XVME-2 12 Manual
August, 1989
2.4.2
Address Space Selection (J3)
The XVME-212
may be placed in VMEbus Short I/O or Standard Memory Space. The
selection is made by configuring Jumper J3 and Switch 8 of Switch Bank Sl (see Figure
2-2) as shown in Table 2-3 below.
Table 2-3. Addressing Options (J3)
Jumper
J3A
J3B
Switch 8 (Sl)
Open
Closed
Option Selected
.
Standard Data Access Operation
Short I/O Access Operation
If Jumper J3A is installed, Switch 8 (on Switch bank Sl) must be set to OPEN.
If Jumper J3B is installed, Switch 8 must be set to CLOSED.
The Standard I/O Architecture recommends that the XVME-212 operate within the Short
I/O Address Space, in order to take advantage of the Standard I/O Architecture’s various
features, which are described in Appendix
A.
If required, the XVME-212
can operate in the Standard Address Space. Note that in this
mode, the XVME-212 will always reside within the upper 64 Kbyte segment of the
Standard Memory Address Space (i.e., the address range FF0000H through FFFFFFH). Sl
switches 1 through 6, then determines which 1K block of the upper 64 Kbyte segment is
to be occupied.
2.4.3
Supervisory/Non-Privileged Mode Selection
The XVME-212 can be configured to respond only to supervisory access, or to both non-
privileged and supervisory accesses, by selecting the position of Switch 7 (located in
Switch Bank Sl, see Figure 2-2), as shown in Table 2-4 below.
Switch 7
Table 2-4. Privilege Options
Privilege Mode Selected
Closed
Open
Supervisory or Non-privileged
Supervisory Only
2.4.4
Address Modifier Reference
Table 2-5 below indicates the actual VMEbus Address Modifier code that the XVME-212
will respond to, based on the position of the options discussed in the previous two
sections.
2-7
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