Expose on-board button

[norgeous]

Hello, I do not own any loose electronic components to do proper GPIO with. I see that it's possible to access the onboard status led with: https://github.com/sandeepmistry/node-chip-io/blob/master/examples/blink-status.js

But is it also possible to access the tiny onboard button as seen in the very bottom left (beside LCD-HSYCN)?

It would be great to be able to do the same as: https://github.com/sandeepmistry/node-chip-io/blob/master/examples/led-button.js but with the onboard button and status led.

[sandeepmistry]

Hi @norgeous,

Good question. I believe that button is to manage the AXP290, so if you hold it the chip will power off, then you can turn the CHIP back on by pressing it again..

I would suggest you get a button or simulate a button with a wire connected to 3.3V or GND for testing.

[norgeous]

Thanks! Yes, holding the button does force a shutdown but the button is not exclusively for this. It can also be used for short presses and accessed in bash using these commands

/usr/sbin/i2cget -f -y 0 0x34 0x4a           # get button value, 0x01=off and 0x03=on
/usr/sbin/i2cset -f -y 0 0x34 0x4a 0x2       # resets button value to 0x01

Here is a one line test program for your SSH:

while true; do /usr/sbin/i2cget -f -y 0 0x34 0x4a; /usr/sbin/i2cset -f -y 0 0x34 0x4a 0x2; sleep 2; done;

If the status led access code new chipio.StatusLed(); uses i2cset behind the scenes, can't this onboard button be accessed in the same way? I'm new to all this GPIO/i2c stuff...

I guess the real tricky part is making the button 'realtime', accessing it without the polling (every 2 seconds in my bash example above) would be awesome. Linked up to be event driven would be perfect!

Given the above info maybe reopen this bug?

[sandeepmistry]

Ah, interesting!

We can add a entry to the tick loop which happens every 19ms like for the internal temp and battery: https://github.com/sandeepmistry/node-chip-io/blob/master/lib/axp209.js#L41-L53

Do you think you can work on a PR for this?

[norgeous]

I think I could, and had literally just found that exact file moments ago... I would start by adding:

var BUTTON = 0x4a;

but idk where i'd go from there... I think it would be way faster if you could implement this (pretty please).

[norgeous]

Just a little reiteration on my first post to save you some time...

The button acts kind of like a toggle, once pressed /usr/sbin/i2cget -f -y 0 0x34 0x4a will always return 0x03.

Un-toggling is achieved with /usr/sbin/i2cset -f -y 0 0x34 0x4a 0x2 and now the i2cget command will now return 0x01

[sandeepmistry]

@norgeous please see #25 and try it out + provide your feedback :)

[norgeous]

Yes, certainly! I will check if it's working, shortly... Thanks!

[norgeous]

I just tested it on a fresh stock flash (4.4 headless) with git (2.1.4) , node (v6.8.1) and build-essential installed, with the following commands:

git clone https://github.com/sandeepmistry/node-chip-io.git -b button
cd node-chip-io
npm i
node examples/onboard-button.js

and it looks like it works perfectly! I get down then up instantly logged to the console on each press.

If I create a PR for a new file examples/status-onboard-button.js (fits current name structure) which would trigger the onboard led with the onboard button, would you merge it?

These new features make me to think that a few of the terms in the examples/ folder should be redone to clarify things... perhaps status should be onboard-led but will leave that for now... perhaps a separate PR.

Thank you for your time spent on this improvement to the project!

[norgeous]

actually, it's not working as I expected it to... pressing the button does give down then up to the console, but both are displayed on button release.

Button down gives nothing, but release gives both down then up immediately. Is this intended?

[norgeous]

also, FYI a little further testing reveals:

power:

1. holding the button for 6 full seconds turns off the chip.
2. Press for 1 full second to switch back on.

short press:

1. a 'short press' appears to be less than 2 seconds
2. holding the button for more than 2 sec, but less than 6 sec does nothing (0x34 0x4a remains unchanged) something described below.

times are approximate.

[norgeous]

I just discovered something else by running:

while true; do /usr/sbin/i2cget -f -y 0 0x34 0x4a; /usr/sbin/i2cset -f -y 0 0x34 0x4a 0x03; sleep 0.5; done;

With this script we are setting as 0x03 instead of 0x02, now both long and short presses can be read:

short = 0x02 long = 0x01

In both cases setting it as 0x03 returns 0x00 - which is way more intuitive.

Thing is, I don't think the short press bit is set until the button is released, so I don't think you will be able to fix the onboardButton.on('down'... as the button will not tell us once the button is pressed (only on release).

Conversely, for long press the bit is set to 0x01 immediately without releasing it and there is no bit change on release.

Would be nice to include these features also, or just remove the on down function.

Thanks @sandeepmistry!

[norgeous]

as it is a non-standard button and will not behave with down and up, perhaps you could code some custom events such as:

onboardButton.on('short', function() {
  console.log('short');
});
onboardButton.on('long', function() {
  console.log('long');
});

idk if this is possible.

[sandeepmistry]

@norgeous thanks for trying it out and the feedback!

If I create a PR for a new file examples/status-onboard-button.js (fits current name structure) which would trigger the onboard led with the onboard button, would you merge it?

Yes, that would be cool.

Is this intended?

Not intended but it's a limitation of AXP290, it doesn't given you the press event just the release as you mentioned.

What if we just remove the press event from the example?

[sandeepmistry]

@norgeous ping ...

[norgeous]

What if we just remove the press event from the example?

Yes, I think that's a good compromise.

I will prepare a PR for the other example, shortly (I hope).

[sandeepmistry]

Closed via #25.