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PCI Express Digital I/O Cards with Counters and COS Detection


  • 24 high-current DIO lines
  • Three optional 82C54 Counter / Timers
  • IRQ generation from Port C bit 3, and Counter A2 ("C" models) and/or Change-of-State (COS) Detection ("S" models)
  • DIO lines buffered
  • Four and eight bit ports independently selectable for inputs or outputs
  • Software selectable 10k ohm Pull-up/Pulldown resistors on DIO lines
  • Jumper selectable VCCIO (5V, 3.3V, 2.5V,1.8V)
  • VCCIO voltage available to the user via 0.5A resettable fuse
  • Designed, made, supported, and manufactured in the USA


  • Extended temperature operation (-40° to +85°C)
  • RoHS compliant version
  • Support for Wind River VxWorks (call for ordering information)

This product is a x1 lane PCIe DIO board available in four models ranging from basic DIO to advanced COS detection and Counter/Timer capabilities. The card emulates an 8255 compatible chip, providing 24 DIO lines. The DIO lines are grouped into three 8-bit ports: A, B, and C. Each 8-bit port is configured via software to function as either inputs or outputs. Port C can be further broken into two 4-bit nybbles via software and configured as either inputs or outputs.

Each DIO line is buffered and capable of up to 32mA source/sink. The VCCIO logic level is globally configured via jumper selection as 5V, 3.3V, 2.5V or 1.8V. Also, ports A, B, C low nybble, and C high nybble are individually software selected as pull-up or pull-down through 10kΩ resistor networks. The last configured pull-up/down state is stored in on-board non-volatile memory and automatically applied at the next power up. The board is shipped factory default as pulled-up.

The card is 6.6 inches in length and 4.2 inches seated height. I/O wiring connections for this board are via a male 37-pin D-sub connector. A ribbon cable can be used to connect this card to termination panels.



The card is supported for use in most operating systems and includes a free DOS, Linux, and Windows XP -> 10, both 32 & 64 bit compatible software package. This package contains sample programs and source code in Visual Basic, Delphi, and Visual C++ for Windows. Also provided is a graphical setup program in Windows. Linux support includes installation files and basic samples for programming from user level via an open source kernel driver. Third party support includes a Windows standard DLL interface usable from the most popular application programs. Embedded OS support includes Windows Xpe, WES7, vxWorks, etc.

Available Reference Manuals

Available Software Downloads

Available Datasheets

Drivers and Downloads

Full list of available Downloads: Software Packages, Drivers, Manuals, and other documents

Custom Software

ACCES also offers Custom Software Services for our products. Our prices are unbelievably low, often as inexpensive as free! If you need something tweaked to support your needs, or an entire enterprise application developed from scratch, it is definitely worth your time to inquire with us, first.

Further information about available ACCES Software:

Redistributing Windows Drivers
A list of ACCES drivers and the files that compose them under different versions of Windows, so you can easily redistribute ACCES cards and drivers.


ACCES has successfully partnered with Wind River to bring our entire line of PCI and PCI Express DAQ cards to VxWorks 7!

VxWorks 7 VxBus Gen 2 drivers, with easy-to-use API-libraries, are available for this product, including full source and sample code.

Designed to be compatible with our AIOWDM.dll Windows driver & API, this kernel module adds zero% CPU-cycle overhead to your VxWorks runtimes while allowing the lowest-latency hardware register access possible.

You can find more information about our VxWorks libraries and services on our Wind River Silver Partner page.

Digital I/O

Logic Levels

  • 5 Volt
    • Input Low ≤ 1.5V, ≤2µA
    • Input High ≥3.5V, ≤2µA
    • Output Low ≤ 0.55V @ 32mA
    • Output High ≥3.8V @ 32mA
  • 3.3V
    • Input Low ≤ 0.8V, ≤2µA
    • Input High ≥2.0V, ≤2µA
    • Output Low ≤ 0.55V @ 24mA
    • Output High ≥2.4V @ 24mA
  • 2.5V
    • Input Low ≤ 0.7V, ≤2µA
    • Input High ≥1.7V, ≤2µA
    • Output Low ≤ 0.3V @ 8mA
    • Output High ≥1.9V @ 8mA
  • 1.8V
    • Input Low ≤ 0.63V, ≤2µA
    • Input High ≥1.17V, ≤2µA
    • Output Low ≤ 0.45V @ 4mA
    • Output High ≥1.2V @ 4mA

Counter / Timers

Number / Type Three 82C54 programmable counters
Counter size 16-bit
Logic level VCCIO
On-board clock 1MHz
Clock Pulse Width High - 30ns (min) Low - 40ns (min)


Operating Temperature 0° to 70°C, optional -40° to +85°C
Storage Temperature -55° to +150°C
Humidity 5% to 90% RH, w/o condensation
Card Dimensions Length - 6.6"; Height - 4.2" seated

Regulatory Compliance

  • This product is in full compliance with CE requirements.

OEM and volume pricing available, please call us.  

ModelPrice (USD)

Ordering Guide
PCIe-DIO-24DPCI Express 24 channel digital I/O card
PCIe-DIO-24DSPCI Express 24 channel digital I/O card with change of state detection
PCIe-DIO-24DCPCI Express 24 channel digital I/O card with counter/timers
PCIe-DIO-24DCSPCI Express 24 channel digital I/O card with 82C54 counter/timers and change of state detection
STB-37DIN-rail mountable screw terminal board for 37-pin connector $39
CAB37-18Ribbon cable, 37-pin connectors on each end, 18 inches long $25
CAB37-xxAs above except “xx” equals length in inches (add $2 per Ft over 18") $25
DIN-SNAP-66-inch SNAP-TRACK with two clips for mounting one STB-37 on a DIN rail $15
ADAP37Screw terminal adaptor for direct mounting to 37-pin connector $40
STA-37Screw terminal assembly with two 37-pin D connectors and breadboard area $79
T-BOXSteel enclosure with powder coated finish, use to mount STA-37 to panel $45
Model Options:
-RoHSRoHS compliant version
-T Extended temperature (-40°C to +85°C)

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