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24-Channel Digital I/O with Digital Integration Features on PCI Express Mini Card


  • With Digital Integration Features!
    Outputs with pulse/train / PWM / frequency / and Quadrature generation, Inputs with digital filtering and flexible measurement of pulse duration, frequency, and event counting, IRQ generation and more.
  • PCI Express Mini Card (mPCIe) Type F1, with latching I/O connectors
  • 24 high-current LVTTL DIO lines (24ma source/sink)
  • Change-of-State (COS) detection IRQ generation
  • 10k ohm pull-up resistors
  • Four and eight bit ports independently software selectable for use as inputs or outputs
  • All signals brought out to optional panel-mountable 37-pin male D-Sub connector
  • RoHS standard
  • Available soon in M.2 form!
  • Designed, made, supported, and manufactured in the USA


  • Industrial operating temperature (-40°C to +85°C)
  • TTL signaling with user supplied VCCIO (5V)
  • Support for Wind River VxWorks (call for ordering information)

The mPCIe-DIO-24A is a type F1 PCI Express Mini Card (mPCIe) and optional cable assembly (D-Sub 37-pin Male connector) designed to be easily panel-mounted in any application environment. It uses the high speed PCI Express bus to transfer digital data to and from the card. The digital I/O is compatible with 8255 PPI chips making it easy to program. This also allows for simple and trouble-free migration from other ACCES PCI and PCI Express digital I/O cards, but also provides for advanced features enabled by the onboard FPGA logic.

The card provides three 8-bit I/O ports designated A, B and C. Port C can be further divided into two 4-bit nybbles. Each port can be programmed as inputs or outputs. Change of State (COS) detection and interrupt capabilities are designed to relieve software from polling routines that can consume valuable processing time. Each port can be programmed for detecting state changes on their lines, in which any changes of the enabled port's bits (low-to-high or high-to-low) will generate an IRQ. An ISR (interrupt service routine) then determines which bit changed state and clears the interrupt.


DigitalFeatures (read as "Digital Integration Features") are a new family of features available for applicable models of ACCES' PCI Express (PCIe) and PCI Express Mini Card (mPCIe) Digital I/O product lines.

All the cards share features such as memory mapped registers for low-latency operation. Output channels support pulse/train / PWM / frequency / and quadrature generation. Inputs channels support flexible measurement of pulse duration, frequency, and event counting, with optional debouncing, IRQ generation, and more.


The mPCIe-DIO-24A is excellent for use in applications sensing inputs such as switch closures, TTL, LVTTL, CMOS logic and controlling external relays, driving indicator lights, and more. The mPCIe-DIO-24A can be used in the following markets.

  • Process Monitoring
  • Manufacturing/Production Test
  • Machine Control
  • Monitoring and Control
  • Security Systems, Energy Management
  • Industrial Automation
  • Factory Automation
  • Laboratory Automation
  • Embedded OEM

Special Order

Please contact ACCES with your precise requirement. Examples of special orders would be pull-down resistors, conformal coating, a TTL version with user supplied 5VDC VCCIO, custom software or product labeling, and more. We will work with you to provide exactly what is required.

Accessories and Connections

Available accessories include a 40-pin to male DB-37 cable and screw terminal boards for quick and easy connectivity. I/O on the card is accessed via a 40-pin latching Molex connector. Alternately, custom hardware cables and/or interfaces can be produced to fit your specific application requirement.


The card is supported for use in most operating systems and includes a free DOS, Linux , and Windows 2000/XP/2003/Vista/7/8/10 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, and includes LabVIEW 8.5+ VIs. Embedded OS support includes Windows XPe, WES7, WES8, vxWorks, etc. Full register-level documentation of all features ensures easy compatibility in any application environment.

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.

PC Interface

  • PCI Express Mini Card: Type F1 "Full Length" V1.2

Digital Input / Output Interface

  • Digital Bits: 24
  • Compatibility: 8255 Mode 0
  • Performance: 1 μs per 32-bit transaction max, ∼3.5μs in Windows
  • Digital Inputs
    • Logic High: 2.0V to VCCIO (3.3VDC, 5VDC tolerant)
    • Logic Low 0V to 0.8V
  • Digital Outputs (Standard Version)
    • Logic High: 2.0V (min) 24mA source
    • Logic Low: 0.55V (max) 24mA sink
    • Power Output: +3.3 VDC via 0.5A polyfuse (resetting)
  • TTL with user VCCIO Digital Outputs (-TTL option)
    • 1.65V to 5.5V: At DB37M, via polyfuse
    • Logic High: 3.8V (min) 32ma UVCCIO = 4.5V
    • Logic Low: 0.55V (max) 32ma UVCCIO = 4.5V


  • Input features
    • Change-of-State IRQs ×24: All input bits
      Compatible with all ACCES PCI and Express DIO CoS products
    • Event Counting w/IRQ ×16: Bits 0-7 & 16-23, only
      Count up to 255 events of enabled types, 8-bit IRQ threshold per bit
    • Debounced Inputs ×16: Bits 0-7 & 16-23, only
      Enabled per-bit, Global configuration between ms- and µs-scale filtering
    • Pulse Measurement ×16: Bits 0-7 & 16-23, only
      Measured using 8ns 16-bit clock, Narrowest pulse 8ns, longest 524.28ms
    • Frequency Measurement ×16: Bits 0-7 & 16-23, only
      Measured using 8ns 32-bit clock, Fastest frequency 62.5MHz
    • Quadrature Counter ×1: Bits 20 & 21 only (A/B)
      32-bit 2's complement counter, up to 62.5MHz, ×1 mode only, Optional Index input (Z) on bit 22
  • Output features
    • Motor Control ×1: Bits 16 & 17 only (A/B)
      32-bit 2's complement (bidirectional) quadrature output, between 62.5MHz and 119.2Hz
    • Pulse Generation ×8: Bits 8-15 only
      Generate a high or low pulse using 8ns resolution, 16ns to 524.280ms duration
    • Pulse Train Generation ×8: Bits 8-15 only
      Generate between 2 and 255 pulses (as above) with 8ns to 524.280ms between them
    • PWM Generation ×8: Bits 8-15 only
      Specify high- and low-side pulse durations with 8ns resolution from 16ns to 524.280ms


  • Temperature
    • Operating: 0°C to 70°C (order -T option for industrial temperature -40°C to 85°C)
    • Storage: -65°C to 150°C
  • Humidity: 5% to 95%, non-condensing
  • Power required: +3.3VDC @ 330ma (typical)


  • Weight:6.2 grams (plus 22.2g for the cable)
  • Size
    • Length: 50.95mm (2.006″)
    • Width: 30.00mm (1.181″)
  • I/O connector
    • On-card: Molex 501190-4017 40-pin latching
    • Mating: Molex 501189-4010
    • On cable: Male, D-Sub Miniature, 37-pin
    • Mating:Female, D-Sub Miniature, 37-pin

Regulatory Compliance

  • This product is designed to be in full compliance with CE requirements.

OEM and volume pricing available, please call us.

mPCIe-DIO-24A24 Digital I/O with Change-of-State (COS) IRQ PCI Express Mini Card
CAB-mPCIe-DB37M40-pin to DB37-pin male cable $29
CAB-mPCIe-40P40-pin to 40-pin discreet cable $29
mPCIe-HDW-KIT22mm mounting hardware $1
mPCIe-HDW-KIT2.52.5mm mounting hardware $1
ADAP37Screw terminal adaptor for use with 37-pin male connector $40
STB-37DIN-rail mountable screw terminal board for 37-pin connector $39
STA-3737-pin screw terminal board $79
CAB37-18Ribbon cable, female 37-pin connectors on each end, 18" $25
CAB37-36Ribbon cable, female 37-pin connectors on each end, 36" $29
CAB37MF-36Ribbon cable, male to female 37-pin connectors, 36" $29
CAB37FM-18Ribbon cable, male to female 37-pin connectors, 18" $29
Model Options (call for pricing)
-TExtended temperature operation (-40° to +85°C)
-TTLTTL signaling with user supplied VCCIO (+5V)
Acquisition, Control, Communication: Engineering and Systems