Low-Cost Digital I/O Device for USB

Overview

The National Instruments USB-6501 is a portable digital I/O device,

providing reliable data acquisition and control at a low price. With

plug-and-play USB connectivity, the NI USB-6501 is simple enough

for home/academic applications but robust and versatile enough for

laboratory/industrial applications. The board-only version is ideal

for embedded OEM applications.

Hardware

The USB-6501 is a full-speed USB device that provides 24 DIO lines and

a 32-bit counter. The 24 digital lines are arranged in three ports: P0.<0..7>,

P1.<0..7>, and P2.<0..7>. P2.7 can also function as a 32-bit counter. You

can individually program each of the USB-6501 DIO lines as a DI or DO

line and use the DIO lines to monitor or control digital signals. All

samples of the DI lines and updates of the DO lines are software-timed.

The default configuration of the USB-6501 DIO ports is open-drain, for

5 V operation with an onboard 4.7 kΩ pull-up resistor. You can add an

external, user-provided, pull-up resistor to increase the source current

drive up to 8.5 mA per line.

Each DIO signal is protected against overvoltage, undervoltage, and

overcurrent conditions, as well as ESD events. At system startup and

reset, the hardware sets all DIO lines to high-impedance inputs.

Product

Bus

Digital I/O

Lines

Counter/

Timers

Current

Drive

Logic Level

Industrial

Feature Set

NI 6501

USB

24

1

8.5 mA

5 V TTL /

CMOS

–

Table 1. USB-6501 Features

• Small, portable digital I/O device

• 24 digital I/O lines, one 32-bit counter

• Overvoltage protection, 8.5 mA

current drive

• Full-speed USB (12 Mb/s) bus interface

• Built-in screw terminals with removable

connectors for easier connectivity

• OEM version available with 34-pin IDC

mass termination connectivity

Operating Systems

• Windows Vista/XP/2000

Recommended Software

• LabVIEW

Measurement Services

Software (included)

• NI-DAQmx driver software

• Measurement & Automation Explorer

configuration utility

NI-DAQmx Base.

NI USB-6501

Terminal

Signal

1

GND

2

+5 V

3

P1.7

4

P1.6

5

P1.5

6

P1.4

7

GND

8

GND

9

P2.7

10

P2.6

11

P2.5

12

P2.4

13

P2.3

14

P2.2

15

P2.1

16

P2.0

Terminal

Signal

17

P0.0

18

P0.1

19

P0.2

20

P0.3

21

P0.4

22

P0.5

23

P0.6

24

P0.7

25

GND

26

GND

27

P1.0

28

P1.1

29

P1.2

30

P1.3

31

+5 V

32

GND

Figure 1. USB-6501 Pinout