ISRTimer.bas problems

[richardb]

Sorry to ask again but i seem to be having an issue with the "ISRTimer.bas" module


this is clearly my lack of understanding but i hardly ever use timers.

Code: Select all

Event OnTimer()	
	TP1 = 1
	If Mscounter >= 1000 Then
		Mscounter=0
		TimePassedInMS=TimePassedInMS+1
		flowcounts = counter
		counter=0
	Else
	    Mscounter=Mscounter+1
	    If FlowIP_Last<>FlowIP Then
   			counter=counter+1
   			FlowIP_Last = FlowIP
		EndIf
	EndIf
   	TP1 = 0 
   	
   	
   	
   	
   	
Timer.Initialize
Timer.Items(0).Interval = 1      
Timer.Items(0).OnTimer = OnTimer  // timer event handler
Timer.Items(0).Enabled = true     // enable this timer
Timer.Start 


End Event

I realise I haven't posted everything, but If I use this code on its own it works just fine , it's for measuring a frequency between 1Hz and 400Hz, from a water flow meter.

but if i try to output the data via the comport i get the data corrupted occationally, the even only seems to run for approximately 2us. is it likely to be some kind of context saving issue ?


Rich

[Jerry Messina]

is it likely to be some kind of context saving issue ?

It could be, depending on if you're trying to format and send the data inside the timer event. I wouldn't recommend that.

Also, calling those timer setup routines (timer.initialize, timer,start) inside the timer event isn't a good idea.
The event runs inside the timer ISR and those routines re-enable interrupts. Not something likely to work out very well.
Once you're setup the timer in your main code the timer will run and periodically call your event automatically.

[richardb]

oops that was a copy and paste error i was just showing the interval. the flowcounts variable was being sent in the main code loop.

Code: Select all

Device = 18F47Q43
Clock = 64

Config
    FEXTOSC = OFF,      // Oscillator not enabled
    RSTOSC = HFINTOSC_64MHZ,// HFINTOSC with HFFRQ = 64 MHz and CDIV = 1:1
    CLKOUTEN = OFF     // CLKOUT function is disabled
    
    
    
Event OnTimer()	
	TP1 = 1
	If Mscounter >= 1000 Then
		Mscounter=0
		TimePassedInMS=TimePassedInMS+1
		flowcounts = counter
		counter=0
	Else
	    Mscounter=Mscounter+1
	    If FlowIP_Last<>FlowIP Then
   			counter=counter+1
   			FlowIP_Last = FlowIP
		EndIf
	EndIf
   	TP1 = 0 
End Event

   	
Timer.Initialize
Timer.Items(0).Interval = 1      
Timer.Items(0).OnTimer = OnTimer  // timer event handler
Timer.Items(0).Enabled = true     // enable this timer
Timer.Start 

that's everything in the event.

[Jerry Messina]

check your PM.