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Digital I/O Features
DAS-8 Series boards contain three digital input lines and four digital
output lines. The digital input lines are associated with the IP1, IP2, and
IP3 pins on the main I/O connector; the digital output lines are associated
with the OP1, OP2, OP3, and OP4 pins on the main I/O connector. Logic
1 at a pin indicates that the input/output is high (greater than 2.0V); logic
0 at a pin indicates that the input/output is low (less than 0.8V).
The digital input lines are compatible with TTL-level signals. If no signal
is connected to a digital input line, the input appears high (logic 1).
You can use the digital input and output lines for any general-purpose
task, with the following exceptions:
•
If you are using an expansion board for an analog input operation, the
four digital output lines control the multiplexers on the expansion
boards to determine the expansion board channel that is acquiring
data. In this case, you cannot use the digital output lines for
general-purpose digital output operations.
•
If you are using an external digital trigger or hardware gate, you must
use the IP1 pin to attach the trigger/gate signal. In this case, you
cannot use IP1 for general-purpose digital input operations.
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