( ESNUG 372 Item 17 ) ------------------------------------------- [05/31/01]
Subject: ( ESNUG 371 #6 ) TimeMill Troubles Reporting Transition Times
> I want to know if TimeMill can report nets with transition time greater
> than a specific threshold value. If so, which version of the TimeMill
> release can do this?
>
> - Raj Sayana
> MoSys, Inc. Sunnyvale, CA
From: [ A TimeMill CAE ]
John,
Nets with transition time greater than a specific threshold value can be
reported using the report_node_u command. Also, worst case rise/fall time
estimation can be done using the report_node_maxrf command. These commands
are available in version 5.2 and above.
Syntax:
report_node_u [status=1|2] [u_time=rf_time] [no=node_name1]
[no=node_name2] [except=node1]
OR
report_node_u [status=1|2] [rise=r_time] [fall=f_time]
[no=node_name1] [no=node_name2] [except=node1]
command
argument definition
-----------------------------------------------------
1|2 1: checks only nodes with fanout
(default if no nodes are specified)
2: reports all nodes
rf_time max time specified nodes can remain in
U-state before being reported (default = 5ns)
r_time max time a node's rising edge can remain
in U-state
f_time max time a node's falling edge can
remain in U-state
node_name* nodes to be diagnosed
node* nodes excluded from operation
Note that the U-state threshold voltages can be controlled with the
set_node_thresh command.
Example1:
report_node_u u_time=2.7ns no=adder.*
This example reports U-state warning for all matched nodes staying in
U-state longer than 2.7ns.
Example2:
report_node_u rise=3.5ns fall=2.7ns no=adder.*
This example reports U-state warning for all matched nodes staying in
U-state on the falling edge longer than 2.7ns or on the rising edge longer
than 3.5ns.
Syntax:
report_node_maxrf thresh_time node_name(s) [except=node1]
command
argument definition
-----------------------------------------------------
thresh_time rise/fall time threshold
node_name(s) nodes to be diagnosed
node* nodes excluded from operation
Example:
report_node_maxrf 5ns *
This example checks all nodes for worst-case rise or fall times exceeding
5ns. The worst-case rise/fall estimation uses total lumped capacitance of
the node and the effective resistance of the least conductive element
channel connected to the node.
- [ A TimeMill CAE ]
---- ---- ---- ---- ---- ---- ----
From: Raj Sayana <raj@mosys.com>
Hi John,
Please thank Synopsys for the information. I've found report_node_maxrf
gave very erroneous results. Perhaps they should either fix it or disable
the command. report_node_u is on the fly measurement & hence more accurate.
- Raj Sayana
MoSys
---- ---- ---- ---- ---- ---- ----
From [ Epic Support ]
Hi, Raj,
report_node_maxrf could be screwed up because it actually does the
estimation job according to node lump C value. And report_node_u is
checking during simulation while monitoring real transition time.
Thanks for your feedback!
- [ Epic Support ]
|
|
