User`s guide

Operation Theory • 33

Operation Theory

The operation theory of the functions on PCI-9111 card is described in this

chapter. The functions include the A/D conversion, D/A conversion, Digital I/O

and counter / timer. The operation theory can help users understand how to

configure or to program the PCI-9111.

4.1 A/D Conversion

Before programming the PCI-9111 to perform any A/D conversions, you

should understand the following issues:

• A/D conversion procedure

• A/D signal source control

• A/D trigger source control

• A/D data transfer mode

• A/D Pre-trigger function

• Interrupt System (refer to section 4.2)

• A/D data format

Note: Because some A/D data transfer modes will utilizes the systems

interrupt resources, users also need a basic understanding the

interrupt system (section 4.2).