Glossary
NI-VXI User Manual
G-12
© National Instruments Corporation
ROAK
Release On Acknowledge; a type of VXI interrupter which always
deasserts its interrupt line in response to an IACK cycle on the VXIbus.
All message-based VXI interrupters must be ROAK interrupters.
ROR
Release On Request; a type of VME bus arbitration where the current
VMEbus master relinquishes control of the bus only when another bus
master requests the VMEbus.
RORA
Release On Register Access; a type of VXI/VME interrupter which
does not deassert its interrupt line in response to an IACK cycle on the
VXIbus. A device-specific register access is required to remove the
interrupt condition from the VXIbus. The VXI specification
recommends that VXI interrupters be only ROAK interrupters.
RR
Read Ready; a bit in the Response register of a message-based device
used in Word Serial Protocol indicating that a response to a previously
sent query is pending.
RRviol
Read Ready protocol violation; a type of Word Serial Protocol error. If
a Commander attempts to read a response from the Data Low register
when the device is not Read Ready (does not have a response pending),
a Read Ready violation may be generated.
rsv
Request Service; a bit in the status byte of an IEEE 488.1 and 488.2
device indicating a need for service. In VXI, whenever a new need for
service arises, the rsv bit should be set and the REQT signal sent to the
Commander. The rsv bit should be automatically deasserted when the
Word Serial Read Status Byte query is sent.
S
s
Seconds
SEMI-SYNC Protocol
A one-line, open collector, multiple-device handshake trigger protocol.
Servant
A device controlled by a Commander.
setting
To place a binary cell into the 1 (non-zero) state.
Shared Memory Protocol A communications protocol for message-based devices that uses a
block of memory that is accessible to both a client and a server. The
memory block acts as the medium for the protocol transmission.
short integer
Data type of 16 bits, same as word.
