Interrupt On both (Rising and Falling)

[yasser hassani]

Thanks alot dear Acetronics.
I wrote this simple program for testing portB change interrupt.

'************************************************* ****************
'* LCD Deifnes *
'************************************************* ****************

DEFINE LCD_DREG PORTD ' I/O port where LCD is connected
DEFINE LCD_DBIT 4
DEFINE LCD_RSREG PORTD
DEFINE LCD_RSBIT 2 ' Register select pin
DEFINE LCD_EREG PORTD
DEFINE LCD_EBIT 3 ' Enable pin
DEFINE LCD_BITS 4 ' 4-bit data bus
DEFINE LCD_LINES 2 ' LCD has 2 character lines

'************************************************* ****************
'* Interrupt Initialzing *
'************************************************* ****************

INTCON = %10001000 ' GIE and RBIE are set
OPTION_REG = %10000000

'************************************************* ****************
'* Initialzation *
'************************************************* ****************

TRISB = %00010000
PORTB = 0

ON INTERRUPT GOTO DIRECTION

'************************************************* ****************
'* Main Program *
'************************************************* ****************

MAIN:
lcdout $fe,1
lcdout "Main Routine"
pause 500
GOTO MAIN
END

'************************************************* ****************
'* Interrupt Service Routine *
'************************************************* ****************

DISABLE
DIRECTION:
lcdout $fe,1
lcdout "Interrupt !!!"
PAUSE 100
INTCON.0 = 0
RESUME
ENABLE

I compiled it and downloaded HEX file to PIC. I use PROTEUS 6 pro for simulating my program.(My Circuit Attached) When I pushed start debugging button on
proteus an unusual thing happened. I think that program should work in main loop so "Main Routine" should be written on LCD! But as soon as program starts
executing, the message "Interrupt !!!" is shown on LCD!! even if the push button isn't pressed. Why it does not work correct?!!

You wrote for me: "... in a word, you have to READ PortB in your interrupt stubb to get it that interrupt working properly ( see examples given ...)" What do you maen? Could you tell me about given examples?
** Although I use PIC16F877 in this simulator, I want to use PIC16F84 in my project. **

[skimask]

Do you know what the inital value of port B is in order to detect a change on said port B?
Are all of your Port B pins pulled high/low or whatever?
Are any of them floating? open?

2nd thought...get rid of the simulator and build some real hardware...

[Acetronics2]

Hi, Yasser

I'll give a try on my test board : 16F84 + LCD ...

Alain

[Acetronics2]

Yasser,

You're a bad student !!!

What did I tell you about " mismatch condition " ???

	STATE 	var Byte
	I 		var Byte
	 	 
	PORTA = 0
	PORTB = 0
'************************************************* ****************
'* Interrupt Initialzing *
'************************************************* **************** 

INTCON     = %10001000 ' GIE and RBIE are set
OPTION_REG = %10000000

'************************************************* ****************
'* Initialzation *
'************************************************* ****************

PORTB = 0
TRISB = %00010000

ON INTERRUPT GOTO DIRECTION

'************************************************* ****************
'* Main Program *
'************************************************* ****************

MAIN:

lcdout $fe,1,"Main Routine"

FOR I = 1 to 50 : PAUSE 10 : NEXT I ' For quick response

GOTO MAIN
END

'************************************************* ****************
'* Interrupt Service Routine *
'************************************************* ****************

DISABLE

DIRECTION:

STATE = PORTB	' End of Mismatch Condition

lcdout $fe,1
lcdout "Interrupt !!!"

IF State.4 THEN

	LCDOUT $FE,$C0," LOW to HIGH "
	
ELSE

	LCDOUT $FE,$C0, " HIGH to LOW "
	
ENDIF
	
PAUSE 1000

INTCON.0 = 0

RESUME

ENABLE

END

That works fine ... for a 16F84 !

Alain

[yasser hassani]

Hi dearAcetronics.
Thanks alot for your replies. I found a nice PDF on the net about "Using the PORTB Interrupt on Change as an External Interrupt" microchip AN566. I rewote my code:

'************************************************* ****************
'* Initialzation *
'************************************************* ****************

TRISB = %00010000

'************************************************* ****************
'* Interrupt Initialzing *
'************************************************* ****************

OPTION_REG = %10000000
INTCON = %10001000
ON INTERRUPT GOTO DIRECTION

'************************************************* ****************
'* Main Program *
'************************************************* ****************

MAIN:
PAUSEUS 10
lcdout $fe,1
lcdout "Main Routine"
pause 100
GOTO MAIN
END

'************************************************* ****************
'* Interrupt Service Routine *
'************************************************* ****************

DISABLE
DIRECTION:
@ MOVF PORTB,1
INTCON.0 = 0
lcdout $fe,1
lcdout "Interrupt !!!"
PAUSE 100
RESUME
ENABLE
and it worked correct.

[Acetronics2]

Ok, you're fine now ...

and you also know how to show the transition way !!!

read you soon.

Regards

Alain