Push Button 'Menu' to Choose Variable.

[Tissy]

I would like to set up a simple 'menu' system at the beginning of some code to choose a Variable number.

At the moment i have a reset switch on MCLR, so i want to change that be the switch input (as the circuitry is already there) for the variable selection. I already have a switch on the INTRUPT which is used later on in the code.

So each time the button is pressed the variable counts from 1 to 10 and then back to 1 again. If there is no button push input for 5 seconds, the variable number is set (at whatever the last button push denotes) and then main code starts.

Has anybody performed a similar task and can provide an example piece of code?

Many thanks,

Steve

[Melanie]

Just think about what you need to do and program accordingly...

Rule 1. Increment a variable 1-10 if a Button is pressed.
Rule 2. This variable loops back to 1 if value 10 is exceeded.
Rule 3. Timeout and exit if Button has not been pressed for 5 Seconds.

	MyButton var PortB.0 	' Pin goes LOW when Button pressed

	MyNumber var Byte	' Variable 1-10
	MyTimeOut var Byte	' 5 second Timeout (100 loops of 50mS)

	MyNumber=1		' Power-On with this starting value
	MyTimeOut=0		' TimeOut starts from zero at Power-Up	

	While MyTimeOut<100
		If MyButton=0 then
			MyNumber=MyNumber+1
			If MyNumber>10 then MyNumber=1
			MyTimeOut=0
			Pause 50	
				' This Pause DEBOUNCES Button - do not remove it
			While MyButton=0:Wend
				' Wait here if Button held down
			else
			MyTimeOut=MyTimeOut+1
			Pause 50
				' This Pause is the Timeout Pause
			endif
		Wend

[Tissy]

Many thanks for your help Melanie, almost there.

I have tried to set up a visual represenattion of where the variable is at. To make things easier i have set it from 1 to 9. Depending on what number it is, depends what LEDs are lit.

I have used PWM on each LED so 1-3 is RED, lit dim for 1 and bright for 3. Then GREEN 4-6 and BLUE 7-9.

After the 5 second time out, i thought it would goto to the MAIN code, again this is signalled by a flashing LED sequence so i know it has times out on the 5 seconds.

A couple of problems at the moment, the code seems slow to show the coloured PWM LED. Also after the 5 second time out, it doesn't goto the main code.

I would like the coloured LED to stay lit at whatever stage until the next button push or unitl the time out occurs. Does the code below look right to you to achieve this? I'm sure i have done something wrong.

The idea is there, just not the practicle side of things for me yet!!

TRISB = %00000001

MyNumber    VAR Byte	' Variable 1-10
MyTimeOut   VAR Byte	' 5 second Timeout (100 loops of 50mS)

Red         VAR PORTB.1 ' All LEDs
Green       VAR PORTB.2 ' Connected between
Blue        VAR PORTB.3 ' RC pins and ground
Orange      VAR PORTB.4

MyButton    VAR PortB.0 	' Pin goes LOW when Button pressed

MyNumber=1		' Power-On with this starting value
MyTimeOut=0		' TimeOut starts from zero at Power-Up	


	While MyTimeOut<100
		If MyButton=0 then
			MyNumber=MyNumber+1
			If MyNumber>9 then MyNumber=1
			gosub MyNumberPWM
            MyTimeOut=0
			Pause 50	
				' This Pause DEBOUNCES Button - do not remove it
			While MyButton=0:Wend
				' Wait here if Button held down
			else
			MyTimeOut=MyTimeOut+1
			Pause 50
				' This Pause is the Timeout Pause
			endif
		Wend

main:
    high Orange
    pause 500
    low Orange
    pause 500
goto main

MynumberPWM:
    If Mynumber = 1 then PWM Red,1,255
    If Mynumber = 2 then PWM Red,25,255
    If Mynumber = 3 then PWM Red,255,255
    If Mynumber = 4 then PWM green,1,255
    If Mynumber = 5 then PWM green,25,255
    If Mynumber = 6 then PWM green,255,255
    If Mynumber = 7 then PWM BLUE,1,255
    If Mynumber = 8 then PWM BLUE,25,255
    If Mynumber = 9 then PWM BLUE,255,255
RETURN

Thanks again,

Steve

[Melanie]

I assumed the following that either... You will have a Pull-Up resistor on your Button pin (button pulls pin down to 0v), or you will have switched-on the internal weak pull-up's for PortB. If that button pin is floating, you will have unpredicatable results.

[Tissy]

Indeed you are right, the switch has a 47k pull-up resistor.

This is needed further on in the code as an interupt. How can i change this piece of code to reflect when it goes HIGH instead of LOW. I thought it may be just a case of changing:

While MyTimeOut<100
		If MyButton=1 then  ' Changed 0 to 1
			MyNumber=MyNumber+1

But it seems there is more to it than that? When MyButton=1, the LEDs just seem to cycle through there brightness levels.

Can you help??

Cheers,

Steve

[Melanie]

The code that I posted in its existing form is not suitable for interrupt use. It was posted to get you started. Consult the "ON INTERRUPT" statement in the PBP manual to see how you could modify for that purpose.

Changing the polarity of that statement would only be valid if the button pulled up to +Ve and the pin normally idled high.

[Tissy]

I believe it wasn't working properly due to the Interrupt settings which i have now disabled on PortB.0.

I have it working the way i want apart from one thing.

It recognises the push switch, displays the appropriate PWM and then if it reaches 9 goes to 1 again. Also, if no input for 5 seconds it starts the flashing sequence (just to signal the end of the 5 seconds).

How does one get the LEDs to stay in their PWM routine until the switch is pressed again, without using Interrupts. When the swicth is pushed it goes to the appropriate PWM routine but after the PWM cycle, the LED goes off.

Here is the code.

MyNumber    VAR Byte	' Variable 1-9
MyTimeOut   VAR Byte	' 5 second Timeout (100 loops of 50mS)

Red         VAR PORTB.1 ' All LEDs
Green       VAR PORTB.2 ' Connected between
Blue        VAR PORTB.3 ' RC pins and ground
Orange      VAR PORTB.4

DISABLE INTERRUPT
MyButton    VAR PORTB.0 	' Pin goes LOW when Button pressed

MyNumber=1		' Power-On with this starting value
MyTimeOut=0		' TimeOut starts from zero at Power-Up	

	While MyTimeOut<100
        If MyButton=0 then
			gosub mynumberpwm
            MyNumber=MyNumber+1
			If MyNumber>9 then MyNumber=1
            MyTimeOut=0
			Pause 50	
				' This Pause DEBOUNCES Button - do not remove it
			While MyButton=0:Wend
				' Wait here if Button held down
			else
			MyTimeOut=MyTimeOut+1
			Pause 50
				' This Pause is the Timeout Pause
			endif
		Wend

main:
    high Orange
    pause 500
    low Orange
    pause 500
goto main

MynumberPWM:
    If Mynumber = 1 then PWM Red,1,255
    If Mynumber = 2 then PWM Red,25,255
    If Mynumber = 3 then PWM Red,255,255
    If Mynumber = 4 then PWM green,1,255
    If Mynumber = 5 then PWM green,25,255
    If Mynumber = 6 then PWM green,255,255
    If Mynumber = 7 then PWM BLUE,1,255
    If Mynumber = 8 then PWM BLUE,25,255
    If Mynumber = 9 then PWM BLUE,255,255
Return

Many thanks,

Steve

[Melanie]

How does one get the LEDs to stay in their PWM routine until the switch is pressed again, without using Interrupts? When the swicth is pushed it goes to the appropriate PWM routine but after the PWM cycle, the LED goes off"

Unless you are able to write a program with an "active real-time" loop that executes continuous PWM (I do recall posting an example of such code dimming multiple LED's continuously sometime ago), the only option you have is chosing a PIC with multiple hardware PWM.