what does "setNew interpreter error: LOW_MEMORY,MEMORY" mean?

[espruino-discuss3]

Posted at 2018-06-02 by BootySnorkeler

Title says all.
I keep getting errors that say "setNew interpreter error: LOW_MEMORY,MEMORY."
I'm assuming it means my Espruino Pico is out of RAM but then again, my code is only 13 lines.

function pause(){}

while (1) {
  digitalWrite(A4, 0);
  setTimeout('pause()', 20);
  digitalWrite(B4, 1);
  digitalWrite(B3, 0);
  setTimeout('pause()', 20);
  digitalWrite(A4, 1);
  digitalWrite(B4, 0);
  setTimeout('pause()', 20);
  digitalWrite(B3, 1);
}

Please help!

[espruino-discuss3]

Posted at 2018-06-02 by Wilberforce

I think you are expecting your setTimeout('pause()', 20); to delay the running of the code for 20 milliseconds.....

What you have written is basically this:

while (1) {
  digitalWrite(A4, 0);

  digitalWrite(B4, 1);
  digitalWrite(B3, 0);
 
  digitalWrite(A4, 1);
  digitalWrite(B4, 0);
 
  digitalWrite(B3, 1);
}

So it is looping forever toggling the state of the pins. It is also adding new timeouts, faster than they can be executed.

The timeout calls are a callback. This means that pause() will be called 20 milliseconds later, however the next statement digitalWrite(B4, 1); gets written straight away - it does not wait 20ms before doing that.

To achieve what you want - you will need to chain calls so that the next action occurs in a call back - not directly.

I hope this helps.

---

Posted at 2018-06-04 by @gfwilliams

As @wilberforce says...

Just to clarify though LOW_MEMORY,MEMORY means:

• LOW_MEMORY - Espruino ran low on memory while executing code, and had to delete command history and some other stuff so it could try and run your code properly
• MEMORY - Espruino totally ran out of memory and couldn't execute and more, so it had to stop running your code.

The code you actually want (using timeouts as intended) is probably:

function go() {
  digitalWrite(A4, 0);
  setTimeout(function() {
    digitalWrite(B4, 1);
    digitalWrite(B3, 0);
    setTimeout(function() {
      digitalWrite(A4, 1);
      digitalWrite(B4, 0);
      setTimeout(function() {
        digitalWrite(B3, 1);
        go();
      }, 20);
    }, 20);
  }, 20);
}

go();

Note that when you do it that way, you're actually able to do execute other code in the background as well, because you're not completely stopping execution.