Справочник Пользователя для National Instruments PC-DIO-24

                                                                                                          

 

This chapter contains a functional overview of the PC-DIO-24 board and explains the operation
of each functional unit making up the PC-DIO-24.

The block diagram in Figure 3-1 illustrates the key functional components of the PC-DIO-24
board.

I/O Connector

Interrupt

Control

Circuitry

82C55A

PPI

PC I/O

 Channel

Control

Circuitry

Address

Decoder

Bus

Transceivers

PA

PB

PC

/

8

/

8

/

8

PC3

PC0

+5 V

PC I/O Channel

1 A Fuse

Figure 3-1.  PC-DIO-24 Block Diagram

The PC I/O Channel consists of an address bus, a data bus, interrupt lines, and several control
and support signals.  Control and data transfers to the system microprocessor are asynchronous.