Configuration Extensions
126 372 SPU 780 01EMAN May 2002
Quantum VME Bus Extension
Overview The VME Bus extension lets a VME-424/X controller control data transfers between
devices on a master/slave Quantum network. In a master/slave p rotocol, one dev ice
(the "master") has control over other devices ("slaves"). As the network runs, each
element can lose and gain master status, based on negotiations with other members
of the network.
Editing the VME
Bus Extension In the Active Extensions panel select the VME Bus extension, then:
Note: If the VME Bus extension does not appear in the Active Extensions panel, it
is not a valid extension for the current controller type.
Step Action
1 Enter the appropriate value in the Slave Interrupt Level field. Boards on a VME
Bus can send and respond to messages on seven interrupt levels, numbered
from 1 to 7. This field determines which interrupt level the board uses when it’s
acting as a slave.
2 Enter a value between 1 and 255 in the Status ID field. When t he VME controller
receives an interrupt while acting as a slave, this is the value it sends.
3 Select an appropriate value for master arbitration type from the Master
Arbitration Type drop-down list. This field determines how the controller will
operate. Valid settings are Not System Controller, Primary Mode (PRI) or Round
Robin Mode (RRS).
4 Select an appropriate value for master release mode from the Master Release
Mode drop-down list. This field determines when a board acting as a master
relinquishes its master status. Valid settings are Release on Request (ROR),
Release When Done (RWD), Release On Clear (ROC), or Bus Capture and Hold
(BCAP). The proper setting depends on how your Quantum network is
configured.
5 Select the appropriate value for master VME Bus request level from the Master
Bus Request Level drop-down list. This field determines what priority the board
has when trying to acquire master status. It can range from BR0 (the lowest) to
BR3 (the highest).
6 For each interrupt level from Interrupt 1 to Interrupt 7, select whether it should
be Enabled or Disabled. These fields will only have an effect when the VME acts
as a master. If an interrupt level is:
Enabled - The controller responds to any messages sent on that interrupt.
Disabled - The controller ignores them.