Справочник Пользователя для National Instruments NI 781xR

The NI 7811R has 160 bidirectional DIO lines and a one million gate 
FPGA.

The NI 7813R has 160 bidirectional DIO lines and a three million gate 
FPGA.

You can configure the NI 781xR DIO lines individually for either input or 
output. When the system powers on, the DIO lines are all high-impedance. 
To set another power-on state, you can configure the NI 781xR to load a VI 
when the system powers on. This VI then can then set the DIO lines to any 
power-on state.

The DIO signals on the NI 781xR connectors are DGND and DIO<0..39>. 
DIO<0..n> signals make up the DIO port, and DGND is the ground 
reference signal for the DIO port. The NI 781xR has four DIO connectors 
for a total of 160 DIO lines.

Refer to Figure B-1, 

, and Figure B-2, 

, for the connector locations and 

the I/O connector pin assignments on the NI 781xR.

The DIO lines on the NI 781xR are TTL compatible. When configured as 
inputs, they can receive signals from 5 V TTL, 3.3 V LVTTL, 5 V CMOS, 
and 3.3 V LVCMOS devices. When configured as outputs, they can send 
signals to 5 V TTL, 3.3 V LVTTL, and 3.3 V LVCMOS devices. Because 
the digital outputs provide a nominal output swing of 0 to 3.3 V 
(3.3 V TTL), the DIO lines cannot drive 5 V CMOS logic levels. To 
interface to 5 V CMOS devices, you must provide an external pull-up 
resistor to 5 V. This resistor pulls up the 3.3 V digital output from the 
NI 781xR to 5 V CMOS logic levels. Refer to Appendix A, 

, 

for detailed DIO specifications.