User manual

Chapter 6 System Configuration
VXI-MXI-2 User Manual 6-26 © National Instruments Corporation
10. Each first-level MXIbus link is connected to the RM through a
VXI-MXI-2. The A16 window for MXIbus link #1 is 16 KB in
size. We assign the next lowest available 16 KB portion of A16
space to MXIbus link #1, which is address range 4000 to 7FFF
hex. (See Figure 6-20.) The base address of this window is 4000,
which we enter into Figure 6-21. The Size field for the window is i
where the size of the window = 256
*
2
8-i
. 16 KB = 256
*
2
8-2
, so
Size = 2. The direction of the window is in relation to the
mainframe; therefore, Direction = Out.
11. The other first-level MXIbus link is MXIbus #2, which needs 2 KB
of A16 space. The next lowest available 2 KB portion of A16
space is 8000 through 87FF hex. We set the base address of the
window to 8000. To determine the Size value, 2 KB = 256
*
2
8-5
,
so Size = 5. The direction of the window is in relation to the
mainframe; therefore, Direction = Out. We enter all of these values
into the worksheet in Figure 6-21.
12. The VXI-MXI-2 in VXIbus Mainframe #2 will be configured so
that all A16 space is mapped outward, because the mainframe does
not require any A16 space. To do this, we set Base = 0, Size = 0,
and Direction = Out.
13. The VXI-MXI-2 in VXIbus Mainframe #3 should be assigned the
lowest available 8 KB of space assigned to MXIbus #1. Therefore,
the base should be 4000 hex, and because 8 KB = 256
*
2
8-3
,
Size = 3. The direction of the window is in relation to the
mainframe; therefore, it is In. The VXI-MXI-2 connected to
MXIbus #3 must be assigned a window within the range of
addresses assigned to Mainframe #3. Devices in Mainframe #3
need 4 KB of the 8 KB assigned to the mainframe. The other 4 KB
can be assigned to MXIbus #3. Therefore, we assign addresses
4000 to 4FFF hex to devices in Mainframe #3, and addresses 5000
through 5FFF to MXIbus #3. For the VXI-MXI-2 connected to
MXIbus #3, we set Base = 5000, Size = 4 because
4 KB = 256
*
2
8-4
, and the direction toward MXIbus #3, or Out.
14. The 4 KB assigned to MXIbus #3 is further divided between
VXIbus Mainframes #4 and #5. We assigned the bottom portion,
5000 to 57FF, to VXIbus Mainframe #4, and the next portion,
5800 to 5BFF, to VXIbus Mainframe #5. Therefore, for VXIbus
Mainframe #4, we assign Base = 5000, Size = 5 because
2 KB = 256
*
2
8-5
, and Direction = In. For VXIbus Mainframe #5,
Base = 5800, Size = 6 because 1 KB = 256
*
2
8-6
, and
Direction = In.