20x2 Interrupts

D

Dave E

Senior Member
This seems to be the week for x2 interrupt questions.
I have a 20x2 (c.0) using these commands:
hintsetup %00000110
setintflags %00000110, %00000110

What happens is that the INTERRUPT: subroutine does not run until BOTH hint1 and hint2 pins have been activated. In this case they are set to activate when the pin goes from a high to a low.

I can press one button, wait a while then press the other button. The INTERRUPT: routine does not run until after both buttons have been pressed.
When running DEBUG, the proper flags are set depending on which button I press.
Press button connected to hint1--flag register changes to %00001010
Press button connected to hint2--flag register changes to %00001100

However, only when the flag register = %00001110 does the INTERRUPT: routine run. Is this correct?

Below is the guts of my code:
All I am doing is counting and printing to an LCD.
After an Interrupt, the LCD should display wether the interrupt was from hint1 or hint2.

Code: 
HINTSETUP %00000110	'MAKE B.0 OR B.1 GO HIGH TO LOW TO INTERRUPT
SETINTFLAGS %00000110,%00000110
'-------------------------- MAIN --------------------------
DO
	SEROUT LCD, BAUD, (128, #WORK)
	WORK = WORK + 1
	DEBUG
LOOP

'-------------------------- SUBROUTINES -------------------
INTERRUPT:
DEBUG
	IF HINT1FLAG = 1 THEN
		SEROUT LCD, BAUD, (148, "HINT1")
	ENDIF
	IF HINT2FLAG = 1 THEN
		SEROUT LCD, BAUD, (168, "HINT2")
	ENDIF
	PAUSE 2000
	SEROUT LCD, BAUD, (148, "     ")
	SEROUT LCD, BAUD, (168, "     ")

	HINT1FLAG = 0
	HINT2FLAG = 0
	HINTFLAG = 0
	HINTSETUP %00000110
	SETINTFLAGS %00000110,%00000110
DEBUG
RETURN
Any input would be appreciated.

Dave E
 
Last edited:
I

inglewoodpete

Senior Member
I suspect you need to read up on SetIntFlags NOT <flags>, <mask>

The NOT configuration can trigger on 1 or another input state rather than both at once.
 
hippy

hippy

Technical Support
Staff member
What you are trying to do is interrupt when either pin goes low, so rather than interrupt on hint1flag and/or hint2flag you need to interrupt on the hintflag. This should work -

HIntSetup %00000110
SetIntFlags %00001000, %00001000

In the interrupt routine you would then check hint1flag and hint2flag to determine which caused the interrupt.

Code: 
Interrupt:
  hintflag = 0
  If hint1flag = 1 Then
    SerTxd( "INT1 ")
    hint1flag = 0
  End If
  If hint2flag = 1 Then
    SerTxd( "INT2 ")
    hint2flag = 0
  End If
  SetIntFlags %00001000, %00001000
  Return
Added : Works for me on a PICAXE-20X2.
 
Last edited:
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