ICS Advent DIO24-P, Руководство по эксплуатации продукта

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Chapter 1: Introduction
Manual Number: 00431-024-14 Page 1-1
Chapter 1: Introduction
Description
The DIO24-P parallel digital I/O card provides 24 TTL/DTL compatible digital I/O lines, interrupt
input and enable lines and external connections to the IBM PC bus power supplies. It is a flexible
interface for parallel input/output devices such as instruments and displays and user contructed
systems and equipment.
24 digital I/O lines are provided through an 8255-5 programmable peripheral interface (PPI) IC.
These 24 lines are divided into three 8-bit ports, PA, PB, and PC. The PC port may also be further
divided into two 4-bit ports PC-Upper and PC-Lower. Each of the ports may be configured as an
input or an output by software control according to the contents of a write only register in the 8255.
Each port may be read as well as written to. In addition, the 8255 has other modes of operation that
allow unidirectional and bidirectional strobed I/O where the PC ports are used for control of data
transfer and interrupt generation, etc. Refer to the 8255 data sheet located at the back of this manual
for a complete technical description and summary of the various operating modes of the 8255.
Interrupt handling is via a tristate driver with separate enable (interrupt enable - active low). This
may be connected to any of the interrupt levels 2-7 available on the IBM PC bus by means of a plug
type jumper on the board. Handling of an interrupt is controlled by the 8259 interrupt controller on
the PC and this is set by the BIOS on system initialization to respond to their requirements and set up
corresponding interrupt handlers.
Power from the computer bus is available on the connector. Users should observe the current capac-
ity limits of the bus. 1A fuses are provided on all power outputs.
The board format is half-size and will fit in any full or half-length slot in a PC/XT/AT or compatible
computer running at any clock speed. Various termination boards are available such as the Indus-
trial Computer Source Model UTB-K.
Features
• 24 Channels of Digital Input/Output
• Four and Eight Bit Ports Independently Selectable for I/O
• Unidirectional/Bidirectional Strobed I/O
• Hysteresis on I/O Lines
• Interrupt Handling
Applications
• Security Systems, Energy Management
• Relay Monitoring and Control
• Parallel Data Transfer to PC
• Sensing Switches or Signals, or TTL, DTL, CMOS Logic
• Driving Indicator Lights or Recorders