Hall effect sensor code critique wanted

turbosupra · 2010-10-14 21:29

I'd like a second, third or tenth set of eyes to give these functions a quick glance over and see if there are any holes. I'm not the most efficient code writer by any means, but I would like to see if there are any holes in functionality.

This is for a 36-2 trigger wheel and hall effect sensor on an automobile.

Thanks for reading.

CON

  _clkmode = xtal1 + pll16x
  _xinfreq = 5_000_000

  c_CrankSensorInputPin         = 1
  c_KeyOnInputPin               = 2
  c_CamSensorInputPin           = 3
  c_CrankSensorOutputPin        = 5
  c_CamSensorOutputPin          = 7
  c_ECUFeedbackPin              = 8





OBJ

  Debug : "FullDuplexSerial"      




VAR



  ' ########### PUB Main Variables ###########


  ' ########### CalculateRPMs Variables ###########
  
        long RPMCalculator
        long c_WaitingforKeyOn
        long CrankToothSyncCount
        long SyncPulseLow
        long SyncPulseHigh
        long SyncPulseHighTime1
        long SyncPulseHighTime2
        long c_WaitingtoSyncPulses
        long SyncTimeBetweenPulses
        long c_WaitingtoSyncTDC
        long CrankToothCount
        long TDCSynced
        long CrankToothPulseTime
        long CrankToothTDC
        long cranksensorlow
        long CrankTDCTime
        long c_CountingCrankTeeth
        long cranksensorhigh
        long CrankTimeBetweenTriggerTeeth
        long CrankTDC
        long CrankTimeBetweenTDCs
 
        


  ' ########### RPMfromCrankTrigger  Variables ###########
  
        long RPMfromCT
        


  ' ########### RPMfromTopDeadCenter Variables ###########

        long RPMfromTDC






PUB CalculateRPMs

  dira[c_CrankSensorInputPin]   := 0
  dira[c_KeyOnInputPin]   := 0
  dira[c_CamSensorInputPin]   := 0



  repeat
  
    case RPMCalculator

      c_WaitingforKeyOn:

        If c_KeyOnInputPin == 1                                                 ' If the key is on
          CrankToothSyncCount := 0
          SyncPulseLow := true
          SyncPulseHighTime1 := 0
          SyncPulseHighTime2 := 0
          RPMCalculator := c_WaitingtoSyncPulses
          'RPMCalculator := c_WaitingtoSyncTDC
        

        else
          RPMCalculator := c_WaitingforKeyOn
          Debug.Str(string("Key is off"))
          Debug.Tx(13)


      c_WaitingtoSyncPulses:
      
        If c_CrankSensorInputPin == 1 AND SyncPulseLow := true                  ' Initially set to low

          If SyncPulseHighTime1 <> 0 AND SyncPulseHighTime2 == 0
            SyncPulseHighTime2 := cnt
            SyncPulseLow := false
            SyncTimeBetweenPulses := (SyncPulseHighTime2 - SyncPulseHighTime1)  ' If rpms are at 200 and not TDC, variable is set to 0.00833333333333 . If at TDC variable is set to 0.0166666666667 
            RPMCalculator := c_WaitingtoSyncTDC
                    
          Elseif SyncPulseHighTime1 == 0                                        ' First time entering the loop when pin sees a high
            SyncPulseHighTime1 := cnt
            SyncPulseHigh := true
            SyncPulseLow := false
            'RPMCalculator := c_WaitingtoSyncPulses                             ' Jumps out of the if statement so the following elseif will not evaluate to true in this single loop
                      
          Else
            Debug.Str(string("WaitingtoSyncPulses Error"))
            Debug.Tx(13)  

        Elseif c_CrankSensorInputPin == 0
          SyncPulseLow := true

        Else  
          Debug.Str(string("Waiting to transistion"))
          Debug.Tx(13)
          
          
                                                        ' 200rpms is a tooth pulse every 0.00833333333333  (* 1.75 = 0.0145833333333)
      c_WaitingtoSyncTDC:                               ' 400rpms is a tooth pulse every 0.00416666666667  (* 1.75 = 0.0072916666667)
                                                        ' 500rpms is a tooth pulse every 0.00333333333333  (* 1.75 = 0.0058333333333)
        If c_CrankSensorInputPin == 1 AND SyncTimeBetweenPulses =< 0.0145833333333    ' aka 200rpms when car starts to turn over and pin goes high

          If CrankToothSyncCount =< 34 AND SyncPulseLow == true                  ' starts at 0
          
            CrankToothSyncCount := CrankToothSyncCount + 1
            SyncPulseLow := false

          Elseif CrankToothSyncCount > 34 AND SyncPulseLow == true
            SyncPulseLow := false
            CrankToothSyncCount := 1                    ' when pin goes high a 35th time (which is also the first time during another revolution)
            CrankToothCount := 0
            TDCSynced := true
            CrankToothPulseTime := cnt
            CrankToothTDC := cnt
            cranksensorlow := true
            CrankTDCTime := cnt
            Debug.Str(string("----- TDC Sync ----- TDC Sync ----- Count Higher than 34 -----"))
            Debug.Tx(13)
            RPMCalculator := c_CountingCrankTeeth

          Else
            Debug.Str(string("Error in c_WaitingtoSyncTDC"))
            Debug.Tx(13) 
             
        Elseif c_CrankSensorInputPin == 1 AND SyncTimeBetweenPulses > 0.0145833333333
          CrankToothTDC := cnt
          CrankToothCount := 0 
          TDCSynced := true
          CrankToothPulseTime := cnt
          cranksensorlow := true
          CrankTDCTime := cnt
          Debug.Str(string("----- TDC Sync ----- TDC Sync -----"))
          Debug.Tx(13)
          RPMCalculator := c_CountingCrankTeeth

        Elseif c_CrankSensorInputPin == 0
          SyncPulseLow := true
        
          
        Else
          Debug.Str(string("Waiting to transition in c_WaitingtoSyncTDC"))
          Debug.Tx(13)
         

      c_CountingCrankTeeth:
      
        If c_CrankSensorInputPin == 1 AND cranksensorlow := true                ' when pin goes high after a low
          cranksensorhigh := true
          cranksensorlow := false
        
          If CrankToothCount =< 34
            CrankTimeBetweenTriggerTeeth := (cnt - CrankToothPulseTime)         ' time between last crank sensor pulse and this one
            CrankToothCount := CrankToothCount + 1
            CrankToothPulseTime := cnt

          Else 
            CrankToothCount := 1                                                ' 1 or 35, they are both the same
            CrankTDC := true
            CrankTimeBetweenTDCs := (cnt - CrankTDCTime)                        ' when pin goes high a 35 time (which is also the first time during another revolution)
            CrankTDCTime := cnt 
            Debug.Str(string("----- TDC ----- TDC -----"))
            Debug.Tx(13)


        elseif c_CrankSensorInputPin == 0
          cranksensorlow := true
          cranksensorhigh := false

        else  
          Debug.Str(string("Waiting for transition in CountingCrankTeeth"))
          Debug.Tx(13)







PUB RPMfromCrankTrigger

  repeat
  
    If c_CrankSensorInputPin == 1
      RPMfromCT := (((1/CrankTimeBetweenTriggerTeeth) * 36) * 60)
      If RPMfromCT =< 0 OR RPMfromCT => 10_000
        RPMfromCT := 0
        Debug.Str(string("Error in case RPMfromCrankTrigger"))
        Debug.Tx(13)
      Else
        RPMfromCT := RPMfromCT
        






PUB RPMfromTopDeadCenter 

  repeat
    If cranktdc == true
      RPMfromTDC := ((1/CrankTimeBetweenTDCs) * 60)  
      If RPMfromTDC =< 0 OR RPMfromTDC => 10_000
        RPMfromTDC := 0
        Debug.Str(string("Error in case RPMfromTopDeadCenter"))
        Debug.Tx(13)
      Else
        RPMfromTDC := RPMfromTDC

W9GFO · 2010-10-14 21:37

I think this will be a problem;

If c_CrankSensorInputPin == 1 AND SyncTimeBetweenPulses =< 0.0145833333333

Rich H

turbosupra · 2010-10-15 17:35

Hi Rich,

Thanks for the response, can you tell me why? How about the rest of it?

W9GFO wrote: »
I think this will be a problem;
If c_CrankSensorInputPin == 1 AND SyncTimeBetweenPulses =< 0.0145833333333
Rich H

P!-Ro · 2010-10-15 17:57

It needs to be an integer.

turbosupra · 2010-10-15 19:41

I feel like everyone else knows something I do not ... I'm not sure how I can make that value an integer?

I could write (116666/clkfreq) but I don't think that buys me anything?

As of now, I believe the value has to be 1.75 times the length of time between each tooth's pulse at a cranking rpm of 200. If this 1.75(value) is seen, that means that TDC is reached during the minus 2 of the 36-2 portion of the trigger wheel.

I'm going to humbly ask for a laymens term explanation, because I feel like I'm missing something?

P!-Ro · 2010-10-16 10:31

I'm no coding genius but I need to do something similar to this with my own robot, but the rpm's can be up to 5,000. With the prop, most of the calculations need to be done with integer math, although there are a few objects that can do floating point, just not quickly.

What I advise doing to keep it in integer is to multiply it by a factor of 10, so for example instead of 0.0145833333333, multiply it by 100,000 for 1,458. Then, if everything else follows through with a factor of 100,000 then instead of telling it to go the max speed of 200 rpm it would be multiplied by 100,000 to 200,000,000, but would be the equivalence of 200 rpm.

turbosupra · 2010-10-16 13:13

Thanks!

I think I have something working ... if I can test it and I get it working, I will send it to you in case you want to see what I've done.

P!-Ro wrote: »

I'm no coding genius but I need to do something similar to this with my own robot, but the rpm's can be up to 5,000. With the prop, most of the calculations need to be done with integer math, although there are a few objects that can do floating point, just not quickly.

What I advise doing to keep it in integer is to multiply it by a factor of 10, so for example instead of 0.0145833333333, multiply it by 100,000 for 1,458. Then, if everything else follows through with a factor of 100,000 then instead of telling it to go the max speed of 200 rpm it would be multiplied by 100,000 to 200,000,000, but would be the equivalence of 200 rpm.

Hall effect sensor code critique wanted

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