Xycom XVME-678 Manual page 53

3.3.2.3 Master Access Mode (Non-Privileged/Supervisory)
XVME-6781688 Manual
July 1994
This field allows the choice of Non-privileged or Supervisory accesses for VME master cycles. The access
mode selection controls the AM2 signal on the VMEbus when the XVME-678/688 performs VMEbus
accesses.
3.3.2.4 System Resources (Display Only)
This option displays the state of the SYSRES switch, which determines if the VMEbus system resources
are provided by the XVME-678/688 or another VMEbus processor. The system resources are VMEbus
Arbiter, BERR timeout, SYSCLK, and lACK daisy chain driver. These resources must be provided by
the module installed in VMEbus slot 1.
3.3.2.5 VMEbus Request Level (01112/3)
This feature sets which bus request level (0,1,2,3) will be used by the XVME-678/688 when requesting
use of the VMEbus. If the XVME-678/688 is providing the system resources, this selection is
automatically set to 3.
3.3.2.6 VMEbus BERR Timeout
If system resources are enabled, the length of the VMEbus BERR timeout is 16
/J-S.
If system resources
are disabled, this option is unavailable.
3.3.2.7 Auxiliary NMI Configuration
The XVME-678/688 has both individual and group enable bits for the auxiliary non-maskable interrupts
(ANMls) and auxiliary maskable interrupts (AMls). Individual ANMI and AMI bits are configured by
the VMEbus master menu, but the group enable bits are left disabled and must be enabled by software
(via XVME BIOS functions 21H and 51H, or by directly setting bit 4 and/or bit 7 of CONREGI-I10
port 30H) before the actual interrupts can be processed. This is because non-maskable interrupts (NMls)
and IRQlO handlers must be provided by a user application or the operating system, not by the BIOS.
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