ICS DIO48S/AT-P Series, Product Manual

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Page 6-1
Manual 00650-526-1
Chapter 6: Programming
The DIO48S/AT-P is an I/O-mapped device that is easily configured from any language and any
language can easily perform digital I/O through the card's ports. This is especially true if the form
of the data is byte or word wide. All references to the I/O ports would be in absolute port
addressing. However, a table could be used to convert the byte or word data ports to a logical
reference.
Developing Your Application Software
If you wish to gain a better understanding of the programs, then the information in the following
paragraphs will be of interest to you. Refer to the data sheets and 8255-5 specification in
Appendix A.
A total of 16 address locations are used by the DIO48S/AT-P. The PPIs are addressed
consecutively with Address bits A3 through A0 as follows:
Address Port Assignment Operation
Base Address PA Group 0 Read/Write
Base A1 PB Group 0 Read/Write
Base A2 PC Group 0 Read Write
Base A3 Control Group 0 Write Only
Base A4 PA Group 1 Read/Write
Base A5 PB Group 1 Read/Write
Base A6 PC Group 1 Read/Write
Base A7 Control Group 1 Write Only
Base A8 Enable/Disable Buffer, Grp 0 Write Only
Base A9 Enable/Disable Buffer, Grp 1 Write Only
Base AB Enable Chg-of-St. Interrupt Write Only
Base AF Clear Chg-of-St. Interrupt Write Only
Table 6-1: Address Selection Table
The DIO48S/AT-P card uses two 8255-5 PPIs to provide a total of 48 bits input/output capability.
The card is designed to use each of these PPIs in Mode 0 wherein:
a. There are two 8-bit ports (A and B) and two 4-bit ports (C Hi and C Lo).
b. Any port can be configured as an input or an output.
c. Outputs are latched.
d. Inputs are not latched.