Entering Automatic Programming mode from USB-C

David_1
Posts: 6
Joined: Sat May 15, 2021 10:51 am

Entering Automatic Programming mode from USB-C

Postby David_1 » Sat May 15, 2021 11:24 am

Hi Everybody,
I seem to be struggling to find the right combination of values to make programming an ESP32 automatic.
My Goal is to run finished device on 12v DC in a vehicle so Must have a 12v input to power everything I decided I could only power CH340n from the host USB power. I think this was a bad move.
The normal Dev boards use micro USB plugs but I have tried to use USB-C. The schematic shows components without values. I am hopping someone can suggest working values for me to try. I have got scope traces of the rise and fall times of the CTS DTR lines each side of the transistors. I seem to have options of works from 5v and programs but wont run from 12v. Runs from 12v and 5v plugged in together but wont program. Runs from 12v with no programming but I can re-flash with OTA code from pc or phone.. Slow.
So the question, Is it possible to enter programming mode automatically and run finished device solely from 12v
https://1drv.ms/u/s!AtmN4LISfE0X-y2XgMv ... y?e=8zP3E4
Image

WiFive
Posts: 3237
Joined: Tue Dec 01, 2015 7:35 am

Re: Entering Automatic Programming mode from USB-C

Postby WiFive » Mon May 17, 2021 9:05 am

I have got scope traces of the rise and fall times of the CTS DTR lines each side of the transistors.
So is there a difference in the traces with different power supplies?

David_1
Posts: 6
Joined: Sat May 15, 2021 10:51 am

Re: Entering Automatic Programming mode from USB-C

Postby David_1 » Mon May 17, 2021 12:10 pm

I would of thought not, But confess I have not tried. But most of the time I run with unit plugged into pc for programming with a 12volt external power source when needed.
I have found if I use a 5volt backup battery

https://www.amazon.co.uk/Anker-PowerCor ... 3718220657

5volt back and external 12volt supply all is good, But my goal was to just power from 12Volt line. With the Diode between 5v_usb and 5v rails they way it is in the schematic planned to leave the CH340 unpowered when powered by just 12volts .. this failed turn diode around still fails to work from 12v only.
Pull RTS & DTR high with 10k also fails, Half planning to cut tracks between transistors and ESP32 next.

My easy all in one board is trying hard to make me loose my mind ! :)
So any suggestions to let this board run from 12v only would be gratefully received !

Thankyou
David

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