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Appendix A Specifications
PCI-4451/4452 User Manual A-8
©
National Instruments Corporation
Digital logic levels
Power-on state ........................................Input (High-Z)
Data transfers..........................................Programmed I/O
Timing I/O
Number of channels................................2 up/down counter/timers,
1 frequency scaler
Resolution
Counter/timers.................................24 bits
Frequency scaler..............................4 bits
Compatibility..........................................TTL/CMOS
Base clocks available
Counter/timers.................................20 MHz, 100 kHz
Frequency scaler..............................10 MHz, 100 kHz
Base clock accuracy................................±0.01%
Max source frequency.............................20 MHz
Min source pulse duration .....................10 ns, edge-detect mode
Min gate pulse duration .........................10 ns, edge-detect mode
Data transfers..........................................DMA, interrupts,
programmed I/O
Level Min Max
Input low voltage
Input high voltage
Input low current (V
in
= 0 V)
Input high current (V
in
= 5 V)
0.0 V
2.0 V
—
—
0.8 V
5.0 V
−320 µA
10 µA
Output low voltage (I
OL
= 24 mA)
Output high voltage (I
OH
= 13 mA)
—
4.35 V
0.4 V
—
User.book Page 8 Tuesday, April 14, 1998 10:20 AM