Introducing the cio-dio24/ctr3, Overview: cio-dio24/ctr3 features, Software features – Measurement Computing CIO-DIO24/CTR3 User Manual
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Chapter 1
Introducing the CIO-DIO24/CTR3
Overview: CIO-DIO24/CTR3 features
The CIO-DIO24/CTR3 has 24 digital I/O connections, one 82C55 parallel-interface chip. A 82C54 counter
chip provides three 16-bit down counters.
Each 82C55 chip controls 24 CMOS/TTL-compatible digital I/O pins. The 82C55 is configured as two 8-bit
ports and two 4-bit ports. Each port is programmable for input or output.
All I/O bits are set to input mode (high impedance) on power up and reset. If you are using the board to control
items that must be OFF on reset, install pull-down resistors. The board is equipped with open locations where
you can install SIP resistor networks for either pull-up or pull-down.
You can configure the counter 0 input to be clocked from an internal 10 MHz crystal oscillator or from an
external clock source.
All signals pass through a 37-pin connector.
The CIO-DIO24/CTR3 uses eight I/O addresses — the lower four are used by the 82C55 digital I/O chip, and
the upper four are used by the 82C54 counter/timer.
Software features
For information on the features of InstaCal and the other software included with your CIO-DIO24/CTR3, refer
to the Quick Start Guide that shipped with your device. The Quick Start Guide is also available in PDF at
.
for the latest software version.
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