Specifications

Signal Simulation Characteristics 65
 Using the Stick High or Stick Low buttons in the Stick Signals
command.
Each of these methods is described in more detail in the relevant section of
this manual.
Clearing Stuck Levels
The stuck status can only be cleared by one of the following user actions:
 Typing the spacebar while viewing the signal using the signal probe
tool; or
 Clearing the “stuck” switch in the Stick Signals command.
Resolution of Multiple Device Outputs
The DONT0Z and DONT1Z values are used primarily to handle cases of
open collector or open emitter devices with unknown inputs (see following
additional information ). Most other types of devices produce the DONT01
output when a value cannot be calculated.
In cases where two or more device outputs are connected together and each
one drives the line with a different value, the following rules are used to
resolve the actual value on the line:
 The forcing/resistive distinction is only used to resolve outputs from
multiple devices. The final value used for display and simulation
purposes is one of the forcing values or HIGHZ.
 A forcing drive always overrides a resistive drive or HIGHZ (that is,
the signal takes on the value of the forcing drive, ignoring all resistive
drives and HIGHZs).
 A resistive drive always overrides HIGHZ.
 DONT0Z.F and LOW.F produce LOW.
 DONT1Z.F and HIGH.F produce HIGH.
 Any other combination of conflicting forcing drives produces CONF.
 DONT0Z.R and LOW.R produce LOW.
 DONT1Z.R and HIGH.R produce HIGH.
 Any other combination of conflicting resistive drives produces CONF.
LW Reference.bk Page 65 Monday, December 15, 2003 5:59 PM