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XU4 Boot Loop With Touch Panel Plugged In

Posted: Fri Jun 14, 2019 6:00 pm
by Clayton2017
I’m working on a project, a car multimedia/headunit thing. I Originally was going to use a Rock64 after a weeks of trying to get that to work, and $100 later in having to buy many wifi dongles and Bluetooth moudules to try to find somthing to work I gave up. So few months ago I bought an XU4, fortunately atleast modules work from my now collection. It can’t run a wifi and a Bluetooth module together off its own supply, fine I can live with that. (Yes I have a more then overkill power supply for it. But that I can work around, what I really don’t want to work around is it bootlooping with a simple touch panel plugged in, this is even with the panel 100% running off a separate supply. Has no issues after boot with it but I would like to not have to get in, remember to unplug the panel, wait for it to boot, then plug it back in...

Oh what did I get myself into, I’ll never seem to learn from Chinese junk will I. The Rock64 was going to get the 20 lb rock taken to it but seems it’s the better option for that is the XU4 because the rock will Atleast boot with everything plugged in, no extra supplies nothing🤣 I’ll take Bluetooth not working witch makes my project harder but has a workaround, unlike not being able to boot with a simple touch panel connected.

From my test months ago if I remember correctly watching the current drawn, with the panel plugged in it doesn’t even reach the ~1.5 amp draw during boot (that would be the real boot cycle), it just crashes in the ~500 mA loading sequence

XU4 with active cooler, 16GB EMMC, loaded with whatever the android is. RTC battery, hardkernal usb cable,

P.s. I will not respond to stupid questions, yes I tried all ports, yes my supplies are more then sufficient, yes i turned it on and off, yes common grounds for the touch panel on a Separate supply. Yes the cable is the hardkernal official, and EMMc, also, at this point I’ve spend so much money on playing the game “see if it works on the Chinese garbage can” I’m most certainly not buying another screen, that’s already all in its housing... this either works or it (XU4) is going to be a concrete slab, and big rock sandwich. :lol:

Pps: if it wouldn’t also boot loop with only a wifi module plugged in using the power from the board that would be nice too...

Re: XU4 Boot Loop With Touch Panel Plugged In

Posted: Sat Jun 15, 2019 1:16 am
by Tomas J.
Did you made +5V measurements on extension header pins? Possible to much resistance on XU4 barrel connector?

Re: XU4 Boot Loop With Touch Panel Plugged In

Posted: Sat Jun 15, 2019 11:13 am
by Clayton2017
Wow! I would never of thought to check that! I must be some retard! But anyway moving on from that, only talking about the touch panel, that boot loops the system 100% completely separate supply, and no way to pull power from the XU4. With only D+ D- and gnd connected. Oh but yes that’s obviously the XU4 not getting enough power, even though it boots fine without the accessory that pulls no power from the board. But plugging in this no power drawing accessory is too much for it to handel apparently.

Re: XU4 Boot Loop With Touch Panel Plugged In

Posted: Mon Jun 17, 2019 1:27 pm
by odroid
Do you use our official 5V/4A PSU?
Can you find a rated power consumption of the touch-panel?

Re: XU4 Boot Loop With Touch Panel Plugged In

Posted: Mon Jun 17, 2019 8:02 pm
by Clayton2017
No, but a really good bench power supply with power requirements more then capable of handling this. And since I have to answer the obvious questions witch I’m well aware you have to deal with but I dedicated a big portion to my initial post asking you not to do that because it’s insulting, you’re not dealing with a 12 year old. And a waste of both ours time. It’s been reflashed, the power cable is the official, my power supply is more then suitable I’m not buying yours, I’ve checked voltage and voltage drop. Yes it’s actually plugged in. I KNOW it’s not a power issue.

Here’s why: it boots fine on its own and with more devices then this just one off its internal power distribution. But as I’ve stated couple times now, the touch panel is running off an entirely separate channel on my power supply, pulling 100% of its load independently of the XU’s but it still does it. 5v completely disconnected on the USB between. Only D+ D- and Gnd. I know the “power” used for data transfer is not setting the XU over (witch would be really sad) because I can load up the USB ports with other accessories that work and it’s perfectly fine. USB is USB, its a standard protocol. And so is it’s communication

[X] Everything stupid and obvious
[X] Issue is not a power issue because it literally is incapable of pulling power from the XU as it does not draw power from the same “supply” and is isolated unless
[ ] Magic may exist to where phantomly, over the air and magically it can draw power (untested, I’m sure it’s this one, come back later)
[X] “Power” issues that may pertain to the USB protocol are ruled out
[ ] Answer the next question asking me to check how much power the magical panel can pull from the electrically isolated board.

Re: XU4 Boot Loop With Touch Panel Plugged In

Posted: Tue Jun 18, 2019 9:27 am
by odroid
Well understood.
But it is very worth to measure the voltage of 5V0 rail on the 30pin header with a DMM when the system boots. ... _2x15_pins
It must be stable at 4.8V~5.2V.

BTW, do you know the VID/PID of your touch screen controller?
We've supported various touchscreen via this long thread.

Re: XU4 Boot Loop With Touch Panel Plugged In

Posted: Sun Jun 23, 2019 4:11 am
by phaseshifter
look`s like a power problem of some description to me.....!!!

you may be back feeding the xu4 with power somehow...this may cause an issue...or some other device you have connected to and or via the xu4....
did you also run a full update on the xu4...

also it could be poor quality media...pls don't use kingston...

Re: XU4 Boot Loop With Touch Panel Plugged In

Posted: Tue Jun 25, 2019 3:13 am
by Clayton2017
As stable as it gets, exact same as having nothing plugged into it. It’s it’s very much “supported” because I can plug it in after it starts and works like a dream.

I know, that’s why I isolated it and keep repeating myself because I know everyone is going to cry “POWER SUPPLY YOU STUPID, POWER SUPPLY” unless it’s back feeding through ground or the data pins I’m pretty sure thats highly unlikely, And even so, it wouldn’t work after booting, magic smoke would escape ☺️ Also the odroid EMMC module thanks 😊

Anyone got help other then pointing fingers? Again, not some 12 year old kid, full grown adult, with an electrical degree, and make things all the time. All the basic troubleshooting is done, official cable, board, and memory module, the only thing that’s not is a beefy bench power supply that’s more then sufficient, and the only potential problem is HardKernal potentially locking out non official power supplies somehow, which sounds like them but not plausible because I can get it to boot with other things that actually draw power fine, but the one mystical thing that doesn’t draw power is too much for it to handle... it’s been flashed, reset, and even used a different EMMc module.

Re: XU4 Boot Loop With Touch Panel Plugged In

Posted: Tue Jun 25, 2019 9:34 am
by odroid
Okay. Let's move to the next step since you believe the power source, cables and DC-plug are reliable.

Do you have a 1.8Volt USB-UART cable to monitor the system status to find a root cause of the boot-loop?
Something like this?