User manual

Glossary

daisy-chain A method of propagating signals along a bus, in which the

devices are prioritized on the basis of their position on the bus.

Data Transfer Bus DTB; one of four buses on the VMEbus backplane. The DTB is

used by a bus master to transfer binary data between itself and a

slave device.

deadlock Unresolved situation in which two devices are vying for the use

of a resource.

DIP Dual Inline Package

DMA Direct Memory Access; a method by which data is transferred

between devices and internal memory without intervention of

the central processing unit.

DRAM Dynamic RAM (Random Access Memory)

DTACK* Data Acknowledge signal

DTB See Data Transfer Bus.

dynamic configuration A method of automatically assigning logical addresses to

VXIbus devices at system startup or other configuration times.

dynamically configured device A device that has its logical address assigned by the Resource

Manager. A VXI device initially responds at Logical Address

255 when its MODID line is asserted. A MXIbus device

responds at Logical Address 255 during a priority select cycle.

The Resource Manager subsequently assigns it a new logical

address, which the device responds to until powered down.

ECL Emitter-Coupled Logic

EEPROM Electronically Erasable Programmable Read Only Memory

embedded controller An intelligent CPU (controller) interface plugged directly into

the VXI backplane, giving it direct access to the VXIbus. It must

have all of its required VXI interface capabilities built in.