Dynamic Pulse Width Check (dyn_pulsewidth)

Spectre Syntax

title dyn_pulsewidth node=[n1 n2 ...] pwmin_low=<value> pwmax_low=<value> pwmin_high=<value>  pwmax_high=<value> vlth=<value> vhth=<value> time_window=[start1 stop1 start2 stop2 ....] <save=no|violation> <spice=no|yes> <inst=[inst1 inst2...]> <xinst=[xinst1 xinst2...]> <subckt=[subckt1 subckt2....]> <xsubckt=[xsubckt1 xsubckt2....]> <fanout=all|gate|bulk> <depth=n> error_limit=<value>

SPICE Syntax

.cck title dyn_pulsewidth node=[n1 n2 ...] pwmin_low=<value> pwmax_low=<value> pwmin_high=<value>  pwmax_high=<value> vlth=<value> vhth=<value> time_window=[start1 stop1 start2 stop2 ....] <save=no|violation> <spice=no|yes> <inst=[inst1 inst2...]> <xinst=[xinst1 xinst2...]> <subckt=[subckt1 subckt2....]> <xsubckt=[xsubckt1 xsubckt2....]> <fanout=all|gate|bulk> <depth=n> error_limit=<value>

Description

The pulse width of a logic low state signal is the duration between which the signal crosses the low voltage threshold (vlth) while falling and again crosses vlth while rising. If this duration is outside the range specified using the pwmin_low and pwmax_low parameters, the dyn_pulsewidth check reports the pulse width of such signals.

Similarly, the pulse width of a logic high state signal is the duration between which the signal crosses the high voltage threshold (vhth) while rising and again crosses vhth while falling. If this duration is outside the range of pwmin_high and pwmax_high parameters, the dyn_pulsewidth check reports the pulse width of such signals.

The results are written to a file with the extension dynamic.xml, which can be viewed with a Web browser.

Arguments

node	Nodes to which the check is applied. Default is none.
pwmin_low	Minimum value of the pulse width in logic low state. Default is 0.0 sec.
pwmax_low	Maximum value of the pulse width in logic low state. Default is infinity sec.
pwmin_high	Minimum value of the pulse width in logic high state. Default is 0.0 sec.
pwmax_high	Maximum value of the pulse width in logic high state. Default is infinity sec.
vlth	Low voltage threshold for the signal net. Default is 0.2v.
vhth	High voltage threshold for the signal net. Default is 0.8v.
time_window	Time window to which the circuit check is applied. Multiple non-overlapping time windows are supported. Default time window is 0 to tend.
save	Specifies how to probe the signals specified within this circuit check. Possible values are: no: None of the signals in this circuit check are probed. This is the default value. violation: Automatically probe the signals with violations under this circuit check.
spice	Specifies whether to save the probed signals specified by the save parameter in the SPICE syntax. Possible values are: yes: Saves the signals in SPICE syntax no: Saves the signals in Spectre syntax. This is the default value.
error_limit	Maximum number of errors to be reported. Default is 10000.
inst	Subcircuit instances to which the circuit check is applied. Default is inst=*
xinst	Subcircuit instances that are excluded from the circuit check. Default is none.
subckt	Instances of the specified subcircuit to which the circuit checks are applied. Default is subckt=*.
xsubckt	Instances of the specified subcircuit which are excluded from the circuit checks. Default is none.
fanout	Fanout setting to filter node with specified connection. Possible values are all, gate, and bulk. Default is all.
depth	Hierarchy level (from top level) to be checked. depth=3 reports errors on top level plus 3 sublevels. Default is 8.

Example

Spectre Syntax

chk1 dyn_pulsewidth node=[*] pwmin_low=20n pwmax_low=40n pwmin_high=20n pwmax_high=40n vlth=0.2 vhth=1.0

SPICE Syntax

.cck chk1 dyn_pulsewidth node=[*] pwmin_low=20n pwmax_low=40n pwmin_high=20n pwmax_high=40n vlth=0.2 vhth=1.0

The above command reports all nodes that specify either of the following conditions:

• The pulse width in logic low state is outside the range of parameters pwmin_low (20n) and pwmax_low (40n).
• The pulse width in logic high state is outside the range of parameters pwmin_high (20n) and pwmax_high (40n).

The following is an example of the report that is displayed in the Web browser.

Related Topics

Dynamic Checks

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