OTA and analogRead

[szerwi]

Hi,

When I have OTA enabled in my code, the analog reads are always 4095. I use pins 14, 4 and 2 and all of them aren't working.

[me-no-dev]

I do not see why OTA would mess with anything. It's only network and flash access.

[szerwi]

I don't understand it to, but it's not working.

[Raienryu97]

Hey @szerwi since you said you have OTA code I'm assuming you obviously have WiFi on.
With reference to igrr's comment
Pins 2,4 and 14 all belong to ADC2, they will al give the highest value 4095 (been there, suffered that :) )
You need to use ADC1 channel when you have WiFi on.
Check the pinout and use one among ADC0-ADC7
It helped me out.

[me-no-dev]

yup... I was confused at thinking it was the other ADC that would go off

[szerwi]

So all ADC10+ pins belong to ADC2? Thare are only 6 pins that belong to ADC1?

And is there any way to use ADC2 pins while OTA enabled? I need at least 7 analog pins for my project :/

[Raienryu97]

I think it is a design limitation that ADC2 will not work, I do not know the specifics of why, but ADC0-ADC7 is 8 Analog pins, is that not enough?
If not, then I guess buying external ADCs and connecting to non ADC1 GPIO could help you out.

[szerwi]

@Raienryu97 but there's no ADC1_1 and ADC1_2, or am I blind?

https://www.google.pl/search?q=ESP32+pins&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiqgMqHluXUAhUBVRQKHX2QCZgQ_AUICigB&biw=1920&bih=950#imgrc=rfUUzNMMCSZiEM:

[Raienryu97]

Use one among ADC0 - ADC7 here.

[szerwi]

I realised that two sensors can be connected to digital pins, so I think 5 analog pins are enough. Will pins that are ADC2 work as digital pins properly when WiFi enabled?

[Raienryu97]

As digital pins, they should work.

[szerwi]

Ok. Thanks for help. It's stupid that while WiFi enabled, this analogs don't work... :D

[szerwi]

I've connected sensor to ADC1 pin and I'm calculating something. With OTA disabled the result is -0.9, but with OTA enabled the result is -1.2. Any ideas? :D

[szerwi]

Sometimes when the ESP is turning on, and when OTA is enabling I have an error:

Guru Meditation Error of type IllegalInstruction occurred on core 0. Exception was unhandled.
Register dump:
PC : 0x400fbf44 PS : 0x00060b30 A0 : 0x8010318f A1 : 0x3ffd0ab0
A2 : 0x00000000 A3 : 0x3ffd6d94 A4 : 0x3ffd0b10 A5 : 0x0000000d
A6 : 0x0000001f A7 : 0x3ffd6a74 A8 : 0xf0029056 A9 : 0x3000012f
A10 : 0x0000000d A11 : 0x00000001 A12 : 0x00000002 A13 : 0x00000025
A14 : 0x00000006 A15 : 0x00000005 SAR : 0x00000013 EXCCAUSE: 0x00000000
EXCVADDR: 0x00000000 LBEG : 0x4000c46c LEND : 0x4000c477 LCOUNT : 0x00000000

Backtrace: 0x400fbf44:0x3ffd0ab0 0x4010318f:0x3ffd0b00 0x4010395c:0x3ffd0bd0 0x40093a04:0x3ffd0bf0 0x400952de:0x3ffd0c40

CPU halted.

But it's only from time to time, not always...

[Raienryu97]

Use the esp exception decoder and paste your backtrace there, that should give you an idea :)