USB stays ON after power down

[jess]

I observe another strange phenomena when using LiPo 3.7V battery.
Here's a step-by-step observation:
- with battery disconnected run it from ACDC 12V/2A power supply; all works as expected
- power down the system and unplug 12V connector; measure +5V pin on usb hub - should be zero
- connect 3.7V LiPo and measure +5V pin on USB 3-port hub; still no voltage present
- press power-up button and start Olinuxino; works as expected with +5V available across all 3 usb sockets
- power-down the system but this time when measured the USB ports will keep showing around 3V on +5V usb ports despite the system OFF and powered down.

You can confirm that voltage "leak" by unplugging the battery and then plugging it again. The voltage's gone i.e. it's not just some capacitor left charged but true voltage "leak" through an unknown circuitry.

Why?

[JohnS]

Probably not fully off - see this thread as to how to get it off https://www.olimex.com/forum/index.php?topic=1225.0

See if that's it.

John

[granite_crusher]

this looks interesting (examine schematics and measuring voltage on troubleshoot pins on card):
DC (lets say 12V) gets converted to 5V (in schematics 5VEXT - troubleshoot pin P9); this should be 5V all the time, and AXP have no way to interact with it. Now if I understand intention of olimex there is jumper 5V_EN which is open, I guess it should make possible to have 5V on 5V rail even with system shutdown, but wait a minute, It is no need of that, because 5V is all the time on 5V rail (P6 troubleshoot pin) is system on or off. so that makes that jumper pointless, that makes me suspicious it is really something wrong in hardware. or AXP needs to be controlled by software all the time? (I tried measuring things without SD ) 3.3volt rail after power button hold for 6 sec would drop just to 2.2V, while with SD (with soft in) gets down to ~1 volt.
And without SD usb 5V is always on. so to put it off there is needs software part. output pins from axp (for example to processor) gets cut off (P1,P3,P4,P11) - these looks is hardware controlled.
Any ideas, solutions? Lack of power functionality makes it impossible to use this card for mobile projects.
I hope there would be good documentation of AXP in english. Its hard to believe there is no.