Appendix B
Register-Level Programming — 82C53 Programmable Interval Timer (PCI-DIO-96, PXI-6508 Only)
©
National Instruments Corporation
B-3
PCI-DIO-96/PXI-6508/PCI-6503 User Manual
The block diagram in Figure B-1 illustrates the interrupt control circuitry.
Figure B-1.
Interrupt Control Circuitry Block Diagram
CLK0
GATE0
OUT0
CLK1
GATE1
OUT1
CLK2
GATE2
OUT2
2 MHz
+5 V
+5 V
82C55A
PPI A
82C55A
PPI B
82C55A
PPI D
82C55A
PPI C
PCI
Interrupt
PC3
PC0
PC3
PC0
PC3
PC0
82C53
Counter/Timer
PC3
PC0
Interrupt
Control
Circuitry
Interrupt Control Registers
PCI-DIO-96/PXI-6508 Only