ADLINK Technology NuDAQ ACL-8216, Руководство пользователя

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Registers Format
•
29
Base + 1 Counter 1 Register ( R/W)
Base + 2 Counter 2 Register ( R/W)
Base + 3 8254 CONTROL BYTE
4
O p e r a t i o n T h e o r e m
The operation theorem of the functions on ACL-8216 card is
described in this chapter. These functions include the A/D
conversion, D/A conversion, digital I/O and counter / timer. The
operation theorem can help you to understand how to manipulate or
to program the ACL-8216.
4.1 A/D Conversion
Before programming the ACL-8216 to perform the A/D conversion,
you should understand the following issues:
•
A/D conversion procedure
•
A/D trigger mode
•
A/D data transfer mode
•
Signal connection
4.1.1 A/D Conversion Procedure
The A/D conversion is started by a trigger source, then the A/D
converter will start to convert the signal to a digital value. The ACL-
8216 provides three trigger modes, see section 5 .1.2.
While A/D conversion, the DRDY bit in Status Control register is
cleared to indicate that the data is not ready. After conversion being
completed, the
DRDY bit will return to low(0) level. It means users