Button example - Help

Squirrel Code
1

I have been tring to understand the Button behaviour and wonder if i am right:

This is my class:

// Buttton Class
class Button extends IoExpander
{
// IO Pin assignments
pinButton = 0;
state = 0;

constructor(port, address, pinButton)
{
    server.log(format("constructor"));
    base.constructor(port, address);
    
    // enable pin as active
    setPin(pinButton, 0);
    
    // set button IRQ
    setPullUp(pinButton, 1);
    setIrqMask(pinButton, 1);
    setIrqEdges(pinButton, 1, 1);  // Set for rising and falling        
}

// Read button
function readState()
{
    state = getPin(pinButton);

    //server.log(format("debug %d", state));
    return state;
}

}

Then i initialize and read the button every sec.
If i press the button for more than a sec, i get chaotic behaviour. Like several 1 and 0s from the read.

How should i get process the button read output?

thanks
Patrick

2

If you’re polling the button, then you shouldn’t be enabling the interrupt on it (the “set button IRQ” bit).

You may be seeing switch bounce if you see some instability around either a press or a release; you need to wait until it settles, generally. Can you post all your code?

3

Thanks Hugo for the quick reply!

I am using the IoExpander class as a base for my Buttton class.

Then I initialise and use Button like this:

`
local button1 = Button(I2C_89, 0x3E, 1);
local button2 = Button(I2C_89, 0x3E, 2);
local state1 = 0;
local state2 = 0;

// Test
function change()
{
// Schedule the next change
imp.wakeup(0.5, change);

// Read the button
state1 = button1.readState();
state2 = button2.readState();

if (state1==1 || state2==1){
    server.log(format("state - button 1 is %d - button 2 is %d", state1, state2));
}

}

// Register with the server
imp.configure(“Test Button”, [], []);

change();
`

I have commented the IRQ code, and kept the line for the PullUp like this:
setPullUp(pinButton, 1);

This is what i get, if i output all read, and press on one button:

Sunday, September 16, 2012 11:07:12: state - button 1 is 0 - button 2 is 0 Sunday, September 16, 2012 11:07:13: state - button 1 is 0 - button 2 is 0 Sunday, September 16, 2012 11:07:13: state - button 1 is 1 - button 2 is 1 Sunday, September 16, 2012 11:07:13: state - button 1 is 1 - button 2 is 1 Sunday, September 16, 2012 11:07:14: state - button 1 is 0 - button 2 is 0

I know i need to De-bounce the button, but why do I read 1s on both buttons, if i press one?

Is my initialisation is good (GPIO) for the button?
setPin(pinButton, 0); setPullUp(pinButton, 1); // not sure is it for

You have an example of code for polling the button state?

4

I think I need to see the button class to work this out. Could you put it on pastebin.com and attach a link?

5

Hugo,

I have placed the complete code on http://pastebin.com/ETHH1WN9
I am looking forward to understand my mistake.

Should I use IRQ instead of polling for a button?

Thanks for your time
Patrick

6

Ok, so I found two issues:

  1. The buttons are on GPIO 0 and 1, not 1 and 2
  2. You were shadowing the pinButton value in your constructor, hence it was only ever looking at GPIO 0.

My modified constructor looks like this:

` constructor(port, address, pb)
{
server.log(format(“constructor”));
base.constructor(port, address);

    // Save pin
    pinButton = pb;
    
    // enable pin as input with pull-up
    setDir(pinButton, 0);
    setPullUp(pinButton, 1);
    
    // set button IRQ
    //setIrqMask(pinButton, 1);
    //setIrqEdges(pinButton, 1, 1);  // Set for rising and falling        
}

`

…even if the constructor parameter name is the same as a class variable, it won’t magically assign - the parameters to the constructor are local to that function, not the class.

Now it seems to work for me. Here’s my complete code: http://pastebin.com/kX3EHe4z

7

Thanks Hugo, basic cut and paste. I should have catch this.

It seam i was missing the setDir to set the input too.

Regards,
Patrick