Power LED blinking meaning?

Hi, I’m trying to debug why my Nano randomly shuts down, and I’m trying to investigate if it’s power related. The nano is powered through the two 5V GPIO pins from a 5V voltage regulator with a 4% accuracy.

Several questions:

  1. I notice that the power LED blinks. Is this normal? I couldn’t find any documentation as to whether this has a semantic meaning
  2. I’ve measured the current going into the Nano, and I see only about ~0.3-0.5A even when the nano is in jetson_clocks mode at MAXN. When I stress test the CPU, I get about ~1A of current draw. Is this normal? I’ve also verified that POM_5V_IN from tegrastats shows appx the same readings in terms of wattage at 5V.

Is there anything else I should look into?

A simple way is to compare to the test result with DC jack power supply. If no random shut down with that, then it might mean the issue of power thru GPIO pins. And if it is power supply related issue, you should be able to capture voltage drop on 5V rail with oscilloscope.

Could you please answer the two questions that I had?

Power LED should be ON not blink, the power of stress depends on use case. The key point is random shutdown as you said, that’s obviously abnormal.

Okay, but the blink must have semantic meaning right? Someone explicitly coded that in, so what does it mean?

Hi,

Is the system still alive when you see the LED blink?

Yes

Are you able to check gpio (GPIO04 (GPIO3_PI.01).) status in debugfs?

Can you elaborate what you mean by that?

Hi,

GPIO3_PI01 is responsible for this LED and is gpio-65 in sysfs.

sudo -s
cat /sys/kernel/debug/gpio

And then check gpio65