On September 20, 2016 7:45:01 AM GMT+02:00, "H. Nikolaus Schaller"
hns@goldelico.com wrote:
- When the 5V LED is on (power is below 5.6V, which means it switches
to Power Jack Input), the EVM runs unstable. At least yours, mine and aTcs, from what we know. It seems Nikolaus' one is not affected (for whatever reason).
Well, I have never tested with higher voltages.
And you never tested the whole system, just the CPU itself (without using USB, HDMI, etc. with 5V) Which is a good information as well!
- What has the 5V switch to do with the power supply of the OMAP5?
Nothing.
That nothing seems to have a high impact regarding stability ;)
Except one thing: if there are power sinks at the USB ports which draw high current, switching might make glitches on the DC input. But I don't see how this should affect OMAP operation.
That theory has one problem: It doesn't crash while switching. If voltage you feed the EVM with is below 5.6V, it ALWAYS runs in that special 5V mode without any switching happening.
So it seems to have something to do with that mode, not with the switching.
What's interesting though: As it runs stable for you (without using HDMI or USB), it probably doesn't have anything to do with the AC adapter breaking down because of a too high power consumption. HDMI should not use as much power as running the OMAP5 with full power for a while!
Unless there is a bug which makes the OMAP5 have the same power consumption regardless you stress it or not, but that's what a good power supply which shows the Ampere can answer.
So why does simply using HDMI make the board run unstable, but only in that 5V mode?
- Is that a hardware bug of the EVM or a problem with the OMAP5?
I tend to think it is an EVM specific effect. Pyra does not have this switch circuit at all.
Does that mean the Pyra always run similar to the 5V mode or rather to the more than 5.6V mode (using SMPS)
It is mainly an automatic bypass of the 5.6V - 12V -> 5V converter (because USB and HDMI need 5V). It is bypassed if input voltage is low enough.
Hmm, could HDMI or USB cause a freeze of the OMAP5 if the voltage is not stable enough?
What Kernel are you using? I've upgraded to the letux 4.8 RC5 via aTc's repo update and noticed this behavior with my bench supply capable of delivering 4A.
5.1V - Some instabilities HDMI, SATA resets and USB devices blink
out.
Sometimes freezes before getting to X.
5.2V - Boots up Consistently. random Freezes when using Firefox when attempting to watch a Youtube video. Sometime just HDMI blinks out occasionally.
5.3V - Seems stable running CPU intensive things. Firefox running youtube video, running 720p video in smplayer and quake 2 at once. highest current draw observed ~1.6A during spikes. Random Freeze occurs generally within 5 to 10 minutes of use.
5.4V - Same as 5.3V
5.5V - Same as 5.4V
5.6V - 5V LED blinks, HDMI blinks out or won’t go into a resolution above 1024x768. Can seem to use firefox, youtube videos without issues.
5.7V - 5V LED is off, but turns on when drawing ~1A. HDMI working appropriately.
5.8V - Same as 5.7V
5.9V - 5V LED is off, but turns on when drawing ~1A. oddly the 1024x768 bug appears again at this voltage. powered off a few times to confirm it.
6.0V - 5V LED is only displays as on with current draw is ~1.4A.
Seems
stable otherwise.
6.2V - 5V LED is only blinked a few times, when the current draw briefly spiked about 1.6A. seems just as stable.
6.3V - 5V LED off completely. No noticeable blinks. appears stable.
On Mon, Sep 19, 2016 at 12:06 PM, Tony Lindgren tony@atomide.com wrote:
- H. Nikolaus Schaller hns@goldelico.com [160919 02:55]:
Am 19.09.2016 um 11:39 schrieb Grazvydas Ignotas notasas@gmail.com: I could give it a try on my uEVM to add another data point. FWIW my uEVM has been always rock stable (12V supply), but I haven't updated my kernel for a while.
Yes, would be nice to compare your results and observations.
My omap5-uevm is on a 5V power supply right now it seems, I'm pretty sure it used to have 12V supply earlier.
Regards,
Tony _______________________________________________ Kernel mailing list Kernel@pyra-handheld.com http://pyra-handheld.com/cgi-bin/mailman/listinfo/kernel
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