Echelon ISI - Manual (Page 41)

39 ISI Programmer’s Guide
You can eliminate this additional resource usage by deleting and re-creating a
connection instead of extending it.
You can provide feedback to the user when an invitation is accepted, for example
by changing the state of the Connect light from flashing to solid on when the
connection invitation is accepted. This is typically only done with manual
enrollment. The ISI engine informs your application that a connection invitation
has been accepted by calling the IsiUpdateUserInterface() callback function,
assigning the isiApproved or isiApprovedHost state to the respective assembly.
This allows the application to indicate the accepted connection invitation.
E XAMPLE 1
The following manual enrollment example accepts a connection invitation
when the user presses a Connect button. The user can press the Connect
button for a long or short period, causing a destructive or constructive
operation. In the context of accepting a connection invitation, the
constructive operation is to accept. No destructive operation exists at this
stage, but once the connection invitation has been accepted but not
implemented yet, the destructive operation would be to cancel out from the
previous acceptance. Using a second button or some other suitable means,
the Connect button’s meaning also can be altered much in the way a Control
or Alt key on a computer keyboard does. In the context of accepting a
connection invitation, the regular operation could be to create a connection by
replacing any previous connection related with the same assembly, if any.
The alternative behavior could be to always extend the connection, thus
preserving any previous connections, if any.
IsiEvent isiState;
void ProcessIsiButton(unsigned Assembly, boolean Constructive,
boolean Alternative) {
switch(isiState)
{
...
case
isiPending:
if (Constructive) {
if (Alternative) {
IsiExtendEnrollment(Assembly);
}
else {
IsiCreateEnrollment(Assembly);
}
}
break;
... //Processing for other states
} // end of switch(state)
}
// IsiUpdateUserInterface is called with isiApproved as the
// IsiEvent parameter in response to accepting the enrollment
void IsiUpdateUserInterface(IsiEvent Event, unsigned Parameter) {
... //Optional event processing
isiState = (Event == isiPending || Event == isiApproved
|| Event > isiWarm) ? Event : isiNormal;
}
mtimer repeating IsiTimer = 1000ul / ISI_TICKS_PER_SECOND;
when (timer_expires(IsiTimer)) {
unsigned
Assembly;