SECTION 3 |
22
USING GPIO & DATA WITH ZEPHYR IPORT PLUS
Similarly, the iPort’s decoders use multicast event reports to report to consoles about events that were received
from the codec link.
Both encoders and decoders monitor the GPIO multicast transport channel to receive GPIO state read requests,
and they use multicast messages to report the states requested.
If no Livewire channel number is assigned, the console commands will not be received by the iPort, and notifica-
tions will not be generated, while the LWRP interface operations will not be affected.
Transit Point
The Transit Point mode serves for forwarding GPIO events between a GPIO node connected on the local side of the
Zephyr iPort PLUS, and the codec link. The transit point mode differs from the endpoint mode by the following:
♦
Zephyr iPort PLUS - encoder: On the hardware GPIO node connection it acts as a client, not server.
♦
Zephyr iPort PLUS - decoder: The snake is not terminated in iPort, therefore GPI events received from the
codec link are forwarded to client connections.
♦
It functions as GPI, rather than being translated to GPO.
Snake between GPIO nodes
There is a set of virtual GPI pins associated both with each encoder, and with each decoder. When two iPorts are
connected via a codec link, GPI states in the decoder automatically follow the corresponding GPI states of the
connected encoder.
This mode requires specifying an address of a GPIO event source to be followed - port of a GPIO node connected on
the local side of the encoder.
The address is entered into encoder’s configuration interface in URL format:
<ip address>[:<udp port number>]/<GPI port number>
This configuration determines the association between the source GPIO port number n in the node and the GPIO
port number m in the iPort- encoder. The iPort-encoder (client) would set up a snake connection (“CFG GPO”
command) with the specified GPIO node/port (server) that it has to follow. Further, port numbers found in GPI
events received from the GPIO node will be automatically translated, and events will be accordingly directed to the
linked GPIO ports of the encoder.
LWRP clients can inject GPI events directly into the encoder instance m, bypassing the GPIO port number
translation that is applied to server events. Further these logic states would be memorized and forwarded over the
codec link identically with those received from a node.
Similarly, LWRP clients can inject GPI events directly into the decoder, overriding the states received via the codec
link from the connected encoder. These GPI events would be memorized in the decoder and indicated to other
LWRP clients identically with those received from the codec link.
LWRP clients can read the logic states from encoders or decoders using the GPI command, or they can subscribe
(ADD GPI) to receive automatic GPI change notifications in the standard way. The following exceptions apply:
GPI state changes in the encoder, initiated by the locally connected GPIO node that is acting as a server (snake
origin), do not trigger event reports back to the server.
GPI state changes in the decoder, initiated by the codec link, do not trigger event reports back to the codec link.
