ADLINK Technology NuDAQ PCI-9114DG, User Manual, Page: 45 / 95

Operation Theorem
•
33
The application software can use the “_9114_Get_Irq_Status” function to
distinguish which interrupt is inserted. After servicing an IRQ signal, users
should check if another IRQ is also asserted and then clear current IRQ to
allow the next IRQ occurring.
The two IRQs are named as INT1 and INT2. INT1 comes from AD EOC or the
FIFO half-full flag. INT2 comes from timer‘s pacer output only. The sources of
INT1 and INT2 are selective by the Interrupt Control (ISC) Register.
Because of dual interrupt system, for example, you can use FIFO half-full and
external interrupt at the same time if your software ISR can distinguish these
two events.
4.2.4 Interrupt Source Control
There are two bits to control the IRQ sources of INT1 and INT2. Refer to
section 4.9 for the details of the two bits. In addition, the PCI controller itself
can also control the use of the interrupt. For manipulating the interrupt system
more easily, we recommend you to use the function
_9114_INT_Source_Control to control the IRQ source so that you can disable
one or two of the IRQ sources.
Note that even you disable all the two IRQ sources without changing the initial
condition of the PCI controller, the PCI BIOS still assigns an IRQ level to the
PCI card and it will occupy the PC resource. It is not suggested to re-design
the initial condition of the PCI card by users‘ own application software. If users
want to disable the IRQ level, please use the software utility to change the
power on interrupt setting.
4.3 Isolation Digital Input
There are 16 isolation digital input signals. Every digital input signal is
connect to one photo isolator such that the signal is isolated from the ground
or the power plane of the hos t PC. The Figure 4.3 illustrates the single digital
input circuits.