Chapter 4
Theory of Operation
DAQCard-1200 User Manual
4-2
ni.com
The major components of the DAQCard-1200 are as follows:
•
PC Card I/O channel interface circuitry
•
AI circuitry
•
AO circuitry
•
DIO circuitry
•
Timing circuitry
•
Calibration circuitry
The internal data and control buses interconnect the components. The rest
of the chapter explains the theory of operation of each of the
DAQCard-1200 components.
PC Card I/O Channel Interface Circuitry
The DAQCard-1200 PC Card I/O channel interface circuitry is shown in
Figure 4-2 and consists of an address bus, a data bus, interrupt lines, and
several control and support signals.
Figure 4-2.
PC Card I/O Interface Circuitry Block Diagram
PCMCIA
I/O
Channel
Address Bus
Control Lines
Data Bus
IRQ
Timing
Interface
Data
Buffers
Interrupt
Control
Address
Decoder
Card
Information
PCMCIA
Control
Register Selects
Read and Write Signals
Internal Data Bus
Interrupt Requests
