Digital i/o, Timing i/o – National Instruments Low-Cost Multifunction I/O Board for ISA Lab-PC+ User Manual

Page 86

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Appendix A

Specifications

© National Instruments Corporation

A-5

Lab-PC+ User Manual

Differential nonlinearity (DNL) in a D/A system is a measure of deviation of code width from
1 LSB. In this case, code width is the difference between the analog values produced by
consecutive digital codes. A specification of

±

1 LSB differential nonlinearity ensures that the

code width is always greater than 0 LSBs (guaranteeing monotonicity) and is always less than
2 LSBs.

Digital I/O

Number of channels ......................................

24

Compatibility ................................................

TTL

Digital logic levels ........................................

Level

Min

Max

Input low voltage

Input high voltage

Input low current

(V

in

= 0.8 V)

Input high current

(V

in

= 2.2 V)

-0.3 V

2.2 V

-

-

0.8 V
5.3 V

-1.0

µ

A

1.0

µ

A

Output low voltage

(I

out

= 2.5 mA)

Output high voltage

(I

out

= -2.5 mA)

-

3.7 V

0.4 V

-

Darlington drive output current (Ports B and C only)

(R

EXT

= 700

, V

EXT

= 1.7 V)................

±

2.5 mA min,

±

4 mA max

Handshaking..................................................

3-wire (requires 1 port)

Power-on state ...............................................

Configured as input

Data transfers ................................................

Interrupt, programmed I/O

Timing I/O

Number of channels ......................................

3

counter/timers

Resolution .....................................................

16

bits

Compatibility ................................................

TTL, gate and source pulled high with

4.7 k

resistors

Base clocks available ....................................

2 MHz

Base clock accuracy ......................................

0.01%

Max source frequency ...................................

8 MHz

Min source pulse duration .............................

60 ns

Min gate pulse duration.................................

50 ns

Data transfers ................................................

Programmed

I/O

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