Data Translation DT330 Series, Руководство пользователя

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Chapter 5
58
Digital I/O Features
This section describes the following digital I/O features of the DT330 Series boards:
• Digital I/O lines
• Resolution
• Interrupts
• Operation modes
Digital I/O Lines
DT330 Series boards support 32 digital I/O lines through the digital input (DIN) and output
(DOUT) subsystems; the DIN and DOUT subsystems use the same digital I/O lines.
These lines are divided into four ports of eight: Port A, lines 0 to 7; Port B, lines 0 to 7; Port C,
lines 0 to 7; and Port D, lines 0 to 7. You can use each port for either input or output; all eight
lines within a port have the same configuration. For example, if you use Port A for input, lines
0 to 7 of Port A are configured as inputs. Likewise, if you use Port B for output, lines 0 to 7 of
Port B are configured as outputs.
Specify the digital I/O line to read or write in a single-value digital
I/O operation or a continuous digital input operation; refer to
page 59 for more information
on digital I/O operation modes.
On power up or reset, no digital data is output from the board.
Resolution
Using software, specify the number of digital I/O lines to read or write at once by specifying
the resolution as 8, 16, 24, or 32. Choosing a resolution greater than 8 effectively combines the
digital I/O ports.
Table 9 shows the effect of resolution on the number of digital I/O lines available for each
DIN or DOUT subsystem.
Table 9: Resolution, Digital I/O Lines, and Number of Subsystems
Resolution Digital I/O Lines DIN or DOUT Subsystem
8 Port A, lines 0 to 7 Element 0
Port B, lines 0 to 7 Element 1
Port C, lines 0 to 7 Element 2
Port D, lines 0 to 7 Element 3
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