Impulse PIO-48.PC104 (3701) - Manual (Page 13)

© Sealevel Systems, Inc. - 11 - PIO-48.PC104 User Manual
Programming the PIO-48.PC104
Sealevel’s SeaI/O software is provided to assist in the development of reliable
applications for the Sealevel Systems family of digital I/O adapters. Included on the
SeaI/O CD are driver functions for use in accessing the I/O as well as helpful
samples and utilities.
Programming for Windows
The SeaI/O API (Application Programmer Interface) provides a variety of useful
high-level function calls implemented in a Windows dynamic link library (DLL).
The API is defined in the help file (Start/Programs/SeaIO/SeaIO Help) under
“Application Programmers Interface”. This help file also includes detailed
information dealing with installation / removal of the software and information
about latency, logic states, and device configuration.
For C language programmers we recommend using the API to access the
PIO-48.PC104. If you are programming in Visual Basic, using the ActiveX control
included with SeaI/O is advised.
Samples and Utilities
A variety of sample programs and utilities (both executable and source code) are
included with SeaI/O. Further documentation on these samples can be found by
selecting “Start/Programs/SeaIO/Sample Application Description”. Information
about where the files are physically stored on your disk is also included in this same
file.
Direct Hardware Control
In systems where the users program has direct access to the hardware (DOS) the
tables that follow give the mapping and functions that the PIO-48.PC104 provides.
Reading the Inputs
The inputs are active high. If an input is driven high (2V to 5.25 V) it will read as a
logical one, if driven low (0V to 0.8V) it will read as a logical zero. If an input is not
driven it will read as a one due to the 10K ohm pull up resistors on each port.
Reading the Outputs
The value that is currently being used to drive the outputs will be returned.