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How to find the final time value of a signal?

swdesigner over 13 years ago

( I did search the forum and support.cadence.. no luck)

Say my simulation terminates earlier than the input file specifies, I want to analyze the last 10 us of a waveform.

How can I get tmax, which is the final timepoint?

xmax gives the time value corresponding to the max value that the signal attained.

Thanks

Parents

Andrew Beckett over 13 years ago

You could do this with ymax(xval(waveform)) but a more efficient way (for large waveforms) would be to use the code below:

/* abFirstLast.il

Author     A.D.Beckett
Group      Custom IC (UK), Cadence Design Systems Ltd.
Language   SKILL
Date       Mar 02, 2009 
Modified   
By         

Functions for finding the first and last X and Y points
in a waveform. To register abFirstX, abFirstY, abLastX, abLastY
with the calculator (so they show up in the user defined special
functions), call

abRegFirstLastCalcFunctions()

***************************************************

SCCS Info: @(#) abFirstLast.il 02/19/14.08:11:54 1.2

*/

/***************************************************************
*                                                              *
*                       (abFirstY wave)                        *
*                                                              *
*          Return the first Y value from the waveform          *
*                                                              *
***************************************************************/
(defun abFirstY (wave)
  (cond
    ((drIsWaveform wave)
     (drGetElem (drGetWaveformYVec wave) 0)
     )
    ((famIsFamily wave)
     (famMap 'abFirstY wave))
    (t
      (error "abFirstY: can't handle %L\n" wave)
      )
    )
  ) ; defun abFirstY

/***************************************************************
*                                                              *
*                       (abFirstX wave)                        *
*                                                              *
*          Return the first X value from the waveform          *
*                                                              *
***************************************************************/
(defun abFirstX (wave)
  (cond
    ((drIsWaveform wave)
     (drGetElem (drGetWaveformXVec wave) 0)
     )
    ((famIsFamily wave)
     (famMap 'abFirstX wave))
    (t
      (error "abFirstX: can't handle %L\n" wave)
      )
    )
  ) ; defun abFirstX

/***************************************************************
*                                                              *
*                        (abLastY wave)                        *
*                                                              *
*          Return the last Y value from the waveform           *
*                                                              *
***************************************************************/
(defun abLastY (wave)
  (cond
    ((drIsWaveform wave)
     (let (len vec)
       (setq vec (drGetWaveformYVec wave))
       (setq len (drVectorLength vec))
       (drGetElem vec (sub1 len))
       )
     )
    ((famIsFamily wave)
     (famMap 'abLastY wave))
    (t
      (error "abLastY: can't handle %L\n" wave)
      )
    )
  ) ; defun abLastY

/***************************************************************
*                                                              *
*                        (abLastX wave)                        *
*                                                              *
*          Return the last X value from the waveform           *
*                                                              *
***************************************************************/
(defun abLastX (wave)
  (cond
    ((drIsWaveform wave)
     (let (len vec)
       (setq vec (drGetWaveformXVec wave))
       (setq len (drVectorLength vec))
       (drGetElem vec (sub1 len))
       )
     )
    ((famIsFamily wave)
     (famMap 'abLastY wave))
    (t
      (error "abLastX: can't handle %L\n" wave)
      )
    )
  ) ; defun abLastX

/***************************************************************
*                                                              *
*                 (abFirstLastGenCB funcName)                  *
*                                                              *
*   Macro (and invocations) to build the calculator callback   *
*                          functions.                          *
*                                                              *
***************************************************************/
(defmacro abFirstLastGenCB (funcName)
  `(defun ,(concat funcName 'CB) ()
     (calSpecialFunctionInput (quote ,funcName) nil)
     ))
(abFirstLastGenCB abFirstX)
(abFirstLastGenCB abFirstY)
(abFirstLastGenCB abLastX)
(abFirstLastGenCB abLastY)

/***************************************************************
*                                                              *
*                (abRegFirstLastCalcFunctions)                 *
*                                                              *
* Register all four first/last functions as special functions  *
*                     for the calculator.                      *
*                                                              *
***************************************************************/
(defun abRegFirstLastCalcFunctions ()
  (foreach func '(abFirstX abFirstY abLastX abLastY)
           (calRegisterSpecialFunction
             (list (get_string func) (concat func 'CB)))
           )
  ) ; defun abRegFirstLastCalcFunctions

Reply

Andrew Beckett over 13 years ago

You could do this with ymax(xval(waveform)) but a more efficient way (for large waveforms) would be to use the code below:

/* abFirstLast.il

Author     A.D.Beckett
Group      Custom IC (UK), Cadence Design Systems Ltd.
Language   SKILL
Date       Mar 02, 2009 
Modified   
By         

Functions for finding the first and last X and Y points
in a waveform. To register abFirstX, abFirstY, abLastX, abLastY
with the calculator (so they show up in the user defined special
functions), call

abRegFirstLastCalcFunctions()

***************************************************

SCCS Info: @(#) abFirstLast.il 02/19/14.08:11:54 1.2

*/

/***************************************************************
*                                                              *
*                       (abFirstY wave)                        *
*                                                              *
*          Return the first Y value from the waveform          *
*                                                              *
***************************************************************/
(defun abFirstY (wave)
  (cond
    ((drIsWaveform wave)
     (drGetElem (drGetWaveformYVec wave) 0)
     )
    ((famIsFamily wave)
     (famMap 'abFirstY wave))
    (t
      (error "abFirstY: can't handle %L\n" wave)
      )
    )
  ) ; defun abFirstY

/***************************************************************
*                                                              *
*                       (abFirstX wave)                        *
*                                                              *
*          Return the first X value from the waveform          *
*                                                              *
***************************************************************/
(defun abFirstX (wave)
  (cond
    ((drIsWaveform wave)
     (drGetElem (drGetWaveformXVec wave) 0)
     )
    ((famIsFamily wave)
     (famMap 'abFirstX wave))
    (t
      (error "abFirstX: can't handle %L\n" wave)
      )
    )
  ) ; defun abFirstX

/***************************************************************
*                                                              *
*                        (abLastY wave)                        *
*                                                              *
*          Return the last Y value from the waveform           *
*                                                              *
***************************************************************/
(defun abLastY (wave)
  (cond
    ((drIsWaveform wave)
     (let (len vec)
       (setq vec (drGetWaveformYVec wave))
       (setq len (drVectorLength vec))
       (drGetElem vec (sub1 len))
       )
     )
    ((famIsFamily wave)
     (famMap 'abLastY wave))
    (t
      (error "abLastY: can't handle %L\n" wave)
      )
    )
  ) ; defun abLastY

/***************************************************************
*                                                              *
*                        (abLastX wave)                        *
*                                                              *
*          Return the last X value from the waveform           *
*                                                              *
***************************************************************/
(defun abLastX (wave)
  (cond
    ((drIsWaveform wave)
     (let (len vec)
       (setq vec (drGetWaveformXVec wave))
       (setq len (drVectorLength vec))
       (drGetElem vec (sub1 len))
       )
     )
    ((famIsFamily wave)
     (famMap 'abLastY wave))
    (t
      (error "abLastX: can't handle %L\n" wave)
      )
    )
  ) ; defun abLastX

/***************************************************************
*                                                              *
*                 (abFirstLastGenCB funcName)                  *
*                                                              *
*   Macro (and invocations) to build the calculator callback   *
*                          functions.                          *
*                                                              *
***************************************************************/
(defmacro abFirstLastGenCB (funcName)
  `(defun ,(concat funcName 'CB) ()
     (calSpecialFunctionInput (quote ,funcName) nil)
     ))
(abFirstLastGenCB abFirstX)
(abFirstLastGenCB abFirstY)
(abFirstLastGenCB abLastX)
(abFirstLastGenCB abLastY)

/***************************************************************
*                                                              *
*                (abRegFirstLastCalcFunctions)                 *
*                                                              *
* Register all four first/last functions as special functions  *
*                     for the calculator.                      *
*                                                              *
***************************************************************/
(defun abRegFirstLastCalcFunctions ()
  (foreach func '(abFirstX abFirstY abLastX abLastY)
           (calRegisterSpecialFunction
             (list (get_string func) (concat func 'CB)))
           )
  ) ; defun abRegFirstLastCalcFunctions

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