Hall effect and interupt.

[shamu]

Hi all.
I am in the process of making a POV display, a rotating Hall effect switch triggers the sequence when it passes by a magnet.
The code checks the state of the Hall input using an 'If' statement at the start of a loop, the problem is that unless the Hall switch is triggered at the same instant as the 'If' statement is executed then the sequence doesn't start, can an interupt be used in some way?

Thanks.

[B]main:

#picaxe 40X2
#no_data


let dirsA = %11111111  ' Set port A as all outputs.
let dirsB = %11111111  ' Set port B as all outputs.
let dirsD = %11111111  ' Set port D as all outputs.




SYMBOL Delay = 300


  high C.1 'Blue when high.
  low C.5 'Red when high.



start:
  
 'let outpinsD = %11111111 'Turns all port D pins off
 'let outpinsA = %11111111 'Turns all port D pins off
  
  
  
If pinc.2=0 Then 'Responds to a Hall Effect switch when connected to pin 17
    let outpinsD =%11111111
 
  
  ' The 2 of 12
  '         128 64 32 16 8 4 2 1 
  
  let outpinsA =%10011100
  let outpinsA =%10111100
  let outpinsA =%10111110
  let outpinsA =%01111110
  let outpinsA =%01111010
  let outpinsA =%11100010
  let outpinsA =%10001110
  let outpinsA =%11111110  
  
  ' This is the gap before 1.
  let outpinsA =%11111111
 
  let outpinsA =%11111111
  let outpinsA =%11111111
  let outpinsA =%11111111
  let outpinsA =%11111111
  let outpinsA =%11111111  
  
  
  
   ' 1 for one o'clock
  '         128 64 32 16 8 4 2 1 
  
  let outpinsA =%00001111
  let outpinsA =%00011111
  let outpinsA =%11001111
  let outpinsA =%11100111
  let outpinsA =%11110011
  let outpinsA =%11110011
  let outpinsA =%11111010
  let outpinsA =%11111010  
  let outpinsA =%11111001  
  let outpinsA =%11111011
  
  
' This is the gap before 2.
  let outpinsA =%11111111
 
  let outpinsA =%11111111
  let outpinsA =%11111111
  let outpinsA =%11111111
  let outpinsA =%11111111
  let outpinsA =%11111111    
  
  
  
  ' 2 for two o'clock.
  '         128 64 32 16 8 4 2 1 
  let outpinsA =%10001111
  let outpinsA =%10111111
  let outpinsA =%00111111
  let outpinsA =%10111111
  let outpinsA =%11011111
  let outpinsA =%11101111
  let outpinsA =%11110111
  let outpinsA =%11111001  
  let outpinsA =%11111101  
  let outpinsA =%11111011  
  let outpinsA =%11110111  
  let outpinsA =%11101111  
  
  
  
  
  
  
  
  
  
 let outpinsA =%11111111

  




    
Else
  low C.1 'Blue when high.
  high C.5 'Red when high.
  
  let outpinsA =%11111111
  let outpinsB =%11111111
  let outpinsD =%00000000
  
End If




goto start

[/B]

 

[Buzby]

You need to wait for the trigger to change state :

Do
	do 
	' Waiting for pin to go High
	loop until pinc.2=1	
	
	do
	' Waiting for pin to go Low
	loop until pinc.2=0
	
	'
	' Put main code here
	'

	
Loop

 

[shamu]

Thanks, I'll give this a go!

 

[headingwest]

Hall effect - setint

Hi Shamu, have you looked at the setint command? This will trigger an interrupt when a pin is triggered. It checks between every command so is more likely to get noticed and you can keep running the rest of your code.

http://www.picaxe.com/BASIC-Commands/Interrupts-and-Multi-Tasking/setint/