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Start up delay with Feather M0 Bluefruit LE
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Start up delay with Feather M0 Bluefruit LE

by Mitim on Fri Nov 08, 2019 8:58 pm

Hi,

I'm using a Adafruit Feather M0 Bluefruit LE with the arduino ide and I just discovered something that I'm not sure if it is possible to resolve (or at the very least, not sure how to go about it).

I noticed that during power up, there is a small delay before my program actually starts execution.

It's quite easy to reproduce, the code to do so is very bare bones; it just turns on an led:

Code: Select all | TOGGLE FULL SIZE
void setup(){
   pinMode(6, OUTPUT);
   digitalWrite(6, HIGH);
}

void loop(){} // no logic here
What happens is this:
1.) Power is applied
2.) The red led by the bluetooth module blinks on and off three times (this seems to takes up ~500ms)
3.) My program starts and my led turns on.

Is there any way to skip the delay or reduce it in step 2? I'm assuming it is waiting on the bluetooth module to wake up and is doing a blocking wait call? I don't need bluetooth right away, so is it possible that could be controlled and invoked by me later or if that blocking call could be changed to have non blocking logic?

The reason why I need a very short delay between power on and something being able to happen is my power trigger is touch based and it's not a great experience when someone touches it and nothing happens unless they keep touching it for at least half a second.

I have looked at sleep as a way instead of cutting power entirely to the controller, though I haven't cleanly been able to get that working (nor do I know if it has an 'instant' wake up time yet). I can seemingly put the controller to sleep but can't seem to wake it up via interrupt. But perhaps that's a different topic that warrants a different post.

At the moment if it would be a lot easier/cleaner for me if I could remove that delay. Any ideas?

Tim

Mitim
 
Posts: 11
Joined: Fri Jan 20, 2017 1:45 am

Re: Start up delay with Feather M0 Bluefruit LE

by Mitim on Sat Nov 09, 2019 5:35 am

Since I can't edit...
Mitim wrote:2.) The red led by the bluetooth module blinks on and off three times (this seems to takes up ~500ms)

I went back and timed it and it is more like 2 full seconds.

Mitim
 
Posts: 11
Joined: Fri Jan 20, 2017 1:45 am

Re: Start up delay with Feather M0 Bluefruit LE

by Ashfox on Fri May 14, 2021 7:21 pm

@Mitim

I see this post was a while ago, I'm having the same issue, did you find a solution? Many thanks....

Ashfox
 
Posts: 10
Joined: Fri Jun 19, 2020 5:27 am

Please be positive and constructive with your questions and comments.