Specifications

Device Pin Type and Simulator Efficiency 241
Device Pin Type and Simulator Efficiency
Incorrect device pin type settings can have a major impact on simulation
speed, even in cases where they do not affect the correctness of the results.
Bidirectional Pins
Using bidirectional pins should be avoided unless specifically required by
circuit logic. On primitive types, any value change on a signal attached to a
bidirectional pin will cause the device model to be called to reevaluate the
Pin Type Description Initial
Value
Output
Value
Mapping
LTCHIN Input to a transparent latch—this is used for
calculating cumulative setup and hold
times.
HIGHZ No output
drive
allowed.
LTCHOUT Output from a transparent latch—this is
used for calculating cumulative setup and
hold times.
DONT01 Same as
OUT.
CLKIN Input to an edge-triggered latch—this is
used for calculating cumulative setup and
hold times.
HIGHZ No output
drive
allowed.
CLKOUT Output from an edge-triggered latch—this
is used for calculating cumulative setup and
hold times.
DONT01 Same as
OUT.
Clock Clock input—this is used for calculating
cumulative setup and hold times.
HIGHZ No output
drive
allowed.
OE Open emitter output—i.e., can pull up but
not down.
DONT1Z LOW maps
to HIGHZ.
NC A no-connect pin. HIGHZ No output
drive
allowed.
LW Reference.bk Page 241 Monday, December 15, 2003 5:59 PM