Glossary
6711/6713/6715 User Manual
G-4
www.ni.com
DMA
direct memory access—a method by which data can be transferred to/from
computer memory from/to a device or memory on the bus while the
processor does something else. DMA is the fastest method of transferring
data to/from computer memory.
DNL
differential nonlinearity—a measure in least significant bit of the
worst-case deviation of code widths from their ideal value of 1 LSB
DO
digital output
E
EEPROM
electrically erasable programmable read-only memory—ROM that can be
erased with an electrical signal and reprogrammed
EXTSTROBE
external strobe signal
F
FIFO
first-in first-out memory buffer—FIFOs are often used on DAQ devices to
temporarily store incoming or outgoing data until that data can be read or
written. For example, an analog input FIFO stores the results of A/D
conversions until the data can be read into system memory. Programming
the DMA controller and servicing interrupts can take several milliseconds
in some cases. During this time, data accumulates in the FIFO for future
retrieval. With a larger FIFO, longer latencies can be tolerated. In the case
of analog output, a FIFO permits faster update rates, because the waveform
data can be stored in the FIFO ahead of time. This again reduces the effect
of latencies associated with getting the data from system memory to the
DAQ device.
FREQ_OUT
frequency output signal
ft
feet
G
GATE
gate signal
GPCTR
general-purpose counter signal
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com
