Unit installation

Glossary
Altera Corporation 313
Glossary
Glossary
Hierarchy Interconnect File (.hif) An ASCII
file (with the extension .hif) created by the
CompilerÕs Netlist Extractor module. This
file specifies the hierarchical
interconnections between design files in a
project.
History File (.hst) An ASCII file (with the
extension .hst) created by the
MAX+PLUS II Simulator. This time period
records all commands, buttons, and on-
screen options that are used during a
simulation session, as well as their output.
hold time On a flipflop, the hold time is
the minimum time period for which a
signal must be retained on an input pin that
feeds the data input or Clock Enable after
an active transition at the input pin that
feeds the flipflopÕs Clock input.
On a latch, the hold time is the minimum
time period for which a signal must be
retained on an input pin that feeds the D
input after an active transition at the input
pin that feeds the Latch Enable input.
On an asynchronous RAM block, the hold
time is the minimum time period for which
a signal must be retained on an input pin
that feeds the data or address inputs after
an active transition at the input pin that
feeds the RAM blockÕs Write Enable input.
Internal hold times for flipflops, latches,
and asynchronous RAM, which are not
user-controllable, similarly constrain
internally generated signals.
I
I/O cell An I/O cell is a register (also
known as an I/O element) that exists on the
periphery of a FLEX 10K, FLEX 8000, or
MAX 9000 device. I/O cells permit short
setup time.
1 In pre-version 5.0 releases of
MAX+PLUS II, I/O cells were
known as peripheral registers.
I/O feedback Feedback from the output
pin on an Altera device. It allows an output
pin to be also used as an input pin.
I/O type The direction of signal travel for a
node, pin, or state machine.
In the Graphic and Symbol Editors, pins
and pinstubs can have I/O types of input,
output, or bidirectional.
In AHDL, the I/O type of a port can be
input, output, buried (i.e., buried output),
machine input, or machine output.
In the Waveform Editor, the I/O type of a
node can be input, output, or buried (i.e.,
buried output). Input and output I/O
types can represent actual pin outputs; a
buried I/O type always represents logic
that does not feed a pin.
ICR see in-circuit reconfigurability.
in-circuit reconfigurability (ICR) The
capability of SRAM-based devices, such as
AlteraÕs FLEX 6000, FLEX 8000, and
FLEX 10K devices, to load configuration
data at system power-up or during normal
system operation after they have been
mounted on a printed circuit board.
In-circuit reconfiguration can be
performed an unlimited number of times
with data from a local PROM such as an
Altera Configuration EPROM, or with data
downloaded by an external controller such
as a CPU or the MAX+PLUS II
81_GSBOOK.fm5 Page 313 Tuesday, October 14, 1997 4:04 PM