Xycom XVME-240, Manual

Page: 28 / 73

XVME-240 Manual
October, 1984
Chapter 3
USING THE DIO MODULE
3.1 INTRODUCTION
This chapter provides the information needed to program the DIO to perform Input
and/or Output data transfers and how to use the unique design features which are a
part of XYCOM I/O modules. The chapter is arranged in the following order:
-
Module base addressing
- The Module I/O Interface Block and how it is addressed
-
Interrupts
3.2 MODULE BASE ADDRESSING
XYCOM I/O modules are designed to be addressed within the VMEbus-defined 64K
Short I/O Address space. When the DIO module is installed it will occupy a 1K byte
block of the Short I/O Address space (referred to as the module I/O Interface Block).
The starting address for each I/O Interface Block must reside on a 1K boundary. Thus,
the module base address will be one of the 64 - 1K boundaries available within the
Short I/O Address space (refer to Chapter 2, Table 2-2 for a complete list of the 64 -
1 K boundaries).
Figure 3-l shows the module I/O Interface Block for the DIO and how it relates to the
Short I/O Address space. In this example, the module base address resides on the
1K
boundary at 1000H (refer to Chapter 2, Section 2.4.1 for information on using base
address switches). This means that the module would occupy the
1K
block from lOOOH
t o 1400H.
3-l