Measurement Computing Data Translation DT3034 User Manual page 95

Chapter 6
Digital I/O Features
This section describes the following features of the digital I/O subsystem:
• Digital I/O lines
• Digital I/O resolution
• Digital I/O operation modes
Digital I/O Lines
DT3034 boards support 16 digital I/O lines through the digital input (DIN) and output
(DOUT) subsystems; both subsystems use the same digital I/O lines. These lines are divided
into two banks of eight: Bank A, lines 0 to 7; and Bank B, lines 0 to 7. You can use each bank as
either an input port or an output port; all eight lines within a bank have the same
configuration. For example, if you use Bank A as an input port (port 0), lines 0 to 7 of Bank A
are configured as inputs. Likewise, if you use Bank B as an output port (port 1), lines 0 to 7 of
Bank B are configured as outputs.
Specify the digital I/O line to read or write in a single-value digital
I/O operation; refer to
A digital line is high if its value is 1; a digital line is low if its value is 0.
On power up or reset, no digital data is output from the board.
Digital I/O Resolution
Using software, specify the number of banks to read by specifying the resolution as 8 (for
eight lines) or 16 (for 16 lines). If you specify a resolution of 8, two digital I/O subsystems are
available. Element 0 (the first subsystem) corresponds to the Bank A, lines 0 to 7. Element 1
(the second subsystem) corresponds to Bank B, lines 0 to 7. If you specify a resolution of 16,
one subsystem is available.
Note: When the resolution is 16, digital I/O lines 0 to 7 of Bank B are represented as bits 8 to
15 of the digital value.
Digital I/O Operation Modes
DT3034 boards support the following digital I/O operation modes:
• Single-value operations are the simplest to use but offer the least flexibility and
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efficiency. Use software to specify the digital I/O line, and a gain of 1 (the gain is ignored).
Data is then read from or written to the digital I/O line. For a single-value operation, you
cannot specify a clock or trigger source.
Single-value operations stop automatically when finished; you cannot stop a single-value
operation.
for more information on single-value operations.