ADLINK ACL-8112 Series - Manual (Page 49)

Operation Theory • 41
5
Operation Theory
The operation theory of the ACL-8112 card is described in this chapter. The
function description includes the A/D conversion, D/A conversion, digital I/O
and counter/timer. The operation theory can assist the user understand how
to manipulate or program the ACL-8112.
5.1 A/D Conversion
Before programming the ACL-8112 to perform an A/D conversion, you need
to understand the following issues:
• A/D conversion procedure
• A/D trigger mode
• A/D data transfer mode
• Signal Connection
A/D Conversion Procedure
An A/D conversion is initiated when a trigger source is triggered, the A/D
converter will start to convert the signal to a digital value. The ACL-8112
provides three trigger modes as discussed below.
During an A/D conversion, the DRDY bit of the A/D data register is cleared to
indicate the data is not ready. After a conversion is completed, the DRDY bit
will return a low (0) signal. This indicates users now can read the converted
data from the A/D data registers. Please refer to section 4.2 for the A/D data
format.