Echelon ISI - Manual (Page 55)

53 ISI Programmer’s Guide
void IsiUpdateUserInterface(IsiEvent event,
unsigned parameter) {
if (event == isiPending || event == isiPendingHost) {
SetConnectLed(LED_BLINKING);
} else if (event == isiApproved ||
event == isiApprovedHost) {
SetConnectLed(LED_ON);
} else {
SetConnectLed(LED_OFF);
}
deviceState = event;
}
SetConnectLed() is a device-specific function that is defined elsewhere. The
function sets the device’s LED into the three states mentioned above. While the
default implementation of the IsiUpdateUserInterface() function contained in the
ISI implementation library does nothing, the overridden implementation above
connects the ISI engine with the user interface—a single LED in this case.
The second parameter of IsiUpdateUserInterface() generally indicates the
assembly number to which the event applies. Since the sample device only has
one assembly, the parameter is disregarded here.
ISI requires no specific user-interface, but a simple user interface is typically
required for devices that implement manual connections. A minimal user
interface can be implemented by monitoring state changes to isiPendingHost,
isiPending, isiApprovedHost, isiApproved, and isiNormal for each assembly. To
relay a user command to the ISI engine, you can detect the related user interface
operation and call the related ISI command function. For a small device this user
input device can be as simple as a single Connect button, which may be in one of
three states: 1) not pressed, 2) pressed for a short while, or 3) pressed for a
prolonged period of time. This single-button input is often combined with the
current state of the related assembly, as indicated with the DeviceState tracking
variable introduced above.
The following table summarizes the response to a button press, based on the
DeviceState value.
DeviceState Connection Host Response to Connect Button
isiPendingHost Yes A pending connection host is one
that has issued a connection
invitation (CSMO message) but
has not yet received a single
CSME. In this state, only
cancellation is a valid operation.
Call IsiCancelEnrollment() to
cancel the open enrollment.
isiPending No A pending connection member is
one that has received and
provisionally approved a
connection invitation. Call
IsiCreateEnrollment() or
IsiExtendEnrollment() to accept
the connection.