In SX Microcontrollers, SX/B Compiler and SX-Key Tool, jmokie wrote:

I have been fiddling with this problem for some time now without any success.  Please let me tap into your knowledge to help me out.
 

Problem:  

I have three optical sensors that I am trying to use for line following.  I have successfully connected them as a/d inputs to the SX28.  The outputs seem to have a reasonable relationship to the manufacture's curves.  I need to calculate max, min, and avg of each of the sensors in order to use their signals for PID control of the motors.

 

3 x 3 sensors = 9 variables.  Now when I use my method of noise reduction by taking the avg of 5 readings, I need 3 word variables( X 5 bytes and then divide by 5.) so that takes another 6 bytes of variable space.  I have reached the limit of variable memory space ( in order to do this, what with needing a few other variables for PVerror, Pulse widths, timers, etc.

 

My variable list and the subroutine that I am using are listed below.  I am a basic programmer and fairly new to SX28.  Any suggestions?

Jerry

-----------------------------------------

LMax var byte
LMin var byte
LAvg var byte                                    Left Sensor values
Lf var word   [for calculating avg]
Lval var byte [raw value from sensor]

------------------------------------------
RMax var byte
RMin var byte
RAvg var byte                                  Right sensor values
Rt var word   [for calculating avg]
Rval var byte  [raw value from sensor]

----------------------------------
Ctr var word    [for calculating avg]
CVal var byte   [raw value from sensor]
CMax var byte                                     Center sensor
CMin var byte
CAvg var byte

---------------------------------
timer var byte

 


Snsrread:
  timer = 0
   
  For timer = 0 to 5
   ANALOGIN InCPin, OutCPin, Cval, 2
   ANALOGIN InRPin, OutRPin, Rval, 2
   ANALOGIN InLPin, OutLPin, Lval, 2
 Ctr = Ctr + Cval
        Rt = Rt + Rval
 Lf = Lf + Lval
  next
  Ctr = Ctr/5     [calculate avg]
'---------------------------Calculate Min, Max, Avg of Ctr
  \mov Cval, Ctr lsb    [take the lsb to conserve on memory]
  If Cval < Cmin then
 Cmin=Cval
  endif
  If Cval>CMax then
 CMax=Cval
  endif
  CAvg=CMax+CMin
  CAvg=Cavg/2
  ------------------------------------
  Rt = Rt/5
  \mov Rval, Rt lsb    [same routine on each input]
  If Rval < Rmin then
 Rmin=Rval
  endif
  If Rval>RMax then
 RMax=Rval
  endif
  RAvg=RMax+RMin
  Ravg=Ravg/2

------------------------------------------
  Lf = Lf/5
  \mov Lval, Lf lsb
  If Lval < Lmin then
 Lmin= Lval
  endif
  If Lval>LMax then
 LMax= Lval
  endif
  LAvg=LMax+LMin
  lAvg=Lavg/2

   return

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