Installs an interrupt.
[ lStatus = ] EnableInterrupt ( enInterrupt, lParameter, proc )
The EnableInterrupt procedure syntax has the following parts:
|
Name |
Type |
Description |
|
lStatus |
Long |
Return status |
|
enInterrupt |
Val enumAInterrupts |
An integer specifying the INT_xxx interrupt constant. |
|
lParameter |
Val Long |
Parameter for interrupt type |
|
proc |
Val Procedure |
Name of interrupt subroutine, not a string |
enumAInterrupts can be one of the following values:
|
Name |
Value |
Description |
|
INT_TIMER1 |
10 |
TIMER1 Interrupt. The interval expired. |
|
INT_TIMER2 |
11 |
TIMER2 Interrupt. The interval expired. |
|
INT_COM1 |
12 |
COM1 Interrupt. Bytes were received. |
|
INT_COM2 |
13 |
COM2 Interrupt. Bytes were received. |
|
INT_COM3 |
14 |
COM3 Interrupt. Bytes were received. |
|
INT_COM4 |
15 |
COM4 Interrupt. Bytes were received. |
|
INT_COM5 |
16 |
COM5 Interrupt. Bytes were received. |
|
INT_COM6 |
17 |
COM6 Interrupt. Bytes were received. |
|
INT_COM7 |
18 |
COM7 Interrupt. Bytes were received. |
|
INT_COM8 |
19 |
COM8 Interrupt. Bytes were received. |
|
INT_COM9 |
20 |
COM9 Interrupt. Bytes were received. |
|
INT_GPIB1 |
22 |
GPIB1 Interrupt. An SRQ signal was received. |
|
INT_GPIB2 |
23 |
GPIB2 Interrupt. An SRQ signal was received. |
|
INT_USER1 |
24 |
USER1 Interrupt. A user-defined interrupt. Set a bit in the interrupt mask to high and the interrupt will be called. |
|
INT_USER2 |
25 |
USER2 Interrupt. A user-defined interrupt. Set a bit in the interrupt mask to high and the interrupt will be called. |
|
INT_USER3 |
26 |
USER3 Interrupt. A user-defined interrupt. Set a bit in the interrupt mask to high and the interrupt will be called. |
|
INT_USER4 |
27 |
USER4 Interrupt. A user-defined interrupt. Set a bit in the interrupt mask to high and the interrupt will be called. |
|
INT_USER5 |
28 |
USER5 Interrupt. A user-defined interrupt. Set a bit in the interrupt mask to high and the interrupt will be called. |
|
INT_USER6 |
29 |
USER6 Interrupt. A user-defined interrupt. Set a bit in the interrupt mask to high and the interrupt will be called. |
|
INT_USER7 |
30 |
USER7 Interrupt. A user-defined interrupt. Set a bit in the interrupt mask to high and the interrupt will be called. |
|
INT_USER8 |
31 |
USER8 Interrupt. A user-defined interrupt. Set a bit in the interrupt mask to high and the interrupt will be called. |
The EnableInterrupt procedure names a procedure, proc, to be called when a given interrupt is requested. Only requests made after EnableInterrupt is called will result in the interrupt procedure being called.
Returns < 0 if there was an error in lParameter or the interrupt is already enabled. Returns 0 if the status is OK. Returns 1 if software emulation is done to check between commands to implement interrupts.
Some of the GPIB boards or Drivers (GPIBxxx.DLL) do not support interrupts or are not configured to support interrupts.
lParameter is set depending on the type of interrupt specified and should be 0 if not used.
proc should be a user-defined subroutine. The proc parameter used as the interrupt handler should be declared as having either one or no parameter. If one parameter is used, it must be declared as Val Long. The procedure should not return any value (Void). Two sample procedure declarations with this syntax are show below:
Procedure InterruptProc(lParam) : Void
lParam: Val Long
{
}
or
Procedure InterruptProc() : void
{
}
While the interrupt procedure executes, the associated interrupt is temporarily disabled, but other interrupts are unaffected. The interrupt request is cleared when the interrupt procedure returns.
When calling this procedure while executing Doit!/Loopit! a run-time error will occur (interrupts are disabled in Doit! mode).
Calling EnableInterrupt/DisableInterrupt or masking interrupts inside an interrupt subroutine will take place only on return. Re-enabling (Disable and Enable) of the current interrupt number handler during Interrupt sub is not allowed (only Disable is allowed). Re-enabling of other interrupt numbers is allowed.
Interrupts are serviced (called) according to their priority number. The interrupts priorities are:
TIMER1 (highest)
COM ports
GPIB boards
USER
ATEasy subroutines are not re-entrant; if an interrupt occurs inside a subroutine, that interrupt subroutine must not call that subroutine again.
Calling EnableInterrupt clears (zeros) the corresponding enInterrupt bit in the InterruptMask variable. Interrupts can be invoked by using the command:
SetInterruptMask (INT_USER1, True)
This command invokes the interrupt associated with INT_USER1 if enabled.
In general, interrupt procedures should execute quickly. Requests for the same interrupt during execution of the interrupt procedure will be lost. An interrupt procedure should not block itself for large periods of time waiting for user input or on some thread synchronization object.
In the following example, the interrupt subroutine TimeInt is called every second. This program segment terminates 10 seconds after the start if the TimeInt sub contains the statement i=i+1. Otherwise, the While/Endwhile loop is an endless loop.
i=0
EnableInterrupt (INT_TIMER1, 1000, TimeInt)
while i< 10
endwhile
print i
.
.
.
Procedure TimeInt() : Void
{
i=i+1
}