Power Up Problem << SOLVED >>

[RocketNut]

When I turn on the unit, the logic controller ( ItsyBitsy 32u4 - 3V ) does not boot up.
It boots up just fine when I connect the USB, then runs properly even when the USB is disconnected!!!
Yes, I checked the power. It is right on at 3.2V.
Here is a screenshot of the schematic.

Does anyone have any clue what is causing the problem?

[TomGeorge]

Hi, @RocketNut
Thanks for the image but a screen shot lacks definition.

The CAD program you are using should have an EXPORT facility, under the "Files" tab.

Thanks.. Tom...

[Wawa]

Parts of the diagram are cut off. I think I see a MAX1684, with a max operating voltage of 14volt, connected to 24volt. Please explain.
Leo..

[jim-p]

@RocketNut

does not boot up.

Do you mean not boot or that the program does not run.
If the later, then it could be the code. Do you use while(!Serial)?
Post your code.

[RocketNut]

What is MAX1684? I am not using that device.
jim-p yes I am using while(!Serial). Commenting them out solved the problem. Thanks for the clue
Is there a way to check if the USB is connected or not?

[TomGeorge]

Hi, @RocketNut

What solved it?

Tom..

[RocketNut]

Commenting out the while(!Serial) code fixed the problem. When it is boots up it hangs up because there is no USB connection. Which causes the while to enter a endless loop,

[PaulRB]

@RocketNut

Is there a way to check if the USB is connected or not?

Yes, that's effectively what 'while(!Serial)' does. But it takes a second or two to connect after plugging in, hence the while loop to wait for that to happen.

You can set a timeout:

void setup() {
  ...
  unsigned long startTime = millis();
  while (!Serial and millis() - startTime < 3000);
  ...
}