National Instruments DAQCard-1200 - Manual (Page 37)

Chapter 3 Signal Connections
© National Instruments Corporation 3-15 DAQCard-1200 User Manual
Digital I/O Signal Connections
Caution The DAQCard-1200 DIO lines are not pulled up or pulled down. If you are using
these lines as digital outputs, add 10 k
Ω Ω Ω Ω
resistors to +5 V or DGND (depending on
your application) to the DIO line(s) you are using.
Pins 13 through 37 of the front connector are digital I/O signal pins.
Digital I/O on the DAQCard-1200 uses the 82C55A integrated circuit.
The 82C55A is a general-purpose peripheral interface containing
24 programmable I/O pins. These pins represent the three 8-bit ports
(PA, PB, and PC) of the 82C55A.
Pins 14 through 21 are connected to the digital lines PA<0..7> for
digital I/O port A. Pins 22 through 29 are connected to the digital lines
PB<0..7> for digital I/O port B. Pins 30 through 37 are connected to the
digital lines PC<0..7> for digital I/O port C. Pin 13, DGND, is the digital
ground pin for all three digital I/O ports. Refer to Appendix A,
Specifications , for signal voltage and current specifications.
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