Disable or move console to fake terminal when USB is disconnected

[espruino-discuss3]

Posted at 2014-06-09 by aerialist_user6911

Hi!

How could I stop Espruino to move console or force it to move to Serial6 (which does not exist on Espruino board?) when USB cable is disconnected?

I saw the case to do it after boot by defining onInit function and call setConsole() there.
http://forum.espruino.com/conversations/863/#comment11883

Is there event to watch for USB cable disconnected so that I can call Serial6.setConsole()?

I embed Espruino into a keyboard together with Adafruit EZ-Key module. Espruino scan the keyboard and send data which key is pressed to EZ-Key via Serial1(B6, B7). EZ-Key act as a BT Keyboard for iPhone. All USART1-5 enabled ports are used for keyscan excpet B6 and B7. I do want to have console on USB for debug but I also like to use it without USB connected for real use.

[espruino-discuss3]

Posted at 2014-06-09 by @gfwilliams

You should be able to do LoopbackA.setConsole () on onInit - LoopbackA goes to LoopbackB and vice versa. If you've explicitly set the console then it shouldn't move when USB is plugged in, so I guess you could make a handler for USB.onData that would swap the console back to USB when you pressed a button.

That way you could get USB comms when you plug in, and after power cycling/saving it would go back to being on Loopback...

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Posted at 2014-06-10 by aerialist_user6911

Thank you very much for you advice, Gordon!

Doing LoopbackA.setConsole() on onInit works great! Serial1 is quiet now ;-)

you could make a handler for USB.onData that would swap the console
back to USB when you pressed a button.

I couldn't fully understand your suggestion.
Do you mean

USB.onData(function (e) { USB.setConsole(); });

?
It seems overkill to on every character received on USB.
Or perhaps you meant assigning USB.setConsole for a press of button?

function onInit(){
  LoopbackA.setConsole();
  setWatch(function(){ USB.setConsole();}, BTN, true);
}

Anyway, above onInit function seem to behave as I wanted.
(just have to remember to call onInit or LoopbackA.setConsole(); on WebIDE before unplugging USB.)

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Posted at 2014-06-11 by @gfwilliams

Glad it's sorted!

You could maybe do something like:

USB.onData(function (e) { 
  USB.setConsole(); 
  USB.onData(undefined);
});

So that only the first character received will call the callback... But if you're not using the button for anything, it's a nice easy way of working. I guess you could make it toggle back and forth? You can check what the current console device is using process.env.CONSOLE

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Posted at 2014-06-12 by aerialist_user6911

Thanks again, Gordon!

setWatch(function(){ 
			if (process.env.CONSOLE != "USB"){
				USB.setConsole();
			}
			else{
				LoopbackA.setConsole();
			}
		}, BTN, {repeat:true, edge:"rising", debounce:10 });

Taking your advice, I made it to toggle.
But your USB.onData(undefined); solution is a lot nicer !

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Posted at 2015-11-12 by Sacha

Hi Gordon

USB.on('data',function (e) { 
        USB.setConsole(); 
        USB.on('data',undefined);
});

Is working as expected, but a warning is signaled:

WARNING: Second argument to EventEmitter.on(..) must be a function or a String (containing code)

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Posted at 2015-11-13 by @allObjects

...what about passing an 'empty' function instead of undefined?

USB.on('data',function () {
    USB.on('data',function(){});
    USB.setConsole(); 
});

...with setting the on-handler first and then the redirect...

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Posted at 2015-11-13 by @gfwilliams

XXX.on('yyy', ...) will add an event listener to the list of event listeners, rather than replacing the existing one like I think you intend...

If you want to remove an event listener, just use USB.removeAllListeners('data')

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Posted at 2015-11-13 by @gfwilliams

Also... When the console is on USB (or any device for that matter), existing listeners for the data handler won't get called, so there may not be any point removing them.