Chapter 4 Theory of Operation
DAQCard-1200 User Manual 4-2 © National Instruments Corporation
The major components of the DAQCard-1200 are as follows:
• PC Card I/O channel interface circuitry
• Analog input circuitry
• Analog output circuitry
• Digital I/O 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 PC Card I/O channel interface circuitry consists of an address bus, a
data bus, interrupt lines, and several control and support signals. Figure 4-2
shows the components making up the DAQCard-1200 PC Card I/O channel
interface circuitry.
Figure 4-2. PC Card I/O Interface Circuitry Block Diagram
PC I/O Channel
Address Bus
Timing
Interface
Data
Buffers
Interrupt
Control
Address
Decoder
Control Lines
Data Bus
IRQ
Register Selects
Read and Write Signals
Internal Data Bus
Interrupt Requests
PCMCIA I/O Channel
Card
Information
Structure
PCMCIA
Control
Registers