User`s manual

ENV - Set Environment
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To enable prefetch reads for incoming VMEbus block read
cycles, OR the following value with those chosen above:
0x20000000
To enable posted writes of incoming data on the VMEbus, OR
the following value with those chosen above: 0x40000000
To enable the selected VME Slave Image Map Decoder, OR
the following value with those chosen above: 0x80000000
As an example, a control value of: 0xE0F20000
decodes A32, non-privileged and supervisor, data and
program VMEbus space, with prefetch reads, and posted
writes enabled.
It is the userÕs responsibility to ensure that the selected
control bits are not destructive, and that the resources present
on the VMEbus and PCI bus support the access and
transaction controls chosen.
ENV Command Parameters
The parameters that can be configured with ENV are listed and
described in your board-specific installation and use manual.
Systems with Wide SCSI Drives Running AIX
If AIX (or some other OS) is booted on a system with wide SCSI
drives, and then the system is reset, PPCBug will not be able to
access the wide SCSI drives. This problem may be corrected by
running ENV and enabling PPCBug to reset the SCSI bus on startup
as follows:
Local SCSI Bus Reset on Debugger Startup [Y/N] = N? y
This ENV change should be made to all PowerPlus architecture
systems running AIX.
Note This problem is fixed in PPCBug release 3.2 and later.