Xycom XVME-240, Manual

Page: 16 / 73

XVME-240 Manual
October, 1984
2.4.2 Address Space Selection
The user is given the option of placing the DIO in VMEbus Short I/O or Standard
Memory Space. The selection is made by configuring jumper J2 and Switch 8 of Switch
Bank
2 (see Figure
2-3) as shown in Table 2-3 below.
Table 2-3. Addressing Options
Jumper Switch 8 Option Selected
J2A Open Standard Data Access Operation
J2B Closed Short I/O Access Operation
If jumper J2A is installed, Switch 8 must be set to
open.
If jumper J2B is installed, Switch 8 must be set to closed.
The Standard I/O Architecture recommends that the DIO operate within the Short I/O
Address Space, in order to take advantage of the Standard I/O Architecture% various
features, which are described in Appendix A.
If required, the DIO can operate in the Standard Address Space. The user should note
that in this mode, the DIO will always reside within the last 64K byte
segment
of the
Standard Memory Address Space
(i.e.,
the
address range FF0000H
through
FFFFFFH).
SUPERVISOR /
NON-PRIVILEGED
.
ADDRESS
SPACE
SELECTION
2 3 4 5 6
7 8
I
O P E N
Figure 2-3. Switch Bank S2
2-6