
enabling a simple location and tracking based function.
By default the WiFly module now sends out a UDP broadcast to 255.255.255.255 on port 55555 at a
programmable interval. The broadcast address, port and interval are set using the “set broadcast”
commands.