PC/104 48-ch. Digital I/O

  • Description
  • Specifications
  • Ordering Guide

This module is identical to our OMM-XT but it is without the counter/timer and interrupt circuitry. This board still has the quality and attention to detail of our other modules, such as: 10K Ohm pull-up resistors on all I/O lines; all ports reset to 0 on power-up or system reset; connector pinouts compatible with our other digital I/O boards; and free software.

The 48 digital I/O lines on OMM-DIO-XT are based on 2 82C55 ICs. They can be programmed for input or output in groups of 8 lines. Direct as well as strobed (latched) I/O modes are supported, and all I/O lines are connected to 10K Ohm pull-up resistors.

Chip 82C55A (qty. 2)
Number of I/O Lines 48, TTL/CMOS Compatible
Direction Programmable in groups of 4 and 8
Input Voltage Low: -0.5V min, 0.8V max
High: 2.0V min, 5.5V max
Output Voltage Low: 0.0V min, 0.4V max
3.0V min, Vcc -0.4V max
Output Current ±2.5mA max, each line
Pullup Resistors 10KOhms all input lines
Power Supply +5V ±5% @ 120mA typical all outputs open
Operating Temperature -40 to +85°C
Model Description
OMM-DIO-XT PC/104 48-ch. Digital I/O