Tiny Core Linux

Tiny Core Base => Raspberry Pi => Topic started by: pintman on April 02, 2018, 11:30:47 AM

Title: Meaning of LED blinking
Post by: pintman on April 02, 2018, 11:30:47 AM

Hi!

I installed picore on a RaspberryPi 3 and wonder what the blinking of the LEDs means. The red Power LED seems to be on when there is nothing going on and turns of if the CPU has some workload. The green activity LED on the other hand blinks now and then - maybe it has something to do with the networking?!

Can anyone point me to some clarification about this blinking?

Thanks für help. :)

Title: Re: Meaning of LED blinking
Post by: Rich on April 02, 2018, 12:17:05 PM

Hi pintman

Quote

In the later models (A+, B+, Pi 2 & Pi 3) the power LED is slightly more intelligent. it is connected to the 5V and will flash if
the voltage drops below 4.63V.

From:
https://www.raspberrypi-spy.co.uk/2013/02/raspberry-pi-status-leds-explained/

Title: Re: Meaning of LED blinking
Post by: pintman on April 02, 2018, 02:44:09 PM

Thank you for the link. Therefore, I assume that no modifications have been made for the picore distribution to change the default behavior?

Title: Re: Meaning of LED blinking
Post by: Rich on April 02, 2018, 02:49:50 PM

Hi pintman
The blinking suggests to me that your power supply voltage is dropping too low when you make the Pi do some work. Could
be a weak power supply or maybe excessive wire length between the Pi and power supply.

Title: Re: Meaning of LED blinking
Post by: Misalf on April 02, 2018, 05:23:14 PM

The green LED mostly indicates reads/writes to the µSD card.
It's used to indicate other things as well. Like blinking 10 times when the RPi shuts down or different "blink-codes" to indicate things like boot errors. Like "beep-codes" on traditional PCs.
I believe the OS doesn't have much control over the status LEDs or it would be pointless anyway, because the LEDs are controlled by the hardware/firmware to indicate hardware stuff.

Title: Re: Meaning of LED blinking
Post by: bmarkus on April 02, 2018, 10:31:38 PM

You can modify how LED(s) are working in config.txt or via /sys/class/leds For details read

https://monkeyinmysoup.gitbooks.io/raspberry-pi/content/5.2-leds.html

Title: Re: Meaning of LED blinking
Post by: pintman on April 03, 2018, 02:42:08 AM

Thanks for you answers. I powered the Pi with a Powerbank - maybe this could be the source of an error and lead to the blinking of the red LED.

I thought that picore boots into RAM completely. Therefor I was surprised to see the green LED blinking.

Title: Re: Meaning of LED blinking
Post by: bmarkus on April 03, 2018, 03:59:50 AM

Quote from: pintman on April 03, 2018, 02:42:08 AM

I thought that picore boots into RAM completely. Therefor I was surprised to see the green LED blinking.

piCore itself runs in RAM but by default extensions are loop mounted and not copied to RAM.

Title: Re: Meaning of LED blinking
Post by: pintman on April 03, 2018, 04:29:07 AM

Thanks for clarifying the loop-mount. Is it possible to boot extensions into the RAM, too?

When using a power plug instead of the powerbank the red LED now stays red. :)

Title: Re: Meaning of LED blinking
Post by: Juanito on April 03, 2018, 05:36:15 AM

yes, you can use the copy2fs flag