Measurement Specialties manual Introducing the PCI-DIO24, PCI-DIO24 block diagram, Chapter

Chapter 1

Introducing the PCI-DIO24

This manual explains how to install, configure and use the PCI-DIO24 digital I/O board.

The PCI-DIO24 provides 24 lines of digital I/O. An on-board, industry standard 82C55 programmable peripheral interface chip provides the 24 digital I/O lines in three eight-bit ports (Port A, Port B, and Port C). Port C can be further divided into two four-bit ports (Port C-HI and Port C-LO). You can configure each port independently for either input or output. All 24 I/O lines are accessible through the board's 37-pin connector. The I/O pins of an 82C55 are bi-directional CMOS TTL level.

82C55 mode 1 or mode 2 operation

This user's guide provides information on I/O configuration of the 82C55 in mode 0. To use the 82C55 in modes 1 or 2, refer to the 82C55A CMOS Programmable Interface datasheet. This document is available on our web site at www.mccdaq.com/82C55.

PCI-DIO24 block diagram

PCI-DIO24 functions are illustrated in the block diagram shown here.

37-Pin I/O Connector

PORT A (7:0)

PORT B (7:0)

PORT CH (3:0)

PORT CL (3:0)

+5V

+12V

-12V

8255 DIO

PORT A

PORT B

PORT CH PORT CL

Control

				Controller FPGA and logic
Control
							Control
	Bus
						Registers
											IRQ INPUT
			Decode/Status						Interrupt		IRQ ENABLE
										Control
				Bus
			Timing
		Local Bus
	Boot
								BADR1
EEPROM					PCI
								BADR2
				Controller
								Interrupt

PCI BUS (5V, 32-bit, 33 MHZ)

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