DevkitC v4 app start problem when externaly powered?

samsam
Posts: 34
Joined: Sun Jun 04, 2017 5:26 pm

DevkitC v4 app start problem when externaly powered?

Postby samsam » Tue May 08, 2018 3:20 pm

I just obtained and new DekitC v4 (with Wroom32 and Rev1 ESP32), but have problem starting the code when power it from external source - have to press the "EN" button in order the loaded app to start after powering on.
Only when I power the board from the USB port and the other end is connected to a computer, then this board/app starts normally.
Even if I power through the USB cable, but the other end is connected to a wall adapter - again have the same problem and have to press the "En" button to start the app.

With my older DevkitC board (but this one is not from Espressif, but from DOIT) I dont have such problem and the apps start without problem with all the available powering options.

I'm not sure this might have role in it, but the app that I'm testing on DekitC v4 is compiled with the new ESP-IDF ver 3.0, while the apps on old board are compiled with the old vesrion ESP-IDF (it still prints v3.0, but the development in progress version from more than a year ago)

Any idea what is the problem?
Last edited by samsam on Fri May 11, 2018 3:25 am, edited 2 times in total.

samsam
Posts: 34
Joined: Sun Jun 04, 2017 5:26 pm

Re: DevkitC v4 app start problem when externaly powered?

Postby samsam » Thu May 10, 2018 10:52 am

Sorry, I just realised I've provided wrong information in my initial post (already correct it) : The actual button that I need to press in order to start code running on DevkitC v4 when is externally powered is "EN"

TheSub6
Posts: 7
Joined: Thu Mar 15, 2018 1:24 pm

Re: DevkitC v4 app start problem when externaly powered?

Postby TheSub6 » Thu Oct 11, 2018 6:41 am

Did you find a solution? I have the same problem. Or kinda.

No Problem on a WROVER-KIT. The same code starts without problems. On the DecKitC I have to press the "EN" button. As far as I remember I hadn't had any problems when just using a simple blink example.

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krzychb
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Re: DevkitC v4 app start problem when externaly powered?

Postby krzychb » Fri Oct 12, 2018 3:41 am

Hi samsam and TheSub6,

Could you double check if this is not the issue described in Note on C15?

If you have C15 installed on your board then try removing it to see if this resolves the issue.

C15 has been removed ("NC" on the schematic) in the latest ESP32-DevKitC V4.

jackdew22
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Joined: Mon Mar 04, 2019 9:37 pm

Re: DevkitC v4 app start problem when externaly powered?

Postby jackdew22 » Mon Mar 04, 2019 9:42 pm

To anyone else having this problem with the DevkitC board try using another GND pin besides the one next to 5V pin. I wasted hours debugging this exact issue.. simply switching to the GND 5 pins down fixed everything!

samsam
Posts: 34
Joined: Sun Jun 04, 2017 5:26 pm

Re: DevkitC v4 app start problem when externaly powered?

Postby samsam » Wed May 29, 2019 12:45 am

Ok, finally found time to play back with this board:
Problem solved thanks to krzychb! Thanks!

So the problem was this capacitor C15 that is soldered parallel to BOOT button (I0).

Of course I tried first all the possible variants with the groundings without any particular result.
And by the way - this for the grounding I think is easy to find if you make couple simple measurements between all the 3 grounding pins what is the resistance and capacitance and if there is difference most probably will be enough to resolder that faulty pin.

And whoever will need to repair their boards too - pay attention that tracks beneath C15 are very easy to pill - I damaged one of the pads - not critical, but take in mind the component is very small and dont be lazy like me to use the first soldering iron you have on hand - the job need proper tool / tip if you want to preserve the tracks ;)

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