EPC-7 Hardware Reference
BUS RELEASE METHOD
This field entry toggles between two bus release modes: ROR (release on request)
and RONR (request on no request, also known as the VXI fair-requester mode).
ROR results in slightly better EPC-7 performance when accessing the VXIbus;
RONR directs the EPC-7 to not "park" on the bus and thus slightly improves the
access time of other VXIbus masters to the bus. When using RONR, all masters on
the VXIbus should be set to RONR to avoid a starvation condition where one master
never gains access to the bus.
BUS ARBITRATION
4
4
This field toggles between the two arbitration algorithms provided by the EPC-7:
priority arbitration and round-robin arbitration. This field is only used when the
EPC-7 is configured as the slot-0 controller:
COM1, COM2, LPT1
These fields toggle between the enabled and disabled states. The enabled state
enables the controllers for these I/O ports. The disabled state means that the
associated I/O port is disabled, and the I/O addresses and IRQs associated with the
controller for the port are not responded to by the controller. Putting a port in the
disabled state allows use of I/O modules that may have conflicting addresses or IRQs
with the built-in ports.
EXM Configuration
A separate EXM setup screen is used to configure the EXM modules in the system. It
is displayed by pressing the F2 function key from the main setup screen. The
EPC-7's nonvolatile (battery-backed) CMOS holds identification and configuration
information for up to six EXM module slots. Note that six EXM slots are indicated
even in systems that do not have six EXM slots available. An EPC-7MC module
carrier can be added to a standard EPC-7 to provide two additional EXM slots. This
is a factory-installed option only.
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