Chapter 4 Theory Of Operation; Functional Overview; Figure 4-1. Lab-Pc+ Block Diagram - National Instruments Low-Cost Multifunction I/O Board for ISA Lab-PC+ User Manual

Chapter 4
Theory of Operation
This chapter contains a functional overview of the Lab-PC+ and explains the operation of each
functional unit making up the Lab-PC+. This chapter also explains the basic operation of the
Lab-PC+ circuitry.

Functional Overview

The block diagram in Figure 4-1 shows a functional overview of the Lab-PC+ board.
Data/
Address
PC I/O
Channel
Interface
Control
Signals
10 MHz
Oscillator
© National Instruments Corporation
16
FIFO
12
8253 8255A
Ctr/Timer Digital
Group A Interface
1-MHz
Timebase
10
2 MHz
5
Timebase

Figure 4-1. Lab-PC+ Block Diagram

4-1
12-Bit Pgm
A/D Gain
12
12
8
8
Input
Mux
Input
Mux
1
12-Bit
D/A
1
12-Bit
D/A
8253
Ctr/Timer
Group B
Lab-PC+ User Manual