Pci Reset Problems Associated With The Initial Version Of The Universe Chip; Problem Description - Motorola MVME2600 Series Reference Manual

Universe (VMEbus to PCI) Chip
PCI Reset Problems Associated with the Initial
Version of the Universe Chip
4

Problem Description

4-14
Under the conditions described below, there are problems with the
Universe chip after a PCI reset.
Note These problems were addressed by fixes in the second
version of the Universe chip, Universe II. The Tundra part
number for the Universe II chip is CA91C142. The following
problem description applies only to MVME2600 SBCs with
the original Universe chip, Tundra part number CA91C042.
(All MVME2700 boards include the Universe II chip.)
You can check to see if your board contains the original
Universe chip, and if the following information is relevant to
your SBC, by checking the Tundra part number printed on
the chip.
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.
The Configuration Space enables are not the only things enabled after a
PCI reset. The LSI0 image may also not be disabled by a PCI reset,
regardless of the enable bit's Power Up condition. If the image is active at
the time the reset occurs, it will remain enabled through the reset.
Additionally, the image is not staying at the same VME or PCI address
range.