Change On Interrupt, PIC16F884

[elec_mech]

Bruce,

Thank you! I completely forgot about bank switching! Here is the revised code if it helps anyone. I assume I don't need to worry about bank switching for the config settings.

INCLUDE "modedefs.bas"
PORTA = $00 ' Set all port a pins to low
PORTB = $00 ' Set all port b pins to low
PORTC = $00 ' Set all port c pins to low
PORTD = $00 ' Set all port d pins to low
PORTE = $00 ' Set all port e pins to low

asm ; The following code is assembly, not Basic
__CONFIG _CONFIG1, _INTOSCIO & _WDT_OFF & _PWRTE_ON & _CP_OFF & _BOR_OFF & _IESO_OFF & _FCMEN_OFF & _LVP_OFF
; Use internal oscillator & make both, OSC pins I/Os, turn off watchdog timer, enable Power-up timer,
; code protection off, brown-out off, disable switch over mode, turn off failsafe monitor,
; low voltage programming off
endasm ' End assembly code

ADCON0.0 = 0 ; Make all analog pins digital I/Os
CM1CON0.7 = 0 ; Disable comparator C1
CM2CON0.7 = 0 ; Disable comparator C2
OSCCON.6 = 1 ; Set the internal oscillator to 8MHz
OSCCON.5 = 1 ; Set the internal oscillator to 8MHz
OSCCON.4 = 1 ; Set the internal oscillator to 8MHz
WDTCON.0 = 0 ; Disable the watchdog timer
ANSEL = %00000000 ; Set all analog pins on port a to digital I/O
ANSELH = %00000000 ; Set all analog pins on port b to digital I/O

define OSC 8 ' Tell the program the oscillator is running at 8 MHz
TRISA = %00000000 ' Make all port a pins outputs
TRISB = %00001111 ' Make port b pins 0-3 inputs and the rest as outputs
TRISC = %00000000 ' Make all port c pins outputs
TRISD = %00000000 ' Make all port d pins outputs
TRISE = %00000000 ' Make all port e pins outputs
PORTA = $00 ' Set all port a pins to low
PORTB = $00 ' Set all port b pins to low
PORTC = $00 ' Set all port c pins to low
PORTD = $00 ' Set all port d pins to low
PORTE = $00 ' Set all port e pins to low
'Variables**************************************** ************************************************** *
b0 VAR byte ' Required byte variable for toggle button
'************************************************* ************************************************** *
INITIALIZE: ' Initialize Routine
INTCON.0 = 0 ' Clear the interrupt-on-change flag
On Interrupt goto Halt ' Once an active interrupt port is enabled, go to the Halt routine
INTCON.7 = 1 ' Enable global interrupts
IOCB = %00000001 ' Enable interrupt-on-change on RB0-RB3
INTCON.3 = 1 ' Enable interrupt-on-change on Port b
GOTO MAIN ' Go to Main routine
'************************************************* ************************************************** *
MAIN:
' PORTB = $00 ' Set all port b pins to low
b0 = PORTB ' temp is some variable
HIGH PORTE.0
PAUSE 500
LOW PORTE.0
PAUSE 500
GOTO MAIN
'************************************************* ************************************************** ***
DISABLE ' Disable all interrupts
Halt: ' Halt Routine
HIGH PORTE.1
LOW PORTE.0
b0 = PORTB ' temp is some variable
INTCON.0 = 0 ' Clear the interrupt-on-change flag
RESUME Done ' Go to Main routine
ENABLE ' Enable all active interrupts
'************************************************* ************************************************** ***
Done:

END

[Bruce]

This can cause a lot of headaches sometimes due to read-modify-write;

HIGH PORTE.1 ' reads whole port, flips this bit, writes whole port
LOW PORTE.0 ' same, but if RE1 isn't high yet, RE1 is read & writen back as 0

Try just toggling the LED on RE1 to verify that you're entering the interrupt routine.

Another potential show-stopper is directing RESUME to Done, which halts everything.

Try something like this;

INITIALIZE:  ' Initialize Routine
    IOCB = %00000001   ' Enable interrupt-on-change on RB0
    INTCON = %10001000 ' Global & interrupt-on-change on Port b enabled
'************************************************* 
On Interrupt goto Halt ' on interrupt go to the Halt routine

MAIN:
    HIGH PORTE.0
    PAUSE 500
    LOW PORTE.0
    PAUSE 500
    GOTO MAIN
'************************************************* 
    DISABLE       ' do NOT place interrupt checking code below
Halt:             ' Halt Routine
    WHILE PORTB.0=0 ' wait for button release & end mismatch condition on portb 
    WEND          
    TOGGLE PORTE.1
    INTCON.0 = 0  ' Clear the interrupt-on-change flag
    RESUME        ' Go to Main routine
    ENABLE        ' Enable all active interrupts

[elec_mech]

Bruce,

Thank you. It acts a little flaky, e.g., sometimes the LED on porte.1 would stay on two consecutive button presses or off, due to debounce. I looked at some other threads and found a 50ms pause. Here is the code again with the debounce which is working like a charm. Thank you for your help.

INCLUDE "modedefs.bas"
PORTA = $00 ' Set all port a pins to low
PORTB = $00 ' Set all port b pins to low
PORTC = $00 ' Set all port c pins to low
PORTD = $00 ' Set all port d pins to low
PORTE = $00 ' Set all port e pins to low

asm ; The following code is assembly, not Basic
__CONFIG _CONFIG1, _INTOSCIO & _WDT_OFF & _PWRTE_ON & _CP_OFF & _BOR_OFF & _IESO_OFF & _FCMEN_OFF & _LVP_OFF
; Use internal oscillator & make both, OSC pins I/Os, turn off watchdog timer, enable Power-up timer,
; code protection off, brown-out off, disable switch over mode, turn off failsafe monitor,
; low voltage programming off
endasm ' End assembly code

ADCON0.0 = 0 ; Make all analog pins digital I/Os
CM1CON0.7 = 0 ; Disable comparator C1
CM2CON0.7 = 0 ; Disable comparator C2
OSCCON.6 = 1 ; Set the internal oscillator to 8MHz
OSCCON.5 = 1 ; Set the internal oscillator to 8MHz
OSCCON.4 = 1 ; Set the internal oscillator to 8MHz
WDTCON.0 = 0 ; Disable the watchdog timer
ANSEL = %00000000 ; Set all analog pins on port a to digital I/O
ANSELH = %00000000 ; Set all analog pins on port b to digital I/O

define OSC 8 ' Tell the program the oscillator is running at 8 MHz
TRISA = %00000000 ' Make all port a pins outputs
TRISB = %00001111 ' Make port b pins 0-3 inputs and the rest as outputs
TRISC = %00000000 ' Make all port c pins outputs
TRISD = %00000000 ' Make all port d pins outputs
TRISE = %00000000 ' Make all port e pins outputs
PORTA = $00 ' Set all port a pins to low
PORTB = $00 ' Set all port b pins to low
PORTC = $00 ' Set all port c pins to low
PORTD = $00 ' Set all port d pins to low
PORTE = $00 ' Set all port e pins to low
'Variables**************************************** ************************************************** *
b0 VAR byte ' Required byte variable for toggle button
'************************************************* ************************************************** *
INITIALIZE: ' Initialize Routine
INTCON.0 = 0 ' Clear the interrupt-on-change flag
On Interrupt goto Halt ' Once an active interrupt port is enabled, go to the Halt routine
INTCON = %10001000 ' Enable global interrupts, Enable interrupt-on-change on Port b
IOCB = %00000001 ' Enable interrupt-on-change on RB0-RB3
PORTE.1 = 0 ' Make sure LED on PORTE.1 is off
GOTO MAIN ' Go to Main routine
'************************************************* ************************************************** *
MAIN:
HIGH PORTE.0
PAUSE 500
LOW PORTE.0
PAUSE 500
GOTO MAIN
'*************************************************
DISABLE ' do NOT place interrupt checking code below
Halt: ' Halt Routine
WHILE PORTB.0=0 ' wait for button release & end mismatch condition on portb
WEND
PAUSE 50 ' Debounce delay
TOGGLE PORTE.1 ' Toggle LED on PORTE.1
INTCON.0 = 0 ' Clear the interrupt-on-change flag
RESUME ' Go to Main routine
ENABLE ' Enable all active interrupts

[elec_mech]

One more question: How about detecting multiple switches with interrupt-on-change? I've tried the modified code below as well as the commented out code on its own. This works, but not reliably. I'm using those momentary red square switches from RadioShack and the LEDs only change about half the time, i.e., the program isn't detecting the button press. I've tried pressing the switches hard (fully down) quickly, but with the same hit rate of half. If I press and hold each button for a second or two, it works fine, but I don't want to force the user to press and hold a switch to do something. I tried playing with the debounce times and even adding a ceramic capacitor, 0.1uF and 0.01uF across the switch contacts with no luck. I tried searching the forum, but the only interrupt examples I've come across are for single button applications. Any suggestions?

INCLUDE "modedefs.bas"
PORTA = $00 ' Set all port a pins to low
PORTB = $00 ' Set all port b pins to low
PORTC = $00 ' Set all port c pins to low
PORTD = $00 ' Set all port d pins to low
PORTE = $00 ' Set all port e pins to low

asm ; The following code is assembly, not Basic
__CONFIG _CONFIG1, _INTOSCIO & _WDT_OFF & _PWRTE_ON & _CP_OFF & _BOR_OFF & _IESO_OFF & _FCMEN_OFF & _LVP_OFF
; Use internal oscillator & make both, OSC pins I/Os, turn off watchdog timer, enable Power-up timer,
; code protection off, brown-out off, disable switch over mode, turn off failsafe monitor,
; low voltage programming off
endasm ' End assembly code

ADCON0.0 = 0 ; Make all analog pins digital I/Os
CM1CON0.7 = 0 ; Disable comparator C1
CM2CON0.7 = 0 ; Disable comparator C2
OSCCON.6 = 1 ; Set the internal oscillator to 8MHz
OSCCON.5 = 1 ; Set the internal oscillator to 8MHz
OSCCON.4 = 1 ; Set the internal oscillator to 8MHz
WDTCON.0 = 0 ; Disable the watchdog timer
ANSEL = %00000000 ; Set all analog pins on port a to digital I/O
ANSELH = %00000000 ; Set all analog pins on port b to digital I/O

define OSC 8 ' Tell the program the oscillator is running at 8 MHz
TRISA = %00000000 ' Make all port a pins outputs
TRISB = %00001111 ' Make port b pins 0-3 inputs and the rest as outputs
TRISC = %00000000 ' Make all port c pins outputs
TRISD = %00000000 ' Make all port d pins outputs
TRISE = %00000000 ' Make all port e pins outputs
PORTA = $00 ' Set all port a pins to low
PORTB = $00 ' Set all port b pins to low
PORTC = $00 ' Set all port c pins to low
PORTD = $00 ' Set all port d pins to low
PORTE = $00 ' Set all port e pins to low
'Variables**************************************** ************************************************** *
b0 VAR byte ' Required byte variable for toggle button
'************************************************* ************************************************** *
INITIALIZE: ' Initialize Routine
INTCON.0 = 0 ' Clear the interrupt-on-change flag
On Interrupt goto Halt ' Once an active interrupt port is enabled, go to the Halt routine
INTCON = %10001000 ' Enable global interrupts, Enable interrupt-on-change on Port b
IOCB = %00000011 ' Enable interrupt-on-change on RB0-RB3
PORTE.1 = 0 ' Make sure LED on PORTE.1 is off
PORTE.2 = 0 ' Make sure LED on PORTE.2 is off
GOTO MAIN ' Go to Main routine
'************************************************* ************************************************** *
MAIN:
HIGH PORTE.0
PAUSE 500
LOW PORTE.0
PAUSE 500
GOTO MAIN
'*************************************************
DISABLE ' do NOT place interrupt checking code below
Halt: ' Halt Routine
IF PORTB.0 = 0 THEN
WHILE PORTB.0=0 ' wait for button release & end mismatch condition on portb
WEND
PAUSE 20 ' Debounce delay
HIGH PORTE.1
LOW PORTE.2
ENDIF
IF PORTB.1 = 0 THEN
WHILE PORTB.1=0 ' wait for button release & end mismatch condition on portb
WEND
PAUSE 20 ' Debounce delay
LOW PORTE.1
HIGH PORTE.2
ENDIF

' IF PORTB.0 = 0 THEN
' ' PAUSE 20
' ' IF PORTB.0 = 0 THEN
' HIGH PORTE.1
' LOW PORTE.2
' ' ENDIF
' ENDIF
'
' IF PORTB.1 = 0 THEN
' ' PAUSE 20
' ' IF PORTB.1 = 0 THEN
' LOW PORTE.1
' HIGH PORTE.2
' ' ENDIF
' ENDIF

INTCON.0 = 0 ' Clear the interrupt-on-change flag
RESUME ' Go to Main routine
ENABLE ' Enable all active interrupts

[Pic_User]

Hi elec_mech,
Posting code directly into the text portion of the forum makes it difficult to follow.

[code] paste your code here [/code]

One step better but a lot more work:

Show us your Colors.

define osc 8 ' tell the program the oscillator is running at 8 mhz

4.16. DEFINE may be used to change the predefined oscillator value...
These definitions must be in all upper case, exactly as shown.
If not, the compiler may not recognize them.
No error message will be produced for defines the compiler does not recognize.

DEFINE OSC 8

-Adam-

[elec_mech]

Adam,

I see what you mean with the DEFINE, oops! Thanks for the catch. I see what you mean with colors. Is this better?

INCLUDE "modedefs.bas"
PORTA = $00 ' Set all port a pins to low
PORTB = $00 ' Set all port b pins to low
PORTC = $00 ' Set all port c pins to low
PORTD = $00 ' Set all port d pins to low
PORTE = $00 ' Set all port e pins to low

asm ; The following code is assembly, not Basic
__CONFIG _CONFIG1, _INTOSCIO & _WDT_OFF & _PWRTE_ON & _CP_OFF & _BOR_OFF & _IESO_OFF & _FCMEN_OFF & _LVP_OFF
; Use internal oscillator & make both, OSC pins I/Os, turn off watchdog timer, enable Power-up timer,
; code protection off, brown-out off, disable switch over mode, turn off failsafe monitor,
; low voltage programming off
endasm ' End assembly code

ADCON0.0 = 0 ; Make all analog pins digital I/Os
CM1CON0.7 = 0 ; Disable comparator C1
CM2CON0.7 = 0 ; Disable comparator C2
OSCCON.6 = 1 ; Set the internal oscillator to 8MHz
OSCCON.5 = 1 ; Set the internal oscillator to 8MHz
OSCCON.4 = 1 ; Set the internal oscillator to 8MHz
WDTCON.0 = 0 ; Disable the watchdog timer
ANSEL = %00000000 ; Set all analog pins on port a to digital I/O
ANSELH = %00000000 ; Set all analog pins on port b to digital I/O

DEFINE OSC 8 ' Tell the program the oscillator is running at 8 MHz
TRISA = %00000000 ' Make all port a pins outputs
TRISB = %00001111 ' Make port b pins 0-3 inputs and the rest as outputs
TRISC = %00000000 ' Make all port c pins outputs
TRISD = %00000000 ' Make all port d pins outputs
TRISE = %00000000 ' Make all port e pins outputs
PORTA = $00 ' Set all port a pins to low
PORTB = $00 ' Set all port b pins to low
PORTC = $00 ' Set all port c pins to low
PORTD = $00 ' Set all port d pins to low
PORTE = $00 ' Set all port e pins to low
'Variables**************************************** ************************************************** *
b0 VAR byte ' Required byte variable for toggle button
'************************************************* ************************************************** *
INITIALIZE: ' Initialize Routine
INTCON.0 = 0 ' Clear the interrupt-on-change flag
On Interrupt goto Halt ' Once an active interrupt port is enabled, go to the Halt routine
INTCON = %10001000 ' Enable global interrupts, Enable interrupt-on-change on Port b
IOCB = %00000011 ' Enable interrupt-on-change on RB0-RB3
PORTE.1 = 0 ' Make sure LED on PORTE.1 is off
PORTE.2 = 0 ' Make sure LED on PORTE.2 is off
GOTO MAIN ' Go to Main routine
'************************************************* ************************************************** *
MAIN:
HIGH PORTE.0
PAUSE 500
LOW PORTE.0
PAUSE 500
GOTO MAIN
'*************************************************
DISABLE ' do NOT place interrupt checking code below
Halt: ' Halt Routine
IF PORTB.0 = 0 THEN
WHILE PORTB.0=0 ' wait for button release & end mismatch condition on portb
WEND
PAUSE 20 ' Debounce delay
HIGH PORTE.1
LOW PORTE.2
ENDIF
IF PORTB.1 = 0 THEN
WHILE PORTB.1=0 ' wait for button release & end mismatch condition on portb
WEND
PAUSE 20 ' Debounce delay
LOW PORTE.1
HIGH PORTE.2
ENDIF

' IF PORTB.0 = 0 THEN
' ' PAUSE 20
' ' IF PORTB.0 = 0 THEN
' HIGH PORTE.1
' LOW PORTE.2
' ' ENDIF
' ENDIF
'
' IF PORTB.1 = 0 THEN
' ' PAUSE 20
' ' IF PORTB.1 = 0 THEN
' LOW PORTE.1
' HIGH PORTE.2
' ' ENDIF
' ENDIF

INTCON.0 = 0 ' Clear the interrupt-on-change flag
RESUME ' Go to Main routine
ENABLE ' Enable all active interrupts

[Pic_User]

Adam,
I see what you mean with the DEFINE, oops! Thanks for the catch. I see what you mean with colors. Is this better?

It is better! But the idea is to copy from your editor, paste into a code box. So the indents and formatting look more like the original. Sometimes the forum changes the formatting. I was not sure the lowercase define was in your original or being changed by the forum. It changes a lot of things “for you” I wish I knew more about PBP to really help you on your real question.
-Adam-