ClearOne Writing StreamNet User Manual

Page 48

Writing StreamNet Device Drivers

C-2

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The example also uses two timer driven functions, pollResponse and queryStatus. The
first function, pollResponse, reads data from the serial port every second looking for
messages from the device. Depending on what the response is, the driver may turn the
indicatorState variable on or off (1 or 0 respectively). The second function queryStatus
will send a query to the device every 10 seconds to ensure that the driver stays in sync
with the device. These functions are created by calling the createTimer function.
--

-- The service itself is set up with a subNode for

each of the switchable

-- power supplies (switchable outlets and high power

outlets) and a subNode

-- for all power. Each zone responds to a #BUTTON

PRESS by sending out

-- the requested command and then issuing an

?OUTLETSTAT to find out which

-- outlets are on.

-- To allow the GUI to display an appropriate label

on the button, each

-- subNode also reports status in the common form:

-- text>" indicatorState="<0/1>" />

-- We have to create our functions first then we can

use them below

-- function createButton( Name, Label, xmitString )

-- create a button node

function

createButton( Name, Label, xmitString )

-- create a subNode for each button

local

node = createSubNode(Name)

-- the serial to xmit string that dealer setup writes

for us

has escape sequences so that special characters

like newlines

and nulls can be embedded in the string to

send. Each escape