Motorola MVME2300 Series - Manual (Page 238)

4-14 Computer Group Literature Center Web Site
Universe (VMEbus to PCI) Chip
4
!
Caution
Register space marked as “Reserved” should not be overwritten.
Unimplemented registers return a value of 0 on reads; writes complete
normally.
Note The VMEbus CSR Bit Clear Register and the VMEbus CSR Bit
Set Register are not supported on the MVME2300. Writing a 1 to
the VMEbus CSR Bit Set Register reset bit will cause the board
to go into a permanent reset condition.
Universe Chip Problems after PCI Reset
Customers who overwrite the firmware settings for the Universe chip, or
who replace the MCG firmware with their own, may find that under the
conditions described below, there are problems with the Universe chip
after a PCI reset.
Description
The Universe chip is being enabled on the PCI bus after a PCI reset (the
problem does not occur after a board reset or power up).
The Universe is causing the "bye" command to hang the system. The
Universe Master Enable and Memory Enable in the PCI_CSR
(Configuration Space register) are enabled, even before the PCI_BS
register has been initialized. The symptoms can be alleviated by modifying
the PCI probe list such that the Universe PCI configuration is done first.
FF0 VME CR/CSR Reserved
FF4 VMEbus CSR Bit Clear Register VCSR_CLR
FF8 VMEbus CSR Bit Set Register VCSR_SET
FFC VMEbus CSR Base Address Register VCSR_BS
Table 4-2. Universe Register Map (Continued)
Offset Register Name