Xycom XVME-240 User Manual page 16

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.
Jumper
J2A
J2B
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
2
I
Table 2-3. Addressing Options
Switch 8
Open Standard Data Access Operation
Closed Short I/O Access Operation
(i.e., address range FF0000H
the
3 4 5
O P E N
Figure 2-3. Switch Bank S2
Option Selected
.
6
7 8
2-6
FFFFFFH).
through
SUPERVISOR /
NON-PRIVILEGED
ADDRESS
SPACE
SELECTION