Using same button for entering/exiting some part of code?

Hello. This might sound simple, but I can't find the reliable solution.

Say I have button, input pin, which is tied to VDD via 10K resistor.
Pressing button pulls input pin down.

There is in some code, say code1, which runs in loop.
When user press button, execution goes to code2, which also runs in loop.
While in loop2, when user presses the button, execution is returned to code1

The issue is, if user keeps button pressed, the code will jump from code1 to code2 and back from code2 to code1.

To avoid this, the button state should be checked, so when user presses the button while in code1, jump to code2 will not occur until he releases the button.

I tried to use BUTTON statement, but it is not handy, since it only can do jump to label, and sometimes I just want to change value of some variable. And sometimes buttons are tied to ADC, so different button returns different ADC value.

Is there a simple way for fixing the issue I have?

I made a multi-function timer that deals with that and does different things according to how long sw is pressed ( and improved it to a touch sw using a/d)...... simply loops through routines using counts of pauses between sw presses.

part of sw press checks......

FOR B5= 1 TO 10 '.1 SECONDS FOR TIMER
PAUSE 6
if GPIO.1= 1 then start
NEXT B5

read 1,b6 :PAUSE 10: W0=60*B6:W1=W0
HIGH 4 ': HIGH 2

FOR B5 = 1 TO 100 '2 SECONDS FOR 6 HR
PAUSE 10
if GPIO.1=1 then TIMER
NEXT B5
W0=28800 '8 HRS
HIGH 2

You might do something like this:
Obvioulsy you can't have code that takes a long time to exectute in each section or you'll miss the button press. If that's the case, move the code that handles the button to a subroutine and call that routine multiple times from within the section(s) that takes the longest time.

Code:

---

ButtonPressed          CON 0
FirstPieceOfCode      CON 1
LastPieceOfCode        CON 3

CodeToRun              VAR BYTE
ButtonHasBeenPressed  VAR BIT

ChangeButton          VAR PortB.2

CodeToRun              = FirstPieceOfcode
ButtonHasBeenPressed  = 0

Main:

  If ChangeButton = ButtonPressed THEN
    ButtonHasBeenPressed = 1
  ENDIF

  IF (ButtonHasBeenPressed = 1) AND (ChangeButton <> ButtonPressed) THEN  ' But was pressed but is now released
    ButtonHasBeenPressed = 0
    CodeToRun = CodeToRun + 1            ' Advance to next code section
    If CodeToRun > LastPieceOfCode THEN  ' Wrap around and start over
      CodeToRun  = FirstPieceOfCode
    ENDIF
  ENDIF 


  Select Case CodeToRun

    Case 1
      'Some code
 
  Case 2
      'Some other code

    Case 3
      'Yet some other code

  END SELECT

Goto Main

---

This is not tested or even compiled so use it as an idea.

I think, there is some misunderstanding.

Here what I need

Code:

---

code1:
if button=0 then goto code2
'somecode here
goto code1

code2:
if button=0 then goto code1
'somecode here
goto code2

---

So all I need is when user presses the button in code1, execution won't jump to code2 until he releases the button. And same for code2.

The code I posted should do exactly with that, with the advantage that the section of code you're currently in will continue to run UNTIL you release the button. What you're proposing will HANG the current program section until you release the button. But here you go:

Code:

---

code1:
if button=0 then    'check if button is pressed
  PAUSE 5                      'allow some contact bounce
  WHILE button=0 : WEND  'wait for it to be released
  PAUSE 5                    'allow some contact bounce
  goto code2
ENDIF
'somecode here
goto code1

code2:
if button=0 then
  WHILE button = 0 : WEND
  goto code1
ENDIF
'somecode here
goto code2

---

and obviously, button is a reserved word.

Thanks!
No problem for code to "Hang", since this is for going from main menu to sub-menu and back.

my experience with button press usage is to have to wait for button release, can either stay in present routine and wait before switching OR moving to other routine and wait for release before looking for new press and going back.

Here is the practical code I'm using, but it sometimes behaves strangely.
Say, button was pressed, action was made once, user still holds button, so no advance in code. But when user releases the button, sometimes it acts as button was pressed once again. Any ideas how to fix it?

Code:

---

MENULOOP: 'MAIN CONFIG SCREEN
IF UPBT=0 THEN
MENUITEM=MENUITEM+1
IF MENUITEM>4 THEN MENUITEM=1
GOSUB CENTRAL
pause 200 'debounce
ENDIF
WHILE UPBT=0:WEND


IF DNBT=0 THEN
MENUITEM=MENUITEM-1
IF MENUITEM<1 THEN MENUITEM=4
GOSUB CENTRAL
pause 200 'debounce
ENDIF
WHILE DNBT=0:WEND
if menuitem=1 and rbut=0 then
pause 5
while rbut=0: wend
goto clockconfig
endif
GOTO MENULOOP

---

There does not seem to be any debounce on button release. Try

Code:

---

  IF UPBT=0 THEN
    MENUITEM = MENUITEM+1

    IF MENUITEM > 4 THEN MENUITEM = 1
    GOSUB CENTRAL
    ' PAUSE 20          ' May be needed if subroutine CENTRAL executes very fast.
    WHILE UPBT = 0 : WEND
    PAUSE 20 'debounce
  ENDIF

---

read switch a few times to be sure and debounce......

IF UPBT=0 THEN
PAUSE 20 ' or 40 or 50
IF UPBT=0 THEN 'go ahead........

MENUITEM = MENUITEM+1

do same for release check .... if upbt=1 then.....

For couple of buttons this code works fine, but when I increase number of button handling operations, some weird things occur - the further from beginning is the button handling routine, more rarely it responds to user.

The code below has 8 "blocks" of button handling.

first 3 work fine, 4th one works only maybe on 10 or 15th press. 5th and further - do not work at all.
And this is not issue of particular code - if I move say "5th block" to 1st place of this code, then it works fine.

PIC18F45K80 @64mhz.

Code:

---



IF UPBT=0 THEN
MENUITEM=MENUITEM+1
IF MENUITEM>6 THEN MENUITEM=1
pause 200
ENDIF
WHILE UPBT=0:WEND


IF DNBT=0 THEN
MENUITEM=MENUITEM-1
IF MENUITEM<1 THEN MENUITEM=6
pause 200
ENDIF
WHILE DNBT=0:WEND




IF LBUT=0 AND MENUITEM=2 THEN 
RICXVI=RICXVI+1
IF RICXVI>31 THEN RICXVI=1
pause 200
GOSUB SETTIME
ENDIF
WHILE LBUT=0:WEND


IF RBUT=0 AND MENUITEM=2 THEN 
RICXVI=RICXVI-1
IF RICXVI<1 THEN RICXVI=31
pause 200
GOSUB SETTIME
ENDIF
WHILE RBUT=0:WEND




IF LBUT=0 AND MENUITEM=1 THEN 
TVE=TVE+1
IF TVE>13 THEN TVE=1
pause 200
GOSUB SETTIME
ENDIF
WHILE LBUT=0:WEND


IF RBUT=0 AND MENUITEM=1 THEN 
TVE=TVE-1
IF TVE<1 THEN TVE=13
pause 200
GOSUB SETTIME
ENDIF
WHILE RBUT=0:WEND






IF LBUT=0 AND MENUITEM=3 THEN 
DGE=DGE+1
IF DGE>7 THEN DGE=1
pause 200
GOSUB SETTIME
ENDIF
WHILE LBUT=0:WEND


IF RBUT=0 AND MENUITEM=3 THEN 
DGE=DGE-1
IF DGE<1 THEN DGE=7
pause 200
GOSUB SETTIME
ENDIF
WHILE RBUT=0:WEND

---

I tried to reduce PAUSE 200 to 20 or even 2 - no change.

what about something like this instead?

Code:

---

IF UPBT=0 THEN
    MENUITEM=MENUITEM+1
    IF MENUITEM>6 THEN MENUITEM=1
    PAUSE 20
    WHILE UPBT=0:WEND
    PAUSE 20
ENDIF

IF DNBT=0 THEN
    MENUITEM=MENUITEM-1
    IF MENUITEM<1 THEN MENUITEM=6
    PAUSE 20
    WHILE DNBT=0:WEND
    PAUSE 20
ENDIF

IF LBUT=0 THEN
    IF MENUITEM=1 THEN 
        TVE=TVE+1
        IF TVE>13 THEN TVE=1
        GOSUB SETTIME
    ENDIF
    IF MENUITEM=2 THEN 
        RICXVI=RICXVI+1
        IF RICXVI>31 THEN RICXVI=1
        GOSUB SETTIME
    ENDIF
    IF MENUITEM=3 THEN 
        DGE=DGE+1
        IF DGE>7 THEN DGE=1
        GOSUB SETTIME
    ENDIF
   
    PAUSE 20
    WHILE LBUT=0:WEND
    PAUSE 20
ENDIF

IF RBUT=0 THEN
    IF MENUITEM=1 THEN 
        TVE=TVE-1
        IF TVE<1 THEN TVE=13
        GOSUB SETTIME
    ENDIF
    IF MENUITEM=2 THEN 
        RICXVI=RICXVI-1
        IF RICXVI<1 THEN RICXVI=31
        GOSUB SETTIME
    ENDIF
    IF MENUITEM=3 THEN 
        DGE=DGE-1
        IF DGE<1 THEN DGE=7
        GOSUB SETTIME
    ENDIF
   
    PAUSE 20
    WHILE RBUT=0:WEND
    PAUSE 20
ENDIF

---

it could be simplified even more, but...

You could create a bit Flag. When the Button is pressed, the Flag is toggled. When you get to a reasonable point in Code1 Routine, check your Flag. If it has toggled (is now a 1 for example), use GOTO to jump to Code2. Put "IF Flag = 0 THEN : GOTO Code1" in convenient spots throughout in Code2, etc.

debounce button check... and instead of while-wend .... use for/next pause here is 2 second check so if holding button > 2 seconds, can advance MENUitem then check again for release


HERE:
IF UPBT=0 THEN
pause 50
IF UPBT=0 THEN ..............................#debounce check
MENUITEM=MENUITEM+1
IF MENUITEM>6 THEN MENUITEM=1
PAUSE 20

for a=1 to 20
pause 50................................................ ............# if 2 second press, advance item and wait again
IF UPBT=1 THEN ---leave to somewhere .................# XXXXX WHILE UPBT=0:WEND
next a
goto HERE

ENDIF

First I would read all button input at once. Debounce and then decide what to do.

This is like a state machine coding and you will not loose any keypress, especially if it is interrupt driven. Or if you do not want interrupts, then a tight loop can do the job just fine.

Spaghetti coding unfortunately leads to such results.

Ioannis

Thanks everyone. I've modified that code in the way that it now works - there is additional check for MENUITEM value inside a button press loop, but the question is still active - why the code above slows down in that way? That's simply not logical.

if there is room, you could put some 'temporary' code to serout or debug at a few locations and see where it isn't doing what is expected ! looks like there are quite a number of 'states' your program could be looping through.