Chapter 5
System Configuration
VME-MXI-2 User Manual
5-40
© National Instruments Corporation
Multiframe RM Operation
On power-up, all MXIbus devices are isolated from each other because
all address mapping windows are disabled. The multiframe RM
performs the following:
•
Identifies any VXIbus devices in the system
•
Manages system self-tests
•
Configures and enables the address map windows for logical
addresses, A16, A24, and A32
•
Establishes initial Commander/Servant system hierarchy, if any
•
Initiates normal system operation
Configuring the Logical Address Window
To identify all devices in the VMEbus/MXIbus system, the RM
performs the following steps, starting where the RM is located.
1.
If the multiframe RM resides in a PC, it scans all logical addresses
from 1 to FE (the RM is at address 0) to find all devices on the
MXIbus. For each logical address, it reads the VXIbus ID Register
(located at offset 0 within the device’s configuration space). If the
read is successful (that is, no BERR), a device is present at that
logical address. If the read returns a BERR, no device is present at
that logical address. The RM records all logical addresses found.
For each mainframe extender found, it performs Step 2.
If the multiframe RM is in a VMEbus mainframe, it performs
Step 2 for the mainframe in which the RM is installed.
2.
For the current mainframe, the RM does the following:
A. Scans all logical addresses (0 to FF) in the mainframe to find
all static configuration (SC) and dynamic configuration (DC)
devices, skipping over logical addresses occupied by
previously encountered devices. Finds the Slot 0 device and
uses it to move all DC devices in the mainframe to the lowest
unused logical addresses. Records all logical addresses found
and allocated.
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