Contec DIO-48DX-USB, Руководство пользователя

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5. Function
DIO-48DX-USB
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5. Function
This section describes the features of this product.
Each function described here can be easily set and executed by using the bundled API driver library. For
details, refer to API-DIO HELP available after installation.
Data I/O Function
This product supports the equivalence to the mode 0 of two i8255 chips, capable of input/output of up to
48 TTL-level active high signals.
I/O setup of the port
The I/O function of the port must be set properly before the board can input/output data correctly.
Writing a control word sets each port for either input or output.
The input/output setting can be achieved in eight signals unit for ports A and B and in four signals unit
(upper 4 bits and lower 4 bits) for port C.
CAUTION
Each port is assigned as an input port when the power is turned on.
Start
set i8255 function
input/output data
end
Figure 5.1. I/O setup