Digital I/O,0 pages

Digital I/O, 24 or 96 Lines, 5 V TTL/CMOS
24 or 96-Line Digital I/O

NI 650x
• 24 or 96 digital input/output lines
• 5 V TTL/CMOS
• 2-wire handshaking capability
• Known power-up states
• NI-DAQ driver simplifies
configuration and measurements

Operating Systems

Models

Recommended Software

• NI PCI-6503
• NI DAQCard-DIO-24
• NI PC-DIO-24
• NI PCI-DIO-96
• NI PXI-6508
• NI PC-DIO-96

• LabVIEW
• LabWindows/CVI
• Measurement Studio

• Windows 2000/NT/XP
• Real-time performance with
LabVIEW (see page 134)
• Others such as Linux and
Mac OS X (see page 187)

Other Compatible Software
• Visual Basic
• C/C++, C#

Driver Software (included)
• NI-DAQ 7

Family
NI 6503

1Handshaking

Digital I/O Lines
24

Device Type
Software timed

Logic Level
5 V TTL/CMOS

Isolation
–

Handshaking I/O
✓1

8255 Chipset
✓

Change Notification
–

Pattern Matching
✓

96
–

Software timed

5 V TTL/CMOS

–
–

✓1
✓1

✓
✓

–
–

✓
✓

supplied by the 8255; only one handshaking mode is available.

Table 1. NI 650x Specifications Overview (See page 385 for detailed specifications.)

Overview and Applications

Digital I/O Connector

NI 6503 devices are 24-bit parallel DIO interfaces for PCI, PCMCIA,
and ISA. NI 6508 devices offer 96-bit parallel DIO interfaces for PCI,
PXI, and ISA. All NI 650x devices are designed for 5 V TTL/CMOS
I/O signals.

Digital connectors for the NI 650x devices are described in Table 2.
The eight bits in Port A of each PPI are at xPA7 through xPA0 on the
digital I/O connector where x represents which PPI is being used. Ports B
and C are at xPB7 through xPB0 and xPC7 through xPC0, respectively.
Each port is programmed to be input or output. Power from the
computer I/O channel is also available on the DIO connector. See page
381 to learn more about connectivity solutions, including direct
connectors, electromechanical relay devices, and other signal
conditioning solutions.

Hardware
82C55 Parallel Port Interfaces
NI 650x devices use 82C55 Parallel Port Interfaces (PPIs). NI 6503
devices contain one PPI, and the NI 6508 devices contain four. Each
PPI controls 24 bits of DIO and has three 8-bit ports (A, B, and C). You
can configure each port as either input or output. Ports A and B are
always used for digital data I/O, while port C can be configured for
digital data I/O, control, status, or handshake signals.

Device
PCI-6503
PC-DIO-24
DAQCard-DIO-24
NI 6508

Data Acquisition and
Signal Conditioning

NI 6508

Bus
PCI
PCMCIA
ISA
PCI
PXI
ISA

Connector
50-pin, shown in Figure 3
27-pin; cable adapts it to the 50-pin connector shown in Figure 3
100 pin; shown in Figure 2

Table 2. NI 650x Connector Overview

Digital I/O Power-Up State Selection
You can power up the PCI-6503, PC-DIO-24, PC-DIO-96, and
PXI-6508 DIO lines in a user-defined state – either high or low. On
these devices, each line is connected to a 100 kΩ resistor, and you can
use a jumper to select whether the lines of the device power up in
the high or low state. The DAQCard-DIO-24 and PCI-DIO-96 have
100 kΩ resistors that always pull high.

National Instruments • Tel: (800) 433-3488 • Fax: (512) 683-9300 • info@ni.com • ni.com

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