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Programming Considerations Chapter 5
VXI-MXI User Manual 5-38 © National Instruments Corporation
9. Enables the logical address window of the VXI-MXI in VXIbus Mainframe #2 for the entire
inward mapping range of 0 to FF. Scans all logical addresses, skipping all previously
encountered devices and defined ranges. Finds the Slot 0 device and uses it to move all DC
devices in VXIbus Mainframe #2 to the lowest unused logical addresses. No more
VXI-MXI interfaces are found. The RM enables the logical address window for the
VXI-MXI in VXIbus Mainframe #2 with an inward range of C0 to DF hex by writing the
value 63C0 hex to the Logical Address Window Register (Base/Size format).
10. Sets the logical address window of the VXI-MXI found in VXIbus Mainframe #1 at logical
address 2 to cover the devices connected to that extender: the VXI-MXI in VXIbus
Mainframe #3 (80 to BF), the VXI-MXI in VXIbus Mainframe #2 (C0 to DF), MXIbus
Device A (E0 to E3), and MXIbus Device B (E4). Enables the logical address window of
the VXI-MXI at logical address 2 with an outward range of 80 to FF by writing the value
4180 hex to the Logical Address Window Register (Base/Size format).
11. Enables the logical address window of the VXI-MXI found at logical address 4 for the
entire outward mapping range of 0 to FF. Scans all logical addresses, skipping all
previously encountered devices, and finds the VXI-MXI in VXIbus Mainframe #6.
12. Enables the logical address window of the VXI-MXI in VXIbus Mainframe #6 for the
entire inward mapping range of 0 to FF. Scans all logical addresses, skipping all previously
encountered devices and defined ranges, and finds the VXI-MXI at logical address 10.
Finds the Slot 0 device and uses it to move all DC devices in VXIbus Mainframe #6 to the
lowest unused logical addresses. No more VXI-MXI interfaces are found. The RM enables
the logical address window for the VXI-MXI in VXIbus Mainframe #6 with an inward range
of 10 to 17 hex by writing the value 6510 hex to the Logical Address Window Register
(Base/Size format).
13. Sets the logical address window of the VXI-MXI found in VXIbus Mainframe #1 at logical
address 4 to cover the devices connected to that extender: the VXI-MXI in VXIbus
Mainframe #6 (10 to 17). Enables the logical address window of the VXI-MXI at logical
address 4 with an outward range of 10 to 17 by writing the value 4510 hex to the Logical
Address Window Register (Base/Size format).
Configuring the A24 and A32 Addressing Windows
After the logical address space is configured for the system, the multiframe RM configures the
A16, A24 and A32 address space. The logical address configuration forms a tree topology.
Starting at the bottom of the tree and working up, add up the amount of memory needed by each
mainframe and the devices on levels below it. That amount is then rounded up to the next power
of 2 if the Base/Size format is used.
Starting at the root mainframe and working down each branch of the tree, assign memory starting
with the largest memory window requirements at the top of the memory space, descending in
order of window size and address location.
Each mainframe's A16, A24, and A32 address ranges define the address space occupied by the
devices in that mainframe and on levels below that mainframe. These address ranges cannot
overlap the defined range of any other mainframe unless that mainframe is on a level below the
mainframe.