analogread won't work

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Re: analogread won't work

By tytower
- Fri Jun 12, 2015 10:51 pm #20309
Here you go, I even highlighted the trace for you ;)
Since these modules are meant to be mounted in other product, any external circuit on the TOUT pin would be kinda stupid, since according to the datasheet it would mess with the ESPs ability to measure it's supply voltage.
If you wish to discuss this further, please do so in a new thread.



You start a new thread if you wish . This is all to do with the correct reading of the ADC pin.
You have not highlighted the trace . You have drawn one in! Are you kidding mate?
If you have a circuit post it intact or just admit you are wrong!. You may be right but I need to see the circuit . Do you have one that I can read the pins even?

As far as an external circuit goes ,what is the pin for, if not to take an analog voltage reading from a sensor and convert it to a digital value. "ADC" "Analog to Digital Conversion" What's measuring its own voltage got to do with it?

There is a lot of consensus that this pin only reads to 1 volt or so . That may be correct but I have one (ESP12)running atm that is reading 2.85 Vols consistently. Thats why i am trying to establish exactly what the ADC pin is supposed to read.
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Re: analogread won't work

By cal
- Sat Jun 13, 2015 2:28 am #20319 Maybe both of you are right but for different configurations of the adc pin?
Putting different external hardware connections aside most of the pins are multipurpose.
The current behavior is defined by some control register.
You can probably enable pull up resistors on gpio pins and someone posted that resistors can be enabled
for adc pin to. That would explain reading 1V versus VCC to me.
If you don't need to monitor VCC you would configure and connect accordingly.
The sdk/firmware provides and documents different read functions for the adc documented in the espressif
docs. I would expect them to configure the adc differently before reading it out.
It's in one of the docs they provide on their forum. Don't ask me which.

Cal
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Re: analogread won't work

By M0ebius
- Sat Jun 13, 2015 8:20 am #20356 I have the same problem. It is even worse.

First i had the same improper readings (some values always in the range around 400 - could be compensated by code).
Then the esp run into a watchdog reset after some readings.
And in the end, it crashed immediately when calling analogRead().
All this happens even after reflashing the module.

But the same sketch works fine on another esp.

Finally (after many wasted hours of wondering and testing), i could resurrect the bad one by flashing the default firmware.

For me, this is a big issue, cause the firmware somehow modified itself to an unusable state. Or maybe there is a problem with the eeprom functions (but the error survives also flashing a new sketch).
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