SECTION 3 |
21
USING GPIO & DATA WITH ZEPHYR IPORT PLUS
The four operation modes are:
♦
Virtual Endpoint
♦
Transit Point
♦
I/O Emulation
♦
Controller Emulation
First, a Few Definitions
As with most IT technologies, Livewire uses acronyms. You don’t need to know these in order to set up the GPIO
functions, but there are a few terms that will be used frequently in the following explanations:
LWRP
– LiveWire Routing Protocol
GPIO
- General Purpose Input-Output
GPI
– General Purpose Input
GPO
– General Purpose Output
LWCH
– LiveWire CHannel number
Virtual Endpoint
The virtual endpoint mode serves for forwarding the GPIO events between clients (PC applications, Axia con-
soles) connected on the local side of the Zephyr iPort PLUS, and the codec link. In the endpoint mode, the decoder
terminates the snake, therefore in the decoder the GPI events received from the codec link are translated to virtual
GPO states. This is functionally equivalent to the snake mode of the Axia IP driver.
Snake between virtual endpoints in Zephyr iPort PLUS
There is a set of virtual GPI pins associated with each encoder and a set of virtual GPO pins associated with each
decoder. When two iPorts are connected via a codec link, GPO states in the decoder automatically follow the
corresponding GPI states of the connected encoder.
LWRP (LiveWire Routing Protocol) clients can set and read the states of both GPI pins in the encoder and GPO
pins in the decoder, as well as receive change notifications in the standard way. Axia consoles can set the states of
GPI pins in the encoder and receive state change notifications about GPO pins in the decoder. GPI states set in the
encoder using any of the two methods above would be forwarded over the codec link to the decoder. GPO states set
directly in the decoder and states received over the codec link would override each other on the last-arrived basis.
To enable interfacing with an Axia console, a Livewire channel number must be assigned to the corresponding
GPIO port of an encoder or decoder, by means of the configuration UI. The iPort’s encoders monitor the common
GPIO multicast transport channel, to receive events from consoles. The events are reported using multicast
command messages and addressed to a specific Livewire channel.
