User manual

Glossary

synchronous communications A communications system that follows the command/response

cycle model. In this model, a device issues a command to

another device; the second device executes the command and

then returns a response. Synchronous commands are executed in

the order they are received.

Synchronous MXI Block Protocol A block data transfer protocol defined by the MXI-2

specification for high-performance data transfers.

Synchronous Protocol The most basic trigger protocol, simply a pulse of a minimum

duration on any one of the trigger lines.

SYSFAIL A VMEbus signal that is used by a device to indicate an internal

failure. A failed device asserts this line. In VXI, a device that

fails also clears its PASSed bit in its Status register.

SYSRESET A VMEbus signal that is used by a device to indicate a system

reset or power-up condition.

System Controller See MXIbus System Controller, VXIbus System Controller.

system hierarchy The tree structure of the Commander/Servant relationships of all

devices in the system at a given time. In the VXIbus structure,

each Servant has a Commander. A Commander can in turn be a

Servant to another Commander.

system RAM RAM installed on your personal computer and used by the

operating system, as contrasted with onboard RAM, which is

installed on the VXI-MXI-2.

terminators Also called terminating networks; devices located at the ends of

a MXIbus daisy-chain that are used to minimize reflections and

bias signals to their unasserted states.

TERMPWR Termination Power; 3.4 VDC for the MXIbus.

trigger Either TTL or ECL lines used for intermodule communication.

TTL Transistor-Transistor Logic