Chapter 1 Getting to Know Your NI 6509/651x/6520/6521/6528 Device
Static DIO Register-Level Programmer Manual
1-2
ni.com
Caution
Using your NI 6509/651
x
/6520/6521/6528 device in a way inconsistent with the
directions in the
Digital IO Help
can lead to equipment damage or injury. National
Instruments is
not
liable for damage or injuries resulting from incorrect use.
Using Your NI 6509/651
x
/6520/6521/6528
•
PCI interface
•
General operation registers
PCI Interface
The NI 6509/651
x
/6520/6521/6528 use the PCI MITE Application-Specific Integrated
Circuit (ASIC) to communicate with the PCI or PXI bus. National Instruments designed this
ASIC specifically for data acquisition. Before register-level programming the
NI 6509/651
x
/6520/6521/6528 device, you must initialize the PCI interface as described in
Chapter 3,
General Operation Registers
Initialize the PCI interface before using the general operation registers. Read the ID Register,
one of the general operation registers, to verify the PCI interface is initialized properly. For
more information on the ID Register, refer to the
section in Chapter 2,
.
The general operation registers include the IO Port Data registers and corresponding IO Select
registers for reading and writing data. There are also registers for controlling digital filtering,
change detection, the watchdog timer, RTSI output, and PXI synchronization. With the final
set of registers, you can read and reset the status of your device.
The general operation registers are organized into two groups—recurring and non-recurring
registers. Each port has a sequence of recurring registers for Data, IO Select, and other
port-specific features. This same set of registers is repeated for each port but incremented
0x10 times the port number above the base address. The non-recurring registers affect the
entire board and have set addresses.
