Interrupt RPM and Taylors Elapsed time on 18F4620

[Darrel Taylor]

I thought that Proteus dealt with many versions of compilers except PBP.

Currently, you can only simulate the .hex files directly in Proteus.
No single stepping through the program.

But you can use it as a debugger in MPLAB where you can single step and watch variables in PBP.
It's too slow for me that way though. It simulates in "Real-Time" when not animating.

It's like real hardware is sitting in front of you, only you can't create Smoke or Fry your chips.
I'm getting hooked on it.

It's just so nice not to have to build a breadboard to test things.
20 minutes, and you can draw it on the computer.

Plus, with the Logic Analyzer, O-Scope, I2C debugger etc.
It saves thousands on test equipment.

And my cats can't play with the wires.
<br>

[Bruce]

Darrel,

Are you using the free or full version?

[Darrel Taylor]

Using the Full version.

The free version doesn't let you draw your own circuits.
<br>

[Tobias]

Thanks for the help on getting the RPM working right.

Next question, when I want to incorporate this into other code how do I keep it from taking up as much time as just measuring the pulse width with Pulsin? I can't have it in the little CaptureLoop routine waiting for the next rpm pulse.

Looking through the spec sheet on the 4620, I see CCP1IE (PIE1.2). If I enable that bit, will I get an interrupt on each cylinder fire? I know there is a way to start and stop timer1 based on the cylinder firing and not just looping for the cylinder firing.

Here is what I am working on assuming that is the right path to take. I haven't worked with interrupts much so I am sure I need more work.

DEFINE OSC 20
Prefix          con     $FE           ' needed before each command
LcdCls          CON     $51           ' clear LCD (use PAUSE 5 after)
CursorPS        con     $45           'Cursor Position
Capture         VAR     PIR1.2		    ' CCP1 capture flag CCP1IF
Overflow        VAR     PIR1.0	    	' Timer1 overflow flag TMR1IF:
RPM             var     word
period          var     Word
TotalTime       var     word      'Holds seconds and tics 
Counter         var     word
Detect          var     bit
LCD             VAR     PortC.6    'LCD output

 
ADCON0 =0       'A/D Off
ADCON1.3=1      'All AN channels digital
ADCON1.2=1      '''
ADCON1.1=1      '''
ADCON1.0=1      '''
TRISE.0=1       'EO input
TRISE.1=1       'E1 input
CCP1CON = %00000110  ; Capture mode, every rising edge 0101 , Fourth 0110
T1CON.7=1     'enable timer  16 bit `   
T1CON.6=1     'Timer1 OSC
T1CON.5=1     '1:4 prescaler
T1CON.4=0     '1:4 prescaler
T1CON.3=0     'Timer1 OSC off
T1CON.2=0     'sychro clock
T1CON.1=0     'internal clock
T1CON.0=0     'stop timer
PIE1.2=1      'Enables the CCP1 interrupt

pause 10
SEROUT2 LCD,84, [Prefix, LcdCls]

Include "modedefs.bas"	' Mode definitions for Serout
SEROUT2 LCD,84, [Prefix,CursorPS,0,"RPM test"]
pause 500

TMR1H = 0    'Clear 8-bit register                              
TMR1L = 0    'Clear 8-bit register
capture = 0  'Clear Timer
Detect = 0

ON Interrupt goto Measure_Time

Loop:
  Counter = Counter + 1
  SEROUT2 LCD,84, [Prefix,CursorPS,0,dec5 Counter]
  SEROUT2 LCD,84, [Prefix,CursorPS,20,"RPM ",dec5 RPM, " ", #Detect]
goto loop

Disable
Measure_Time:
SEROUT2 LCD,84, [Prefix,CursorPS,40,"Int ",dec5 RPM]
If Detect = 0  then
  T1CON.0=1
  detect = 1
  capture = 0
endif

If Detect = 1  then
  T1CON.0=0
  detect = 0 
  period.LowByte=CCPR1L
  period.HighByte=CCPR1H
  capture = 0
  TMR1H = 0
  TMR1L = 0
  
  RPM = 10000
  RPM = RPM * RPM ' 100,000,000
  RPM = DIV32 period ' 100,000,000 / RevCount
  RPM = RPM * 60 ' Per minute
  RPM = DIV32 1600
  RPM = (RPM*5)
endif
Enable
return

[HTML][/HTML]

[rmteo]

See here Using hardware capture

[Tobias]

Thanks for the link. The thing is though I don't want to go into a loop waiting for the tach pulse. I want to be able to do it by interrupt so I can be doing other things in between pulses and on the pulse go start/stop the timer.

[rmteo]

Look at post #9. This is its main loop:

Main:
  ' do other stuff here as required
  IF CF.0 THEN         ' figure out & print result only after last capture
    PW = PW-T1         ' High pulse width = PW-T1
    CF.0 = 0           ' clear flag bit
    HSEROUT [DEC PW,"uS High",13,10]
  ENDIF
  
  GOTO Main