Dear Mr. jgustavoam,

I do not get your results - and they are impossible.
Your display of channel 2 is wrong - I tested it with my scope.

With the PWM-frequency at pin 2 and connected to the interrupt pin 4 the following will happen:

Interrupt routine 5 is called. The total time from external ...

My measurements show: 1.7 µs from external interrupt to interrupt routine => about 500000 Interrupts/s.
If you are willing to dedicate core 1 only for "interrupts" you can work with more than 3.000.000 interrupts per second.
Look at
https://github.com/MacLeod-D/ESp32-Fast-external-IRQs

My measurements:
From external interrupt to interrupt routine; 1.7 µs
From external interrupt to RTOS task via interrupt routine like you do: 7.6 µs

So there should be no problem.

May you want to look at:
https://github.com/MacLeod-D/ESp32-Fast-external-IRQs

The ESP32 has 2 cores and for most applications one core running RTOS-tasks is enough.
If we dedicate the 2. core to a single - never interrupted - task we can achieve - while running a WebServer !

- count and react on more than 3,000,000 external "interrupts" per second
- building pulses with a ...

@edigi32
You are right!
As I mentioned: "this workaround may help."
It is an act of despair. But the prices of ESP32 are so low
Maybe for some of us it is a solution.

Maybe you may want to test:

esp32.com/viewtopic.php?f=19&t=2881&start=30

Posted: Sat Aug 10, 2019 12:30 pm

You may calibrate your own ESP32( the nonlinear 11DB curve) with this program.<br>
All you need is a wire from pin 25 to pin 35 and a normal voltmeter.<br>

Calibration is done automatically ...

Maybe you may want to test:

esp32.com/viewtopic.php?f=19&t=2881&start=30

Posted: Sat Aug 10, 2019 12:30 pm

You may calibrate your own ESP32( the nonlinear 11DB curve) with this program.<br>
All you need is a wire from pin 25 to pin 35 and a normal voltmeter.<br>

Calibration is done automatically ...

Maybe you may want to test:

esp32.com/viewtopic.php?f=19&t=2881&start=30

Posted: Sat Aug 10, 2019 12:30 pm

You may calibrate your own ESP32( the nonlinear 11DB curve) with this program.<br>
All you need is a wire from pin 25 to pin 35 and a normal voltmeter.<br>

Calibration is done automatically ...

Is it possible to get precise results from ESP32-ADC ?
As told we need a LUT for that.

I could not resist to do it myself as a proof of concept :D

AND FOR ME IT WORKS VERY WELL.


This time I estimate the ESP32-DAC produces correct values.

====================== NOTE ...

Original_Output.jpg
( for the images 10 bit values are used: DA>>2, AD<<2)


I got same strange results like vseven in his first post.
I wanted to put DA voltage (8bit) to pin 25 (DAC_CHANNEL_1) and then (pin 25 connected to pin 35) read back the voltage with adcStart(35),adcEnd(35); shifted from ...