General Purpose Analog and Digital I/O Module for PC/104 Bus

GPIO-104 GPIO-104

  • Stock Number:

  • 100-7602

  • Budgetary Pricing:

  • $293.00 / 001 - 009
  • $278.35 / 010 - 024
  • $263.70 / 025 - 049
  • $249.05 / 050 - 099
  • $234.40 / 100 - 249
  • Contact us for More Quantity Discounts

  • Typical Lead-Time:

  • Stock - 2wks

  • get quote


The GPIO-104 is an 8-bit analog and digital input/output module designed to satisfy a broad range of applications. Its generous assortment of functions and capabilities will, in many instances, make the GPIO-104 the only peripheral module required. It conforms to the PC/104 standard, operates on a single +5V power supply, and uses a single 50-Position IDC header for all I/O connections.

Analog Inputs:

Eight 12-bit single-ended analog inputs are provided, each with software programmable input ranges of ±10V, ±5V, +5V, +10V. This capability effectively increases the dynamic range to 14-bits when employing software range-switching techniques. Input protection handles applied voltages up to ±16.5V and continues to function even when power is off. In addition, a fault condition on any input channel will not affect the operation of the remaining channels. A special feature of the analog-to-digital converter is its ability to allow the separate acquisition and conversion times be individually controlled by the user's software or automatically sequenced by the GPIO-104 hardware. Overall timing is precisely maintained by a crystal oscillator. Conversions are initiated by writing a control byte to the converter which configures the input channel and range along with other parameters. The host can determine when the conversion is complete using one of three methods: by simply waiting longer than the conversion time, by polling a status flag or by having the status flag interrupt the host when it becomes set. Throughput up to 100ksps is possible limited only by the speed of the host computer. The resulting 12-bit value is read as two bytes in an 8+4 format.

Analog Outputs:

The four 12-bit analog outputs are individually hardware programmable to provide one of three popular output ranges: ±5V, +5V, +10V. An on-board DC/DC converter enables the bipolar and +10V ranges to be achieved without requiring any additional power supplies. The GPIO-104 includes the capability of having all the outputs update simultaneously by means of a single software write command. Those pre-loaded with new data change, while the remaining channels maintain their previous output voltages glitch-free. This feature is particularly useful in applications which can not tolerate phasing errors between the outputs. The 12-bit data is loaded into the DACs using an 8+4 bit format.

Digital I/O:

An industry standard 82C55 Programmable Peripheral Interface chip provides 24 digital channels across three 8-bit ports. This device offers very flexible configuration, including software programmable port directions and strobed handshaking. Each channel has a 10k pullup resistor and defaults to input mode during system reset.


  • Analog I/O and Digital I/O in a single low-cost module
  • Eight 12-bit multi-range analog inputs (±10V, ±5V, +5V, +10V)
  • Up to 100ksps throughput, self-timed or user-controlled acquisition
  • Four 12-bit multi-range analog outputs (±5V, +5V, +10V)
  • 24 digital Input/Output channels using familiar 82C55 chip
  • Interrupts fully support sharing and access to all PC/104 bus IRQs
  • Single +5 volt power requirement



Analog Inputs
General:One MAX197 DAS chip provides eight multi-range single-ended analog input channels
A/D Resolution:12-bit (1 in 4096 of full-scale), 14-bit effective dynamic range using software range-switching techniques
Input Range:Each channel has software programmable input range: ±10V, ±5V, +5V or +10V
Overvoltage:±16.5V protection. A fault condition on any channel will not affect readings on other channels
Sampling:100,000 samples/sec max. (Host dependent), self-timed or user controlled acquisition
Analog Outputs
General:Two AD7237 chips provide four multi-range analog output channels. Supports simultaneous updates
D/A Resolution:12-bit (1 in 4096 of full scale)
Output Ranges:Each channel has jumper selectable output range: ±5V, +5V or +10V
Output Current:±5mA max. per output
Settling Time:8μs max. to within ±1LSB of final value
Relative Accuracy:±1LSB
Nonlinearity:Less than ±1LSB, guaranteed monotonic
Digital I/O
General:One 82C55 chip provides 24 digital I/O channels across three 8-Bit ports. Supports modes 0, 1 and 2
Compatibility:TTL/CMOS levels. Each channel is capable of sourcing or sinking 2.5mA, 10k pull-up on each channel
Addressing:8-bit PC/104 bus. Jumper selectable for any 16 byte block in hosts I/O map, 0x00016 through 0x3f016
Interrupt:One interrupt, Jumper selectable IRQ 3,4,5,6,7,9, (10,11,12,14,15)* or Disable. Supports sharing. Used by Analog-to-Digital converter and positive level sensitive external interrupt. * Optional 20-Position J2/P2 stack-through connector required for upper IRQs
Power Requirement:+5Vdc ±5% @ 340mA typical, unloaded outputs
Dimensions:PC/104 compliant, 3.55"W x 3.775"L. 8-bit stack-through, optional 16-bit stack-through
Environmental:Operating temperature: 0°C to 65°C (Standard) Non-condensing relative humidity: 5% to 95%
Product Origin:Designed, Engineered, and Assembled in U.S.A. by SCIDYNE Corporation using domestic and foreign components.

You may also be interested in these products