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Cenlasoft · 2012-05-14 09:40

Hello,
I modified Beau's inductive proximity1 code and used the new object for the Prop BOE. My program works great where I find the resonant frequency using the calibrate procedure. In the code below, i put in some debug code using the Propeller Serial Terminal plus object to see what ad values and frequencies were reported. When the values for ad reach 1023, I get several values and the frequency that is chosen is the last of the list. How do I get it to pick the first one that is 1023?
Thanks,
Cenlasoft

OBJ

  system : "Propeller Board of Education"              ' PropBOE configuration tools
  pst    : "Parallax Serial Terminal Plus"             ' Terminal communication tools
  adc    : "PropBOE ADC"                               ' A/D Converter on PropBOE
  time   : "Timing"                                    ' Timing convenience methods


CON

  FPin     = 7                  'Frequency Synthesizer OUTPUT pin
  New_Freq      = 261_000
  StartFrequency = 100_000       'Start Frequency to Sweep ... 0 kHz to 500 kHz
  StopFrequency = 400_000       'Stop Frequency to Sweep ... .0 kHz to 500 kHz
  SweepStep = 1_000             'Sweep increment used in auto calibration
VAR

  long ad                                              ' Stores A/D conversion Result
  long Frequency,FMax,ADCMax

PUB Go                                                 ' Program starts here

  system.Clock(80_000_000)                             ' Propeller system clock -> 80 MHz
  Calibrate

  repeat
    Synth(FPin,FMax)
    ad := adc.In(0)                                     ' Get AD0 analog to digitla conversion
    time.Pause(50)                                      'Delay 50ms
    pst.Home                                    
    pst.Str(String("ADC Val = "))
    pst.Dec(ad)
    pst.Str(String(" , "))
    pst.Dec(FMax)
    pst.ClearEnd
    
 
PUB Calibrate
FMax~              
ADCMax := 1023

repeat Frequency from StartFrequency to StopFrequency step SweepStep            'Sweep frequency range
  Synth(FPin,Frequency)
  ad := adc.In(0)
  waitcnt(cnt+clkfreq>>10)                                                      'Allow ADC to settle
  if ad => ADCMax
    ADCMax := ad
    FMax := Frequency
    pst.dec(ad)
    pst.Str(String(", "))
    pst.Dec(Frequency)
    pst.NewLine

PUB Synth(Pin, Freq) | s, d, ctr, frq
{{
##########################################################################################
##########################################################################################
 Section used to Synthesize a specific frequency on an I/O pin:
##########################################################################################
##########################################################################################
}}    
    Freq := Freq #> 0 <# 500_000                        'limit frequency range
  
    ctr := constant(%000100 << 26)                       '..set NCO mode
    s := 1                                               'determine shift
    frq := fraction(Freq, CLKFREQ, s)                    'Compute FRQB value
    ctr |= Pin                                           'set PINA to complete CTRB value
    CTRB := ctr                                          'Set CTRB
    FRQB := frq                                          'Set FRQB
    DIRA[Pin]~~                                          'make pin output
    
PRI fraction(a, b, shift) : f
    if shift > 0                                        'if shift, pre-shift a or b left
      a <<= shift                                       'to maintain significant bits while 
    if shift < 0                                        'insuring proper result
      b <<= -shift
    repeat 32                                           'perform long division of a/b
      f <<= 1
      if a => b
        a -= b
        f++           
      a <<= 1

Duane Degn · 2012-05-15 11:30

Cenlasoft,

You might get more replies if you attach an archive of your project with your post.

I personally don't have all the objects listed in your program and I didn't want to go hunt them down.

I'm not sure I understand your question.

Do you want the loop to stop as soon as the variable "ad" equals 1023?

You mentioned Beau's code. Is there more information about his code? Do you have a link?

Cenlasoft · 2012-05-15 14:06

Thanks Duane,
Your right, but all I want is to stop the loop as soon as "ad" equals 1023. This will give me the first resonant frequency value. I have tried to change the "=>" to "==" and then use "Next" in the loop. I need to know where to put the "Next" statement to exit the loop as soon as it hits 1023.
Thanks
Cenlasoft

ratronic · 2012-05-15 14:43

Cenlasoft in the code you posted I think it does what you want but gets immediatly erased by the repeat loop in the Go method. Try commenting out all of the instructions after the repeat in the Go method and see what values are returned.

Duane Degn · 2012-05-15 14:46

Next will only skip the remainder of the present loop. The loop will then continue again at the top of the loop. It doesn't break out of the loop.

You'd use quit to break out of the loop.

You could also use return to stop the method you are presently in and return to the calling method.

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